CN1003102B - Second-generation zoom image intensifie tube - Google Patents

Abstract

The present invention relates to a second generation zoom image intensifying device which belongs to a vacuum photoelectric imaging device. A focusing pole (2), a zoom pole (3) and a second anode (4) are added between a photoelectric cathode (1) and a correcting pole (5) of an ordinary second generation image intensifying device for replacing an anode (8) of the ordinary image intensifying device; the electron optical amplifying rate of the image intensifying device is changed by changing the potential of the zoom pole (3) and the focusing pole (2); a viewing field, a discrimination rate and brightness gain can also be changed. Thereby, the action distance of a night vision apparatus is extended. The present invention is suitable for night vision apparatuses of a middle distance and a long distance.

Description

Second-generation zoom image intensifie tube

The present invention relates to second-generation zoom image intensifie tube.

The present invention is a kind of vacuum photoelectric imaging device that the radiation image of input can be converted to visible image, and it is used for photoelectric imaging system, particularly in the night vision instrument.

In order to strengthen the brightness of casting image intensifier output elephant, at the image plane place of its electron-optical system a microchannel plate is set, this casting image intensifier be referred to as two generation casting image intensifier.Present two generation casting image intensifier basic structure, specially permit clear 59-214143(as Japan and disclose December 4 1984 date), see accompanying drawing 2, comprising the nearly subsides part of photocathode [1], electrode [2], electrode [3], anode [4], the correction utmost point [5] and microchannel plate [6] and phosphor screen [7] composition." electrode [1] is the light input window that fiber panel constitutes; join with method such as welding encapsulation and electrode [2] in advance " " utilizing argon arc welding respectively with electrode 2 and 3 ... to be hermetically sealed to A ... the position ", therefore, electrode [1], [2], [3] are UNICOMs, be idiostatic, in the casting image intensifier electron optics, be referred to as negative electrode or photocathode.And proofreading and correct between the utmost point [5] and microchannel plate [6] input face has the dead ring device, and both insulate.Because each electrode all applies fixing current potential, thereby form the Potential distribution of determining, so the electro-optical magnification of casting image intensifier is changeless.This decide multiplying power two generation casting image intensifier, its performance all is subjected to certain restriction with using.(Schagen) is pointed as the summer root: " under size, the brightness of the scenery condition different with contrast, need the variable casting image intensifier system of a kind of enlargement ratio, to obtain maximum vision gain.Under low-light, observe, can reduce multiplying power, still can see the coarse detail of scenery with the higher brightness gain clearly; On the other hand,, can improve multiplying power, with coming the more precise and tiny details of observing scene in lower luminance gain and less visual field if brightness increases.This change times casting image intensifier system also has the advantage of an additional practicality: when promptly beginning search and seeking target, and available bigger visual field; Target can improve multiplying power, with the details of less visual field object observing once determining." (Advances in Electronics and Electron Physics, the Vol.X. VI, PP75-84) in addition; for two generation casting image intensifier; if its enlargement ratio is changed, can utilize more channel transferring information, to improve its resolution in greater than 1 scope.

Task of the present invention is a kind of second-generation zoom image intensifie tube of design, and its multiplying power can be changed in greater than 1 scope.When its multiplying power changed, visual field, luminance gain and resolution be respective change also.When the visual field was big, multiplying power was little, gain is high, resolution is lower; Along with dwindling of visual field, multiplying power increases, gain reduces, resolution improves.

For realizing the object of the invention, we comprise photocathode [1] by the second-generation zoom image intensifie tube of invention, electrode I [2], electrode II [3], anode [4], proofread and correct the nearly subsides part that the utmost point [5] and microchannel plate [6] and phosphor screen [7] are formed, it is characterized in that electrode I [2] is the focusing utmost point, between it and photocathode [1] the dead ring device is arranged, so that the current potential of electrode I [2] is adjustable, said electrode II [3] is for becoming times utmost point, between it and electrode I [2] and the anode [4] the dead ring device is arranged also, so that its current potential is adjustable, distance between the change times utmost point [3] and the focusing utmost point [2] is greater than the 4-6 millimeter, the said correction utmost point [5] is a cylindrical shape, and the one end has the contacted elasticity crimping of input face with channel plate [6].

The basic structure of whole second-generation zoom image intensifie tube as shown in Figure 1.The utmost point of wherein focusing is variable with the current potential that becomes times utmost point, by regulating the current potential that becomes times utmost point, changes the electro-optical magnification of casting image intensifier; Simultaneously, correspondingly change the current potential of the focusing utmost point, to realize the optimum focusing under the different magnification ratios.

Optically transparent material manufacturings such as substrate [11] (the claiming input panel again) useable glass of photocathode of the present invention [1] or fibre faceplate, its shape can be the plane, also can be curved surface.When the substrate [11] (input panel) of photocathode [1] was glass planar, its edge resolution was lower, and image plane is away from photocathode [1], and homogeneous tube length increases, but the center resolution is higher.Night vision is adopted the substrate [11] (input panel) of fibre faceplate as photocathode [1] with casting image intensifier more.This panel is a curved surface towards the inner surface of vacuum, generally be sphere, and the outer surface that contacts with atmosphere is the plane.Radius of curvature is more little, and it is good more that the edge resembles matter, and the homogeneous tube contraction in length.

