CN2731900Y - Field emitting flat light source device and its cathode - Google Patents

Abstract

The utility model relates to a field emission planar light source device, which comprises a cathode with a plurality of emitters. Wherein, the cathode further includes a plurality of conductive bearing columns, and the emitter is distributed on the plurality of conductive bearing columns. The light source device can directly provide planar light without subsequent optical processing, and can be used in multiple fields including information display.

Description

Field emission planar light source device and its cathode

【Technical field】

The utility model relates to a field emission planar light source device, in particular to a field emission cathode.

【Background technique】

Planar light sources are widely used in many fields, especially in the field of information display. A variety of passive display technologies, including liquid crystal displays, require a planar light source that can emit light uniformly as its main component. In the past, optical methods were mostly used to obtain a uniform light-emitting plane. For example, the backlight panel of liquid crystal uses an optical system to defocus the line light source into a plane light source.

Please refer to FIG. 1 , Chinese invention patent application No. 02152111.5 published on June 16, 2004 discloses a backlight source 10 applied to a liquid crystal display. It includes LEDs 12 , a light guide plate 14 and microlenses 16 . Wherein the light guide plate 14 includes a light incident surface (not marked) opposite to the light emitting diode 12, the microlens 16 is arranged between the light emitting diode 12 and the incident surface of the light guide plate 14, and the light emitting diode 12 and the light guide plate 14 The light plate 14 is respectively positioned within the working distance on both sides of the microlens 16, so that the microlens 16 couples the divergent light emitted by the light emitting diode 12 to enter the light guide plate 14 from the incident surface with uniform parallel light, and the light guide plate 14 couples The parallel light is uniformly incident from a parallel light from a plane.

In addition, for related technologies of converting line light sources into planar light sources by using components such as light guide plates, please refer to China No. 02107375.9 published on October 23, 2002, titled "Light pipes, planar light source components and emissive liquid crystal display devices". Invention patent application, and Chinese invention patent application No. 02128659.0 published on February 11, 2004, titled "Plane Light Source Device and Liquid Crystal Display Using It as Backlight Module", etc.

However, the planar light source device working in this conversion mode cannot directly obtain planar light, and must be obtained by subsequent optical processing. Moreover, it is also necessary to assemble precision-processed optical components, such as the above-mentioned microlenses, light guide plates, etc., thereby increasing the cost of this part of the optical components and increasing the production cost.

At present, the industry also utilizes the field emission effect to manufacture light source devices. Its main working principle is: when the cathode is at a lower potential than the anode or grid, the surface of the cathode has an electric field pointing to the anode or grid. If the electric field strength is sufficient, the cathode starts to emit electrons, and these electrons reach the anode under the action of the anode electric field. , bombard the phosphor attached to the anode, so that the phosphor undergoes energy level transition and emits light. Compared with the previous technology, especially the fluorescent tube, this field emission light source only needs to evacuate the cathode and anode without filling any gas, such as mercury and other harmful gases, and will not cause environmental pollution.

In US Patent No. 6,008,575 issued on December 28, 1999, Vitaly et al. disclosed a light source device using a field emission cathode. The field emission cathode includes a substrate and a plurality of emitters extending from the substrate. However, the light source device is a tubular device, which can only provide linear light source, and still cannot directly provide plane light.

Therefore, it is necessary to provide a field emission planar light source device and its cathode that can directly provide planar light.

【Content of utility model】

In order to solve the problem that the light source device in the prior art cannot directly provide planar light, the purpose of this utility model is to provide a field emission planar light source device that can directly provide planar light.

Another object of the present invention is to provide a field emission cathode that can be applied to the field emission planar light source device.

To achieve the above object, the utility model provides a field emission planar light source device, which includes a cathode with a plurality of emitters. Wherein, the cathode further includes a plurality of conductive bearing columns, and the emitter is distributed on the plurality of conductive bearing columns.

The device may further include an anode opposite the cathode.

In addition, the device may further include two anodes, and the cathode is located between the two anodes.

Wherein, the above-mentioned emitter is formed on the surface of the conductive bearing column facing the anode, and its material can be selected from metals, non-metals, compounds and one-dimensional nanomaterials. The emitter has an end, which preferably faces away from the conductive support post along the normal to the surface of the conductive support post. The above-mentioned conductive supporting pillars can be cylindrical or prismatic, preferably distributed in parallel on the same plane. Tension means are preferably provided at the end of at least one of the conductive carrying posts. A grid can be further arranged between the cathode and the anode.

