TW201301328A - Field emission lighting arrangement - Google Patents

Abstract

The present invention relates to a field emission lighting arrangement, comprising an evacuated envelope inside of which an anode structure comprising a phosphor layer and a field emission cathode are arranged, the anode structure being configured to receive electrons emitted by the field emission cathode and to generate light when a voltage is applied between the anode structure and the field emission cathode, wherein the evacuated envelope comprises a light exit portion and a light reflective portion being adapted to reflect light generated at the anode structure, and the field emission lighting arrangement further comprises a heat sink arranged outside of the evacuated envelope and thermally coupled to the light reflective portion. Advantages with the invention includes increase lifetime of the field emission lighting arrangement.

Description

Field emission illuminating device

The present invention is related to an improved field emission illuminating device. More specifically, the present invention relates to a field emission illuminating device that has been adapted to enhance heat dissipation during operation.

There is currently a trend to replace traditional light bulbs with more energy efficient alternatives. Fluorescent light sources (which also have a similar form to conventional light bulbs) are known and are commonly referred to as Compact Fluorescent Lamps (CFLs). As is well known, all fluorescent light sources contain a small amount of mercury exposure, which has the problem of health effects due to mercury exposure. In addition, due to the strict regulations on mercury disposal, the recovery of fluorescent light sources becomes complicated and expensive.

Accordingly, there is a need to provide an alternative to a fluorescent light source. An example of such an alternative is described in WO 2005074006, which discloses a field emission source that does not contain mercury or any other hazardous health material. The field emission source includes an anode and a cathode. The anode is composed of a transparent conductive layer and a phosphor layer coated on the inner surface of a cylindrical glass tube. The phosphor emits light when excited by electrons, and electron emission is generated by a voltage between the anode and the cathode. In order to achieve high illumination, it is desirable to be able to apply a voltage in the range of 4 to 12 kV.

The field emission source disclosed in WO 2005074006 provides a reliable way to provide more environmentally friendly illumination, for example because mercury is not required; however, in order to extend the useful life and/or to increase the illumination efficiency of the bulb, there is always a need for improvement. Light bulb design.

The field emission illuminating device of the prior art is generally configured such that during operation, the cathode emits electrons, which accelerate toward the field emission illuminating device. Place the complete phosphor layer. The phosphor layer provides illumination when the emitted electrons collide with the phosphor particles. The luminescence process is accompanied by the generation of heat, which reduces the lifetime of the field emission illuminator.

According to one aspect of the present invention, a field emission illuminating device is at least partially in accordance with the above, and includes an evacuated envelope in which an anode structure and a field emission cathode are disposed, wherein the anode is disposed The structure includes a phosphor layer configured to receive electrons emitted by the field emission cathode and generate light when a voltage is applied between the anode structure and the field emission cathode, wherein the clearance envelope comprises a a light emitting portion and a light reflecting portion for reflecting light generated in the anode structure, and the field emission light emitting device further comprises a heat sink disposed outside the air filter and thermally coupled to the light reflecting portion .

In contrast to prior art field emission illuminators, field emission illuminators in accordance with the present invention are configured such that light generated during operation of the field emission illuminator can be reflected out of the field emission illuminator through a light exit. This can be achieved by providing a light reflecting portion that has a dual purpose, which simultaneously reflects light and is thermally coupled to a heat sink to dissipate heat generated during illumination.

Preferably, the light reflecting portion is disposed adjacent to the anode structure, for example, as an adjacent layer of the phosphor layer in the anode structure, or disposed outside the wave seal but close to the contact wave seal, thereby providing direct or Indirect thermal coupling. According to the present invention, the heat generated at the anode structure can be independently dispersed by a heat transfer path from the phosphor layer, passed through the light reflecting portion, and dispersed by a heat sink thermally coupled to the light reflecting portion. . By dissipating the heat generated during operation of the field emission illuminator, it can be reduced The temperature of the anode structure phosphor layer, which thus provides the advantage of increasing the lifetime of the field emission illuminator, can also reduce the cost of illumination for the end user, as the rate of replacement of the field emission illuminator can be slower.

In a specific embodiment, the heat sink is configured to reflect light generated at the anode structure through the light exit portion out of the clear wave envelope. Therefore, in this embodiment, both the reflective function and the heat sink are disposed outside the wave seal and can be provided as a single member.

In another embodiment, the anode structure is alternatively configured to reflect light generated at the anode structure out of the clear wave envelope, through the light exit portion, thereby providing a reflective function inside the wave seal and providing heat dissipation outside the wave seal Device. The reflective anode structure can, for example, comprise a metal layer disposed within the wave seal, such as one of aluminum, or aluminum, or other metallic material deposited on the inner surface of the wave seal.

The heat sink can be selected from a plurality of conventional heat sink materials and can be constructed in any suitable form. However, in one embodiment, the heat sink comprises a heat dissipating carbon compound that can be pressurized to one of the appropriate forms to match the form of the field emission illuminating device.

Preferably, the field emission illuminating device further comprises a power supply connected to the field emission cathode and anode structure and configured to provide a driving signal to activate the field emission illuminating device.