Second-generation zoom image intensifie tube in the accompanying drawing 1, it is characterized in that become between times utmost point [3] and the focusing utmost point [2] distance greater than 4～6 millimeters situation under, increase as far as possible and become times utmost point [3] near the radial dimension of that end of photocathode [1] and the diameter of this end aperture.

Become times utmost point [3] and can be made into flat-top awl or ball addendum cone and other shape, but the easier measurement and positioning of flat-top tapered electrode.When the current potential that becomes times utmost point [3] lower or multiplying power hour, the electric field strength on photocathode [1] surface a little less than, can reduce the resolution of electron-optical system.For improving the electric field strength on photocathode [1] surface, between the change times utmost point [3] and the focusing utmost point [2], do not produce under the condition of discharge, promptly generally should keep becoming between times utmost point [3] and the focusing utmost point [2] at a distance of greater than 4～6 millimeters, should increase the radial dimension of the change times utmost point [3] that end relative as far as possible with photocathode [1].Under different multiplying powers or different Potential distribution, the photoelectronic track of photocathode [1] edge-emission and the intersection point of tube axis scatter along axis.Thereby, can increase the diameter that becomes times utmost point [3] that the end aperture relative with photocathode [1] in order not intercept and capture the photoelectron restriction visual field of these edge-emission.

Second-generation zoom image intensifie tube in the accompanying drawing 1, the utmost point [2] that it is characterized in that focusing can be made into cylindrical shape, at it less thin ring of diameter of a band crotch is arranged near that end that becomes times utmost point [3].

Shape, current potential and the position of the focusing utmost point [2] will and become times utmost point [3] as the unified design of a triode with photocathode [1].The focusing utmost point [2] is made generally in cylindrical shape, at its that end near the change times utmost point [3], the less thin ring of diameter that one band crotch is arranged, this thin ring can draw the equipotential surface between the photocathode [1] and the change times utmost point [3] in, be easy to control the shape of interpolar equipotential surface, it all can be distributed near homocentric sphere in the restricted portion of visual field under different multiplying.

In the accompanying drawing 1, the aperture size of second-generation zoom image intensifie tube anode [4] is greater than becoming the aperture size of times utmost point [3] towards that end of microchannel plate [6].

Anode [4] often is called second plate in becoming times casting image intensifier electron optics.As previously mentioned, the electro-optical magnification of generally wishing second-generation zoom image intensifie tube can expand to the scope greater than 1.Therefore, the radial dimension of second plate [4] should be greater than becoming the radial dimension of times utmost point [3] towards that end of microchannel plate [6], in order to avoid second plate [4] is intercepted and captured the photoelectron of the close field of view edge of being come out by the change times utmost point [3].

The current potential of second plate [4] is higher than the current potential of microchannel plate [6] input.So between forms enough strong rejection field to the cation of being overflowed by microchannel plate [6], in order to avoid cation stream feeds back on the photocathode [1].Otherwise this cation fails to be convened for lack of a quorum and inspire secondary electron on photocathode [1]; These secondary electrons are beaten near the phosphor screen center, can produce parasitic speck.Simultaneously, the current potential of second plate [4] can be lower than the maximum potential that becomes times utmost point [3].Like this, can under the lower situation of the maximum potential that becomes times utmost point [3], reach the maximum of enlargement ratio.

The current potential of proofreading and correct the utmost point [5] should be lower than the current potential of second plate [4], and the photoelectron that is come out by second plate [4] is formed decelerating field, and makes it be subjected to effect to axle power, with assurance photoelectron near vertical focus on the input plane of microchannel plate [6].For structure, technology and the power supply thereof of simplifying casting image intensifier, also but high-ranking officers' positive pole [5] is made cylindrical shape, the one end has the contacted crimping of input face with microchannel plate [6], be communicated with the input face of microchannel plate [6] so proofread and correct the utmost point [5], thereby both current potentials equates.

In a word, concerning second-generation zoom image intensifie tube, must be in specific multiplying power scope, under each multiplying power, the assurance photoelectron can both realized the optimum focusing imaging in full visual field.For this reason, the shape of necessary well-designed each electrode, current potential and position by revising design on computers repeatedly, just can realize satisfactory results.

