CN1741246A - Fluorescent tubes and flat lights - Google Patents

Abstract

The fluorescent tube of the present invention comprises: a transparent tube having a closed cavity filled with gas; a pair of electrodes disposed at both ends of the transparent tube; a dielectric omnidirectional reflection layer disposed on the inner wall of the transparent tube to completely reflect ultraviolet light and confine it in the closed cavity; and a fluorescent layer disposed on the dielectric omnidirectional reflection layer to react with the ultraviolet light to generate visible light. The present invention further comprises a planar lamp structure containing the dielectric omnidirectional reflection layer.

Description

Fluorescent tubes and flat lights

technical field

The invention relates to a fluorescent lamp tube and a plane lamp, in particular to a fluorescent lamp tube and a plane lamp with a dielectric omnidirectional reflection layer.

Background technique

Because of its high luminous intensity and uniform luminescence, the lamp tube can be made into extremely thin and can be made into various shapes, and can also be made into a flat plate as a flat light source, so it is currently used in liquid crystal displays, scanners, and automotive instruments. It has been widely used in the fields of plate, micro-advertising light box and mirror frame production. Generally speaking, the cold cathode fluorescent lamp is usually used as the backlight of the above products, and it is a novel miniature strong light source.

A conventional cold cathode fluorescent lamp 100 is shown in Figure 1. There is a layer of fluorescent layer 105 on the inner wall of the transparent lamp 101. A pair of electrodes 103a and 103b are arranged at both ends of the transparent lamp 101. The transparent lamp is filled with mercury, Argon, neon, or xenon gas, when a high voltage is applied to the electrodes 103a and 103b at both ends, the gas in the transparent lamp tube 101, such as argon (Ar), will be ionized, and the excited electrons will collide with mercury atoms to generate ultraviolet light or Visible light, ultraviolet light 209 reacts with the fluorescent substance coated on the inner wall of the closed cavity to generate visible light 211 . However, the fluorescent layer 105 cannot completely absorb the ultraviolet light 209 to generate visible light, and part of the ultraviolet light 209 will be absorbed by the cavity wall and converted into heat or be consumed by penetrating the cavity wall, so that the traditional fluorescent tube 100 cannot effectively use the light generated by the excitation of the electric field. of ultraviolet light.

Contents of the invention

In view of this, the object of the present invention is to provide a fluorescent tube and a flat lamp with a dielectric omnidirectional reflector, wherein the dielectric omnidirectional reflector is formed on the fluorescent material and the inner wall of the tube cavity In between, the ultraviolet light that penetrates the fluorescent material is reflected back to the cavity, and the ultraviolet light is confined in the lamp cavity repeatedly and reflected in multiple directions, so that the ultraviolet light and the fluorescent material fully interact to release visible light to exhaust the ultraviolet light energy, improve the conversion efficiency of visible light, and the dielectric all-round reflective layer will not reflect visible light. The omni-directional reflective layer of the dielectric can increase the utilization rate of ultraviolet light of the fluorescent lamp, increase the brightness efficiency, and reduce the harm of ultraviolet light to the human body.

To achieve the above object, the present invention provides a fluorescent lamp, comprising: a transparent lamp having a closed cavity filled with gas; a pair of electrodes arranged at both ends of the transparent lamp; A layer placed on the inner wall of the transparent lamp tube to completely reflect the ultraviolet light and confine it in the closed cavity; and a fluorescent layer placed on the dielectric all-round reflective layer to react with the ultraviolet light to generate visible light.

To achieve the above object, the present invention provides a flat lamp, comprising: a first substrate; a second substrate, relative to the first substrate, wherein at least one of the first and second substrates is a transparent substrate; at least one gap a wall, placed between the first substrate and the second substrate, forming a gas-filled cavity with the first substrate and the second substrate; a dielectric omni-directional reflection layer, placed on the inner wall of the cavity, It is used to completely reflect the ultraviolet light and confine it in the cavity; and a fluorescent layer is placed on the dielectric all-round reflection layer, which can react with the ultraviolet light to generate visible light.

