SU748576A1 - Image converter - Google Patents

Description

The invention relates to the field of electronics, in particular, to electron-optical converters (EOC) used in apparatus for recording fast processes.

Known EOP, vyspglnenny in the form of a cylindrical cup with a double bottom. A photocathode is deposited on one base of the cylinder, and a screen on the other. An accelerating voltage is applied between the photocathode and the screen. The electrons emitted from the photocathode under the action of light are transported by the field and an image is built on the screen. In this case, the image can be converted from one region of the spectrum to another.

This image intensifier has a number of significant drawbacks. Since the homogeneous electric field is not an electron lens, the image is defocused on the screen. As a result, the image intensifier has a low resolution. The magnification factor is always 1. It is difficult to use such an image intensifier as an electronic shutter, since the operation in pulsed mode

requires the formation of high-voltage fvlO kV control pulses of short duration, which in itself is a difficult task.

Also known is an electro-optical transducer containing a photocathode, an electrostatic electron lens with an anode diaphragm, observing the electron beam, a shutter system comprising one pair of ground plates and one pair of compensating plates separated by a shutter diaphragm 2.

ts

Image locking is performed by deflecting the electron beam at the gate diaphragm when applying a constant anti-phase bias voltage to the gate and

20 . compensating plates.

The shutter allows you to lock the electron beam when it is deflected both above and below the optical axis of the device. With pulsed power

25, only one direction of deviation is always used.

The unlocking of images takes place when the bias voltage is compensated by a pulse voltage applied to

30 gate and compensating plates in antiphase. Compensating plates to prevent blurring of the image at the moment of supplying the trigger pulse In the open state, during the triggering of the pulse, the photocathode through the slit in the shutter diaphragm freely passes on the screen. One of the main disadvantages of this image intensifier is sufficiently high shutter speed. tv 2 kV. Increases the sensitivity of A thief can be achieved by lengthening or drawing closer the bolt plates, but both will lead to electrons falling on them when they are locked. The electrons reflected from the shutter plates, having passed through the slit of the shutter, call the background illumination of the image intensifier screen. The aim of the invention is to reduce the blocking voltage. To achieve the goal, one i-e slide plates are positioned at an angle tt 0 -arcCOS y to the optical axis of the device, so that in the plane of deflection it coincides with the direct connecting edge of the holes in the anode and gate diaphragms positioned below the optical axis and the second shutter on the plate is set at an angle of 1 6i-at-ccos TG to the optical axis, such that in the plane of deviation coincide with the straight line connecting the opposite edge of the orifice of the anode diaphragm and the point on the gate diaphragm located above the optical axis ; g d, where d is the diameter of the electronic 2 beams In the plane of the shutter diaphragm - the distance between the edges of the anode and gate diaphragm openings located below the optical axis in the plane of deviation of the shutter plates; E „is the distance between the second edge of the anode diaphragm opening and the point on the gate diaphragm located 3 d above the optical axis in the plane of deviation of the shutter plates; E is the distance along; the optical axis between the anode and the shutter diaphragm. The drawing shows the described EOP. The image converter tube contains a photocathode 1, focusing electrolyte 2, anodic diaphragm 3, gate plates 4, a shutter diaphragm 5, compensating plates b, horizontal scan plates 7, vertical scan plates 8, a luminescent screen 9. One of the shutter plates is set at an angle of 6 –ar -ccos -r to ort1 2 of the instrument’s axial axis and in the deflection plane coincides with the direct connecting edge of the anode and gate diaphragm holes located below the optical axis, the second plate is set at an angle & PI -arccos - | g to the optical axis and in the plane tkloneni coincides with the straight connecting the second end of, Verstov anode aperture and a point on the sealing diaphragm disposed above the optical axis j d. The device works as follows. The electron image O of the photocathode formed by an electrostatic lens is transferred through a hole in the anode diaphragm and a slit in the gate diaphragm onto a fluorescent screen. Image locking is performed by shifting the electron beam to the shutter aperture above the optical axis of the device when applying a constant anti-phase bias voltage to the shutter and compensating plates. Unlocking of the image takes place when the bias voltage is compensated by the pulse voltage applied to the gate and compensating plates in the back wall. The image is scanned across the screen when the voltages are applied to the plates of the horizontal and vertical scanning. Thus, the operation of an image intensifier with an asymmetrical shutter is fundamentally no different from the operation of an image intensifier with a symmetric shutter, as described above. The only difference is the need to mark the polarity of the shutter plates; the beam can be deflected to the shutter diaphragm when locking the image; Only push in one direction (up from the optical axis in the drawing). An asymmetrical electronic shutter allows you to increase the length C of the shutter plates, as well as bring them closer together due to the rotation of the plates relative to the optical axis and using space on one side of the optical axis of the device to bring the plates closer together (this space is not used in the IC with a symmetric shutter) ). Shutdown voltage of the EIF PIM-3 l / 2 kV at an anode voltage of 15 kV, Estimated blocking voltage in the image converter tube of the proposed design 0.7 kV at an anode voltage of 15 kV Kenya. The clamp voltage measured on the EO model is 650 V .

Claims (2)

Invention Formula Electro-optical transducer containing f6t6kat one, an electrostatic electron lens with an anode diaphragm, forming an electron beam, a shutter system, including one pair of shutter plates and one pair of compensating plates, separated by a stopper diaphragm, characterized by the fact that one of the slide plates is set at an angle Q orccos p to the optical axis device so that in the plane of deflection it coincides with the straight line connecting the edges of the holes in the anode and gate diaphragms located below the optical axis, and the second bolt plate is set at an angle .-1 GjCircCDS -g-- to the optical axis, so that in the plane of deflection coincides with the straight line connecting the opposite edge of the aperture of the anode diaphragm and the point on the gate diaphragm located above the optical axis I-. Where on E is the distance in the length of the optical axis between the anode and gate diaphragms;  gg is the distance between the edges of the anodic and the gate diaphragms located along the optical axis in the plane of deviation of the gate plates;  the distance between the opposite edge of the anode diaphragm and the point on the gate diaphragm, above the optical axis on five s in the plane of deviation for creative plates d is the diameter of the electron beam in the plane of the shutter diaphragm. 0 Sources of information taken into account in the examination 1. Sherstnev L. R, Electron optics and electron beam devices, M., Energie, 1971, p. 267. 2. Butslov MM Electron-optical converters for studying ultrafast processes. Achievements of scientific photography, v.6, 1959,, 77 (prototype).