Depending on the structure of the field emission illuminating device, and once the choice of cathode and anode materials is determined, the configuration and physical dimensions of the field emission illuminating device are determined; the physical properties of the field emission illuminating device can also be determined. From a circuit point of view, some of these properties are identical to those of electronic components such as diodes with predetermined resistance, capacitance and inductance, capacitors and inductors. Therefore, the field emission illuminating device is shown as being similar to these members in a different manner as a whole, and the most important one is a resonant circuit under different driving conditions, such as DC driving, low frequency driving, and resonant frequency driving. Any frequency below the resonant frequency is defined as a low frequency. By adjusting the capacitance and/or inductance inside and/or outside the bulb, the desired predetermined (resonant) frequency and the phase relationship between the input voltage and the current can be selected. It is further disclosed by the Applicant in EP 09180155, which is incorporated herein by reference. Therefore, it is preferable to select a predetermined frequency so as to fall within a range corresponding to the resonance half power width of the field emission light-emitting device.

Alternatively, the predetermined frequency may be selected according to the luminescence decay rate of the phosphor layer. In general, the luminescence decay rate of a phosphor layer suitable for use in a field emission device occurs in the microsecond range and thus represents a high predetermined frequency. The predetermined frequency is preferably selected to be higher than 10 kHz, and preferably higher than 30 kHz, in consideration of heat generated by luminescence.

Preferably, the wave seal is made of glass and the voltage is preferably in the range of 2-12 kV. In addition, the power supply can be electrically connected, or physically in contact with the field emission device, such as, for example, at a socket/base/side (in the case where the field emission device is a field emission source), or placed in a field emission device nearby.

At the same time, the field emission illumination device can be tightly integrated into a single component, such as a lighting fixture, or a backlight of the display. Furthermore, the field emission illuminating device according to the invention is preferably formed as part of any application requiring illumination, for example comprising a field emission display, an X-ray source.

Other features and advantages of the present invention will be apparent from the description of the appended claims. It will be appreciated by those skilled in the art that the various features of the present invention may be combined to form specific embodiments without departing from the scope of the invention.

The invention will now be described more fully hereinafter with reference to the appended claims, However, the present invention may be embodied in a variety of different forms and should not be construed as being limited to the specific embodiments set forth herein. Instead, these specific embodiments are intended to provide a Provided within the scope of the invention. The same component symbols represent the same components throughout.

Referring now to the drawings, and in particular to the first drawings, a field emission illumination device 100 is illustrated. The field emission illuminating device 100 is based on the concept of using a transparent field emission anode (e.g., an ITO layer 102) disposed on a transparent wave seal (e.g., a clear cylindrical glass tube 104 (wave seal)). To emit light, a phosphor layer 106 is attached to the interior of the ITO layer 102 opposite the field emitter cathode 108. The field emission cathode 108 comprises a base structure with a plurality of sharp edges disposed on the base structure; for example, the ZnO emitter structure disclosed in the applicant's EP 10 159 139, which is incorporated herein by reference.

During operation of the field emission illuminating device 100, an electric field is applied between the cathode 108 and an anode structure (e.g., transparent ITO layer 102, which acts as an electrode), such as by a control unit and power supply (not shown). The way to go. By application of an electric field, the cathode 108 emits electrons that are accelerated toward the phosphor layer 106 of the anode structure. When the emitted electrons collide with the phosphor particles of the phosphor layer 106, the phosphor layer 106 provides illumination. Light from the phosphor layer 106 will pass through the transparent ITO/anode structure 102 and a glass cylinder 104 (as the substrate for the anode structure). The light is preferably white, but of course it can also be colored light. Light can also be UV light.

Turning now to the second figure, a presently preferred embodiment of a field emission illuminating device 200 is illustrated. The field emission illuminating device 200 has the similarity of the field emission illuminating device 100 of the first figure, but is used for field emission. The light device 200 achieves a higher degree of heat dissipation during operation, thereby increasing its useful life. The main difference between the field emission illuminating device 200 and the field emission illuminating device 100 of the first figure is that the field emission illuminating device 200 is provided with a heat sink 204, for example comprising a heat sink flange 206. The heat sink 204 is configured, for example, to surround a portion of the glass cylinder 104, thereby being thermally coupled to each other.

Further, in the field emission light-emitting device 200, only a portion of the glass cylinder 104 is provided with an anode structure, whereby a portion of the glass cylinder 104 is formed to extract light generated by the field emission light-emitting device 200 during operation. Preferably, the glass cylinder 104 provided with the portion of the anode structure is coincident with the glass cylinder 104 thermally coupled to the portion of the heat sink 204. In one embodiment, the glass cylinder 104 thermally coupled to the portion of the heat sink 204 is about 1/3 to 1/2 of the circumference of the glass cylinder 104. Of course, other configurations are also possible, all of which fall within the scope of the present invention.