In order to make the above-mentioned and other purposes, features, and advantages of the invention more obvious and understandable, a preferred embodiment is specifically cited below, and in conjunction with the accompanying drawings, the detailed description is as follows:

Description of drawings

Figure 1 shows the structure of a traditional fluorescent tube

Fig. 2 is the fluorescent tube structure of the present invention with a dielectric omni-directional reflection layer

Fig. 3 is the planar lamp structure that the present invention has the omnidirectional reflection layer of dielectric material

Symbol Description

Fluorescent tube ~ 100; transparent tube ~ 101; electrode ~ 103a, 103b; fluorescent layer ~ 105; fluorescent tube ~ 200; transparent tube ~ 201; electrode ~ 203a, 203b; Layer ~ 207; Ultraviolet light ~ 209; Visible light ~ 211; Plane lamp ~ 300; First substrate ~ 301; Second substrate ~ 303; Cavity ~ 311

Detailed ways

FIG. 2 shows a fluorescent tube 200 with a dielectric omni-directional reflective layer in a preferred embodiment of the present invention, including a transparent tube 201, such as a glass tube, with a pair of electrodes 203a and 203b at both ends of the tube. In this figure, a cold cathode fluorescent lamp (CCFL) is taken as an example, and the electrodes are located inside the lamp. However, the electrodes can also be placed outside the lamp, eg in the design of an external electrode fluorescent lamp (EEFL). The inner wall of the fluorescent tube has a dielectric omni-directional reflective layer 205 and a fluorescent layer 207, wherein the dielectric omni-directional reflective layer 205 is placed between the transparent lamp tube 201 and the fluorescent layer 207, which is a light in the range of visible light. Periodically stack reflective layers for transparency. The principle of reflection is to use the energy gap phenomenon generated by the periodic structure to control whether light waves of a specific wavelength can pass through. The bandwidth and corresponding frequency of this energy gap can be controlled by different dielectric materials and period sizes. In fact, as long as the ratio of the periodic structure to the dielectric material is properly controlled, even a one-dimensional periodic structure can have a full range of energy gaps, that is, electromagnetic waves propagating from various directions to the structure within a specific frequency range. Modals will not be able to stretch. The approximate equation governing the energy gap is given below

$\frac{\mathrm{<span\; class="notranslate">\; \&Delta;\&omega;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; -</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\sqrt{{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; d</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\sqrt{{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$

Among them, n1, n2: reflection coefficient of different dielectric materials (dielectric material); d1, d2: thickness of different dielectric materials (dielectric material); c: speed of light; ω: angular frequency; a: period size (a =d1+d2), and the relationship between the two constants of A and B is as follows;

$\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\sqrt{{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\sqrt{{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\sqrt{{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\sqrt{{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$

For a specific d1/a ratio, the normalized energy gap size: (ω2-ω1/0.5(ω2+ω1)) can be controlled by the ratio of reflection coefficients of different materials. If the reflection coefficient of one layer of dielectric materials is fixed, for example, n1 is a fixed value, the larger the difference in reflection coefficients of the two layers of dielectric materials, the larger the normalized energy gap. At this time, the electromagnetic wave of a specific frequency in a wider range can not be transmitted to another medium, so as to achieve the effect of omnidirectional reflection.

The periodic stacked reflective layer that is transparent in the range of visible light is, for example, a stacked structure of at least two materials in SiO2, AlN, ZnO, Al2O3, Ta2O3 or TiO2, preferably a periodic stacked structure formed by SiO2/Al2O3, such a composition Dielectric periodic dielectric mirror, its loss is very low, like a perfect mirror (perfect mirror). This mirror can reflect light at all angles and under various polarization conditions like metals; but it does not have the disadvantage of large losses that metals have. The dielectric omnidirectional reflective layer can be produced by nanotechnology, such as self-assembly and sol-gel. Or it can be made by other traditional optical coating methods, such as: sputtering (sputtering), electron gun evaporation (E-gun) or chemical vapor deposition (CVD). Dielectric all-round reflective layer can be designed for a specific beam exit angle, and has high reflectivity for different electric field polarizations (polarizations). Take the periodic multilayer structure formed by SiO2/Al2O3 as an example, and then according to the above The design theory controls the material ratio of the coating film, so that the reflectance of the dielectric all-round reflection layer for ultraviolet light in a specific wavelength range is greater than 95%.