To achieve another purpose, the utility model also provides a field emission cathode, which includes a substrate and an emitter formed on the substrate. Wherein, the base body includes a plurality of parallel conductive bearing pillars, and the emitter is distributed on the conductive bearing pillars.

Compared with the prior art, the utility model arranges a number of conductive carrying columns distributed with emitters in parallel to form a cathode emitter array, and the emitter emits electrons under the action of an electric field to bombard the anode fluorescent layer to make it emit light, thus eliminating the need for additional optical elements Perform optical processing to directly provide planar light.

At the same time, when the emitters are arranged along the normal direction of the surface, the shielding effect between the emitters will be significantly reduced, thereby improving the electron emission efficiency of the field emission cathode, improving the photoelectric conversion efficiency, and improving the performance of the entire light source device. In addition, the utility model also proposes that one or both ends of the conductive supporting column be tightened and fixed by tensioning devices such as springs, which can ensure the uniformity of electron emission on the one hand, and make it more stable on the other hand, thereby increasing the overall light source. The service life of the device.

【Description of drawings】

FIG. 1 is a schematic diagram of a traditional planar light source device applied to a liquid crystal display in the prior art;

Fig. 2 is the three-dimensional schematic view of the single-sided field emission planar light source device provided by the utility model;

Fig. 3 is a sectional view along line III-III in Fig. 2;

Fig. 4 is a sectional view along line IV-IV in Fig. 2;

Fig. 5 is a three-dimensional schematic diagram of a double-sided field emission planar light source device provided by the present invention;

Fig. 6 is a sectional view along line VI-VI in Fig. 5;

Fig. 7 is a sectional view along line VII-VII in Fig. 5 .

【Detailed ways】

The utility model will be described in further detail below in conjunction with accompanying drawing.

Please refer to FIGS. 2 to 4 together. The first embodiment of the present invention is a single-sided field emission planar light source device 8 . It includes a bottom plate 80 , a cathode 81 and an anode 82 . The three are basically parallel to each other, and the four sides are sealed by glass and evacuated into a vacuum state.

Wherein, several glass pillars 84 are provided between the bottom plate 80 and the anode 82 to support the whole device 8 . Both ends of the bottom plate 80 are also provided with cathode fixing plates 89 for fixing the cathode 81 .

The cathode 81 includes a plurality of conductive supporting pillars 812 and a plurality of emitters (not shown). The emitters are evenly distributed on the surface of each conductive support post 812 opposite to the anode 82 . The end used for emitting electrons is away from the conductive bearing pillar 812, and preferably distributed along the normal direction of the surface of the conductive bearing pillar, so as to reduce the shielding effect between the emitters. The plurality of conductive supporting pillars 812 are cylindrical, uniformly arranged at certain intervals, and parallel to each other to form a cathode emitter array. Preferably, the shapes and sizes of the conductive supporting pillars 812 are uniform, and their central axes are basically distributed on the same plane, so they can be approximately regarded as an electron emission plane. The cathode lead wires 85 are disposed on one side of the cathode 81 and respectively connected to one end of each conductive support column 812 .

The anode 82 is a piece of flat glass with a transparent conductive film (not shown) and a fluorescent layer 83 formed on its surface. Wherein, the fluorescent layer 83 may contain red, green and yellow fluorescent powders, which preferably correspond to the positions of the conductive supporting pillars 812 of the cathode 81 and are distributed in stripes. In addition, the fluorescent layer 83 may also contain white fluorescent powder, covering the entire surface of the anode 82 opposite to the cathode 81 . One side of the anode 82 is also provided with an anode lead 86 connected to the transparent conductive film. It should be noted that the brightness of the device 8 will mainly depend on factors such as the voltage and current density of the anode 82 and the luminous efficiency of the phosphor, which can be properly arranged according to different application needs.

The side wall glass of the device 8 has an exhaust hole (not marked), and is connected with an exhaust pipe 87 . A getter 88 is placed on the inner wall of the exhaust pipe 87 to maintain the vacuum in the device 8 .