Another difference between the field emission illuminating device 200 and the field emission illuminating device 100 of the first figure is that the ITO electrode layer 102 has been replaced by a reflective anode electrode 202, for example in the form of a metal layer, such as aluminum. And disposed on the inside of the glass cylinder 104. During operation of the field emission illuminating device 200, electrons emitted from the cathode 108 will operate toward the reflective anode electrode 202 to strike the phosphor layer 106 to emit light. Light will be reflected by the reflective anode electrode 202 toward the exterior of the field emission illuminating device 200. During operation of field emission illuminator 200, heat generated at phosphor layer 106 and reflective anode electrode 202 will be dissipated, at least in part, by heat coupling to heat sink 204 and heat sink flange 206 of glass cylinder 104. The reflective anode structure 202 can be made of a highly reflective metal layer, such as aluminum.

In an alternative embodiment of the invention, and as in the third figure As described in the emissive illumination device 300, a transparent anode structure 302 (e.g., an ITO layer) is again used. Thus, unlike the use of a reflective anode structure in the second figure, light generated during operation of the field emission illuminating device 300 will be able to exit and couple toward the heat sink 204. However, the heat sink 204 is provided with a reflective layer 304 that reflects light toward the side opposite the heat sink 204. The reflective layer 304 can be disposed, for example, on a heat dissipating carbon compound, for example, to the heat sink 204. However, reflective layer 304 can be, for example, an integral part of a metal heat sink. Of course other possibilities are also possible and can be quickly understood by those skilled in the art.

Although the present invention has been described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various alternatives, modifications, and the like. A person skilled in the art can also implement the claimed invention from the following description of the drawings, the description and the appended claims. For example, although specific embodiments of the invention are provided in the form of a cylindrical field emission illuminating device, other forms are of course also possible and fall within the scope of the invention, for example including field emission luminescence at multiple angles. Device. In addition, in the scope of the patent application, the term "comprising" does not exclude other elements or steps, and the term "a" (a, an) does not recite a plural.

100‧‧ ‧ field emission illuminator

102‧‧‧ITO layer

104‧‧‧Clean cylindrical glass tube

106‧‧‧Fluorescent layer

108‧‧ ‧ field emission cathode

200‧‧ ‧ field emission illuminator

202‧‧‧Reflective anode electrode

202‧‧‧Reflective anode structure

204‧‧‧heatsink

206‧‧‧ Radiator flange

300‧‧ ‧ field emission illuminating device

302‧‧‧Transparent anode structure

304‧‧‧reflective layer

The various aspects of the present invention, including the specific features and advantages thereof, can be quickly understood from the foregoing description and the accompanying drawings, wherein: FIG. 1 illustrates a field emission illuminating device in the prior art; A presently preferred embodiment of a field emission illuminator; the third diagram illustrates an alternate embodiment of a field emission illuminator.

104‧‧‧Draining cylindrical glass tube

106‧‧‧Fluorescent layer

108‧‧ ‧ field emission cathode

200‧‧ ‧ field emission illuminator

202‧‧‧Reflective anode electrode

202‧‧‧Reflective anode structure

204‧‧‧heatsink

206‧‧‧ Radiator flange

Claims (12)

A field emission illuminating device comprising a clean air wave envelope, wherein an anode structure and a field emission cathode are disposed inside the slewing wave seal, wherein the anode structure comprises a phosphor layer, the anode structure being configured to be applied at a voltage Receiving electrons emitted by the field emission cathode and generating light between the anode structure and the field emission cathode; wherein the clearance envelope comprises a light emitting portion and a light reflecting portion for reflecting the anode structure And the field emission illuminating device further comprises a heat sink disposed outside the clearing wave envelope and thermally coupled to the light reflecting portion. The field emission illuminating device of claim 1, wherein the light reflecting portion is disposed substantially opposite to the light emitting portion. A field emission illuminating device according to claim 1 or 2, wherein the anode structure is thermally coupled to the light reflecting portion. A field emission illuminating device according to any one of the preceding claims, wherein the heat sink is configured to reflect light generated at the anode structure such that light passes through the light exit portion and is ejected from the clear wave envelope. The field emission illuminating device of any one of clauses 1 to 3, wherein the anode structure is configured to reflect light generated at the anode structure, such that light passes through the light exiting portion from the clearing wave Sealed out. The field emission illuminating device of claim 5, wherein the anode structure further comprises a metal layer disposed inside the wave seal. The field emission illuminating device of claim 6, wherein the metal layer comprises one of aluminum or aluminum. A field emission light-emitting device according to any one of the preceding claims, wherein the heat sink comprises a heat-dissipating carbon compound and/or a mixture thereof. A field emission illuminating device according to any one of the preceding claims, further A power supply is coupled to the field emission cathode and the anode structure and configured to provide a drive signal to activate the field emission illumination device. A field emission illuminating device according to any of the preceding claims, wherein the field emission illuminating device is included in at least one of a field emission source, a field emission display, and an X-ray source. The field emission illuminating device of claim 10, wherein the driving signal for activating the first field emission illuminating device has a predetermined frequency, the predetermined frequency being selected based on an emission attenuation rate of the phosphor layer . The field emission illuminating device of claim 11, wherein the predetermined frequency is higher than 10 kHz, preferably higher than 30 kHz.