The fluorescent layer 207 on the dielectric omni-directional reflective layer 205 is usually composed of two substances, one is a host compound and the other is a dopant activator, wherein the host material includes sulfate, containing Halophosphates, phosphates, silicates, tungstates and aluminates or inorganic fluorescent materials. The inorganic fluorescent material includes Y2O3, YVO4, SrB4O7F or MgGa2O4; the other dopant includes manganese, copper, mercury or transition metals in lanthanides. The dopant usually enters the crystal lattice of the host material in a substitutional or interstitial manner to adjust the emission wavelength of the host material. The emission color can be determined by the material selection of the dopant. Rare earth elements (rare- earth elements) are also common adulterants.

The cavity of the fluorescent tube is filled with a mixed gas such as mercury and inert gas, or it can be pure inert gas without mercury. When the electrodes 203a and 203b of the fluorescent tube are energized, high-energy electrons and the inert gas in the tube or mixed with mercury are generated. The gas excites part of visible light and part of ultraviolet light, wherein the ultraviolet light 209 can be absorbed by the fluorescent layer 207 to emit visible light 211 , but part of the ultraviolet light 209 passes through the fluorescent layer 207 without interacting with the fluorescent layer 207 . Because the all-round dielectric reflective layer 205 of the present invention is located between the fluorescent layer 207 and the transparent lamp tube, it can reflect the ultraviolet light that has not interacted with the fluorescent layer 207 back into the fluorescent lamp tube 200, and confine the ultraviolet light in the fluorescent lamp tube 200, thereby improving the utilization rate of ultraviolet light, increasing the brightness and luminous efficiency of fluorescent lamps, and avoiding the waste of ultraviolet light passing through the fluorescent layer and transparent lamp tube and causing damage to users' eyes.

Fig. 3 shows the side view of the flat lamp 300 of the present invention, including a first substrate 301 and a second substrate 303, corresponding to the first substrate 301, wherein at least one of the first substrate 301 and the second substrate 303 is a transparent substrate, Such as glass substrate or transparent plastic, and the first and second substrates can be the same material or different materials. There are a plurality of spacers 305 between the first substrate 301 and the second substrate 303, and a plurality of cavities 311 are isolated between the first substrate and the second substrate. Although the cavities in the figure are isolated from each other, they are also can communicate with each other, wherein the spacer wall 305 can be integrally formed with the first substrate 301 or the second substrate 303, and can also be formed separately between the first substrate 301 and the second substrate 303, wherein the shape of the spacer wall can be a single strip, Multiple columns or crosses.

The cavity 311 is filled with gas, such as a mixed gas of mercury and an inert gas, or simply an inert gas. There is a fluorescent layer 309 and a dielectric omnidirectional reflective layer 307 on the cavity wall. The dielectric omnidirectional reflective layer 307 Formed between the fluorescent layer 309 and the first substrate 301 or the second substrate 303, it is a periodically stacked reflective layer, such as a stacked structure of at least two materials in SiO2, AlN, ZnO, Al2O3, Ta2O3 or TiO2, It is preferably a periodic stacked structure formed by SiO2/Al2O3. The dielectric omni-directional reflective layer can be formed by various methods, such as: self-assembly method (selfassembly), sol-gel method (sol-gel) or other traditional optical coating methods, such as: sputtering (sputtering), electron gun evaporation (E-gun) or chemical vapor deposition (CVD). The dielectric omnidirectional reflective layer can reflect light beams of specific wavelengths, and has high reflectivity for different electric field polarizations. Taking the periodic multilayer structure formed by SiO2/Al2O3 as an example, for specific wavelengths Range of ultraviolet light, its reflectivity is greater than 95%.