By the second-generation zoom image intensifie tube that the present invention has made, also have the visual field of change, become characteristics such as resolution and degree of brightening gain.Test result shows, except that photocathode sensitivity, luminance gain, equivalent background input illumination and signal to noise ratio etc. all reach the performance index of deciding multiplying power two generations casting image intensifier, the homogeneous tube electro-optical magnification can change to 2.5 times by 0.8 times, the photocathode effective diameter changes to 11 millimeters by 28 millimeters, and the homogeneous tube resolution is brought up to 70 pairs of line millimeters by 30 pairs of line millimeters.For verifying the result of use of this pipe in night vision instrument, also carried out the resolution test under low contrast, the low-light (level).When the illumination of photocathode input panel [11] is 1.8 * 10 ^-4Lux, the contrast of resolution pattern are *, and the homogeneous tube multiplying power is when changing to 2.5 times by 0.8 times, and the homogeneous tube resolution is brought up to 21 pairs of lines per millimeters by 11 pairs of lines per millimeters.This shows that second-generation zoom image intensifie tube can extend the operating distance of night vision instrument.Therefore, during it is specially adapted to, long-range night vision device.

Fig. 1 is a second-generation zoom image intensifie tube of the present invention, wherein the 1-photocathode; The 2-utmost point of focusing; 3-becomes times utmost point; The 4-second plate; 5-proofreaies and correct the utmost point; The 6-microchannel plate; The 7-phosphor screen; The 11-input panel; The 20-output slab.

Fig. 2 is prior art-common two a generations casting image intensifier, and wherein 1,5,6,7 is identical with explanation among Fig. 1.2-electrode [2], 3-electrode [3], 4-anode.

Fig. 3 is one embodiment of the present of invention.Now the overall process of making by embodiment is introduced its each several part title.The focusing utmost point [2] welds together with oxygen-free copper arm [12] earlier.With the short tube of negative electrode [10], the focusing utmost point [2] becomes times utmost point seat [14] then, and second plate [4] is sealed with the dead ring that sealing-in dish [15] is made by materials such as pottery or glass.In this socket, be respectively charged into become times utmost point [3] and focusing utmost point inner core [13] and put weld after, promptly finish whole socket assembly.Wherein the input panel of using as photocathode [1] substrate [11] and cathode disc [9] low-melting glass scolder sealing-in forms cathode assembly.Equally, also use the eutectic solder sealing-in with screen dish [19], form screen assembly as the output slab [20] that phosphor screen [7] substrate is used.Phosphor screen [7] is a high-strength screen of being made aluminizing by zinc sulphide, cadmium material.Shroud [16], panel seat [17] are sealed with the dead ring that the short tube in back [18] is made by materials such as pottery or glass; Microchannel plate [6] pack into panel seat [17] with after proofreading and correct the utmost point [5] and compressing, again the latter is fixed up with shroud is spot-welded together, thereby forms assembly afterwards.Press Fig. 3, cathode assembly, socket assembly, back assembly and the corresponding cathode disc of screen assembly [9], the short tube of negative electrode [10], sealing-in dish [15], shroud [16], the short tube in back [18] and screen dish [19] to after connecting, are welded together by argon arc welding.After so whole body sealing-in being finished, just it can be connected on and make photocathode [1] on the vacuum system.Photocathode [1] is the polybase negative electrode of being made by antimony, potassium, sodium, four kinds of materials of caesium.After treating that photocathode [1] is finished, body sealed-off on the vacuum system is got off.So far, homogeneous tube manufacturing process finishes.

The current potential of each electrode of second-generation zoom image intensifie tube is allocated as follows: the output head grounding of microchannel plate [6], be zero potential, and the current potential of its input is-the 800--900 volt.The current potential of photocathode [1] is-2400 volts.The current potential of the focusing utmost point [2] is-the 2320--2800 volt.The current potential that becomes times utmost point [3] lies prostrate for-1700-+3000.The current potential of second plate [4] is+1500 volts.It is idiostatic with the input of microchannel plate [6] to proofread and correct the utmost point [5].The current potential of phosphor screen [7] is+4000 volts.

Claims (4)

1, a kind of second-generation zoom image intensifie tube, it is by photocathode [1], electrode I [2], electrode II [3], anode [4], proofread and correct the utmost point [5], microchannel plate [6] and phosphor screen [7] constitute, it is characterized in that electrode I [2] is the focusing utmost point, between it and photocathode [1] the dead ring device is arranged, so that the current potential of electrode I [2] is adjustable, said electrode II [3] is for becoming times utmost point, distance between it and the focusing utmost point [2] is greater than 4～6 millimeters, the current potential of electrode II [3] is also adjustable, the said correction utmost point [5] is a cylindrical shape, and the one end has the contacted elasticity crimping of input face with microchannel plate [6].

2, casting image intensifier according to claim 1, it is characterized in that become between times utmost point [3] and the focusing utmost point [2] distance greater than 4～6 millimeters situations under, increase as far as possible and become times utmost point [3] near the radial dimension of that end of photocathode [1] and the diameter of this end aperture.

3, casting image intensifier according to claim 1, the utmost point [2] that it is characterized in that focusing can be made into cylindrical shape, at it less thin ring of diameter of a band crotch is arranged near that end that becomes times utmost point [3].

4, casting image intensifier according to claim 1, the aperture size that it is characterized in that anode [4] is greater than becoming the aperture size of times utmost point [3] towards that end of microchannel plate [6].