In this embodiment, the conductive bearing pillar 812 is a filament structure. The emitter is formed on the surface of the conductive supporting pillar 812 by means of electrophoresis or chemical vapor deposition. These conductive supporting pillars 812 formed with emitters are evenly arranged and fixed on the cathode fixing plate 89 to form the cathode 81 . Certainly, the conductive bearing pillars 812 can also be arranged and fixed on a substrate first, and then the emitter is formed on the conductive bearing pillars 812 by the above-mentioned method.

At the same time, the emitter can be a variety of microtip structures, including metal tips, non-metallic tips, compound tips and one-dimensional nanomaterials, such as tungsten tips, molybdenum tips, silicon tips, diamond tips, zinc oxide tips, etc. One-dimensional nanomaterials include various nanoscale tubular structures, rod structures and wire structures, such as carbon nanotubes, silicon wires, and molybdenum wires.

It should be noted that a grid, such as a metal grid formed by photolithography, can be added between the cathode 81 and the anode 82 as needed, so as to improve the electron emission efficiency of the cathode 81 .

Please refer to FIG. 5 to FIG. 7 together. The second embodiment of the present invention is a double-sided field emission planar light source device 9 . The main difference between it and the previous embodiment is: the device 9 includes two anodes 90, 92, the cathode 91 is located between the two anodes 90, 92, and each conductive support column 912 forming the cathode 91 faces the anode 90, Emitters (not shown) are formed on both sides of the surface of 92 .

In addition, in this embodiment, one end of the conductive bearing column 912 is fixed to the cathode fixing plate (not shown) by a spring 94, so as to tighten the conductive bearing column 912 so that it is not easy to bend, so that these conductive bearing columns 912 can Better to be on the same plane. Optionally, springs 94 may be provided at both ends of the conductive bearing column 912 to enhance the tensioning effect.

Those of ordinary skill in the art can understand that, besides the pointed out cylindrical shape, the described conductive support pillars can also be other types of pillar structures, such as quadrangular prisms, pentagonal prisms or irregular polygonal pillars, instead of using Specific examples are limited. Moreover, other elements or devices can also be used to tension the conductive bearing column, not limited to the spring. In addition, the number, fixing method and arrangement position of the cathode and anode lead wires can be changed according to actual needs. Of course, these changes made according to the spirit of the utility model should be included in the protection scope of the utility model.

The utility model arranges a plurality of conductive carrying columns distributed with emitters in parallel to form a cathode emitter array, and the emitter emits electrons under the action of an electric field to bombard the anode fluorescent layer to make it emit light, thereby directly providing flat light.

At the same time, when the emitters are arranged along the normal direction of the surface, the shielding effect between the emitters will be significantly reduced, thereby improving the electron emission efficiency of the field emission cathode, improving the photoelectric conversion efficiency, and improving the performance of the entire light source device. In addition, the utility model also proposes that one or both ends of the conductive supporting column be tightened and fixed by tensioning devices such as springs, which can ensure the uniformity of electron emission on the one hand, and make it more stable on the other hand, thereby increasing the overall light source. The service life of the device.

Claims (10)

1. A field emission planar light source device, comprising a cathode with a plurality of emitters, characterized in that the cathode further includes a plurality of conductive bearing columns, and the emitters are distributed on the plurality of conductive bearing columns. 2. The field emission planar light source device as claimed in claim 1, further comprising an anode opposite to the cathode. 3. The field emission planar light source device according to claim 1, characterized in that the device further comprises two anodes, and the cathode is located between the two anodes. 4. The field emission planar light source device according to claim 2 or 3, characterized in that a grid is provided between the cathode and the anode. 5. The field emission planar light source device according to any one of claims 1 to 3, characterized in that, the plurality of conductive carrying columns are distributed in parallel on the same plane. 6. The field emission planar light source device according to any one of claims 1 to 3, wherein the emitter material is selected from metals, non-metals, compounds and one-dimensional nanomaterials. 7. The field emission planar light source device according to any one of claims 1 to 3, wherein the emitter has an end, which faces away from the conductive bearing column along the normal line of the surface of the conductive bearing column. direction. 8. The field emission planar light source device according to any one of claims 1 to 3, characterized in that at least one end of the conductive supporting column is provided with a tensioning device. 9. The field emission planar light source device according to any one of claims 1 to 3, characterized in that, the conductive supporting column is cylindrical or prismatic. 10. A field emission cathode, comprising a base body and several emitters formed on the base body, characterized in that the base body includes a number of parallel conductive bearing pillars, and the conductive bearing pillars are distributed with the emitters.

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