The light-emitting principle of the planar lamp 300 is similar to that of the fluorescent tube 200. The high-energy electrons generated by the electrodes (not shown) of the planar lamp 300 interact with the gas in the cavity to generate visible light and ultraviolet light. The dielectric omni-directional reflective layer 307 allows visible light to pass through and Reflecting ultraviolet light, its reflectivity is about 95%, can effectively confine the ultraviolet light 209 in the cavity 311, fully react with the fluorescent layer 309 to release the visible light 211, improve the utilization rate of the ultraviolet light 209, and increase the brightness of the flat lamp 300 And luminous efficiency, also can avoid the ultraviolet light to pass through the fluorescent layer 309 and the first substrate 301 or the second substrate 303 to cause waste and be harmful to the eyes of the user.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person in the industry may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope should be determined by what is defined in the claims.

Claims (17)

1. A fluorescent lamp, comprising: A transparent lamp tube with a closed cavity filled with gas; a pair of electrodes arranged at both ends of the transparent lamp tube; A dielectric all-round reflective layer is placed on the inner wall of the transparent lamp tube to confine the ultraviolet light in the closed cavity; and A fluorescent layer is placed on the omnidirectional reflective layer of dielectric material to react with ultraviolet light to generate visible light. 2. The fluorescent lamp according to claim 1, wherein the dielectric omni-directional reflective layer is used to completely reflect ultraviolet light under various polarization conditions. 3. The fluorescent tube according to claim 1, wherein the gas inside the transparent tube is an inert gas or a mixture of mercury and inert gas. 4. The fluorescent tube according to claim 1, wherein the pair of electrodes is disposed inside or outside the transparent tube. 5. The fluorescent tube according to claim 1, wherein the dielectric omni-directional reflective layer is a periodic multi-layer transparent structure. 6. The fluorescent lamp tube according to claim 1, wherein the dielectric omni-directional reflective layer comprises repeated stacks of at least two of the following materials: SiO2, AlN, ZnO, Al2O3, Ta2O3 or TiO2. 7. The fluorescent tube according to claim 1, wherein the dielectric omnidirectional reflective layer is a periodic multilayer structure formed of silicon oxide/aluminum oxide. 8. The fluorescent lamp according to claim 1, wherein the reflectivity of the dielectric omni-directional reflective layer to ultraviolet light is greater than 95%. 9. A plane lamp, comprising: a first substrate; a second substrate, opposite to the first substrate, wherein at least one of the first and second substrates is a transparent substrate; At least one spacer, placed between the first substrate and the second substrate, forms a plurality of gas-filled cavities with the first substrate and the second substrate; a dielectric omnidirectional reflective layer placed on the inner wall of the cavity to confine the ultraviolet light in the cavity; and A fluorescent layer is placed on the omnidirectional reflective layer of dielectric material, which can react with ultraviolet light to generate visible light. 10. The planar lamp according to claim 9, wherein the omnidirectional reflection layer of dielectric material is used to completely reflect ultraviolet light under various polarization conditions. 11. The planar lamp according to claim 9, wherein the spacer is integrally formed with the first substrate or the second substrate. 12. The planar lamp according to claim 9, wherein the shape of the spacer comprises: a single strip, a plurality of columns or a cross. 13. The planar lamp according to claim 9, wherein the gas in the closed cavity is an inert gas or a mixture of mercury and inert gas. 14. The planar lamp according to claim 9, wherein the dielectric omni-directional reflective layer is a periodic multi-layer transparent structure. 15. The planar lamp according to claim 9, wherein the dielectric omni-directional reflective layer comprises repeated stacks of at least two of the following materials: SiO2, AlN, ZnO, Al2O3, Ta2O3 or TiO2. 16. The planar lamp according to claim 9, wherein the dielectric omnidirectional reflective layer is a periodic multilayer structure formed of silicon oxide/aluminum oxide. 17. The planar lamp according to claim 9, wherein the reflectivity of the dielectric omni-directional reflective layer to ultraviolet light is greater than 95%.

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