US 4,200,794 A · Micro lens array and micro deflector assembly for fly's eye electron beam tubes using silicon components and techniques of fabrication and assembly

Abstract

A combined fine focusing micro lens array and micro deflector assembly for use in electron beam tubes of the fly's eye type is provided. The assembly comprises a fine focusing micro lens array sub-assembly formed from a plurality of spaced-apart stacked parallel thin planar apertured silicon semiconductor lens plates each having an array of micro lens aperture openings. The lens plates each have highly conductive surfaces and are secured to glass rods for holding the plates in stacked parallel spaced-apart relationship with the apertures axially aligned in parallel. A micro deflector assembly is adjacent to the micro lens array sub-assembly. A micro deflector element axially aligned with each respective fine focusing lens element serves for deflecting an electron beam passing through along orthogonal x-y directional axes of movement normal to the electron beam path. The deflector elements are comprised by two orthogonally arrayed sets of parallel spaced-apart deflector bars with alternate bars of each set of deflector bars being interconnected electrically for common connection to a respective source of fine x-y deflection potential. The thin planar apertured silicon lens plates comprising the micro lens array are held together in stacked parallel assembled relationship by spaced-apart glass support rods whose longitudinal axes extend at right angles to the plates and to which the planar silicon lens plates are secured at their periphery. The two orthogonally arrayed sets of parallel spaced-apart deflection bars forming the sets of micro-deflector elements likewise preferably comprise parallel plates or bars of polycrystalline silicon having a highly conductive metalized surface. The micro deflector bars likewise are held in assembled spaced-apart parallel relationship by respective sets of spaced-apart parallel supporting glass rods whose longitudinal axes extend in a plane parallel to the plane of the deflector bars but at right angles thereto and to which the ends of the deflector bars are thermally bonded. The fine focusing micro lens array and micro deflector sub-assembly thus comprised, are secured together in assembled relation by additional glass support rods being disposed about the outer peripheries of the micro lens and micro deflector sub-assemblies and being secured thereto by thermal bonding such as by fusion.

Claims76

Dependent claims

A combined fine focusing micro lens array and micro deflector assembly for use in electron beam tubes of the fly's eye type comprising a fine focusing micro lens array sub-assembly formed by at least one thin planar apertured lens plate fabricated from silicon semiconductor material and having an array of micro lens aperture openings formed therein by photolithographic semiconductor microcircuit fabrication techniques, the apertured silicon lens plate having highly conductive surfaces and being secured to glass rods for holding the lens plate in parallel spaced-apart relationship relative to the micro deflector assembly with the plane of the lens plate substantially at right angles with respect to an electron beam path passing through the assembly, the apertures in the silicon lens plate being axially aligned along respective longitudinal axes passing through the center of the respective apertures parallel to the electron beam path and comprising an array of fine focusing lens elements, said combined fine focusing micro lens array and micro deflector assembly further including a micro deflector sub-assembly mounted immediately adjacent to said fine focusing micro lens array sub-assembly and defining a honeycomb matrix of sets of orthogonally disposed micro deflector elements there being a set of orthogonally disposed micro deflector elements axially aligned with each respective fine focusing lens element along a respective longitudinal axis for deflecting an electron beam passing through the respective fine focusing micro lens array element along orthogonal x-y directional axes of movement in a plane normal to the electron beam path.

A fine focusing micro lens array sub-assembly for use in electron beam tubes of the fly's eye type comprising at least one thin planar apertured lens plate fabricated from silicon semiconductor material and having a matrix of aperture openings formed therein by photolithographic semiconductor microcircuit fabrication techniques, the apertured silicon lens plate having highly conductive surfaces and being secured near the periphery to glass support rods for holding the plate in parallel spaced-apart relationship with the apertures axially aligned in parallel with a longitudinal axis passing through the center of the plate to form an array of fine focusing lens elements for an electron beam, the glass support rods having the longitudinal axes thereof extending at right angles to the plane of the thin apertured silicon lens plate and being thermally bonded thereto.

A micro deflector sub-assembly for use in electron beam tubes of the fly's eye type comprising a honeycomb matrix of sets of orthogonally disposed micro deflector elements there being a set of orthogonally disposed micro deflector elements axially aligned with each respective electron beam path for deflecting an electron beam along orthogonal x-y directional axes of movement in a plane normal to the electron beam path, said honeycomb matrix of sets of micro deflector elements being comprised by two orthogonally arrayed sets of two interdigited parallel spaced-apart deflector bars which define the respective orthogonally arrayed sets of micro deflector elements with alternate bars of each set of deflector bars being interconnected electrically for common connection to a respective source of fine x-y deflection potential and each of said deflector bars being fabricated from silicon and having a highly conductive surface formed thereon.

The method of fabricating micro lens array plates from round, thin planar single crystalline silicon semiconductor wafers of about 1/2 millimeter thickness or less comprising the steps of:

(a) growing a wet silicon dioxide layer on both flat planar surfaces of the silicon wafer to a thickness of several hundred Angstrom units;
(b) by photolithographic techniques employing a photo-resist and solvent for silicon dioxide form an array of silicon dioxide dots on both surfaces of the silicon wafer where it is desired that aperture openings be formed with the centers of each set of opposing silicon dioxide dots on the opposite surfaces of the silicon wafer being axially aligned on a common axis passing through both centers and perpendicular to the plane of the wafer;
(c) spin coat a boron containing emulsion over both silicon dioxide dotted flat surfaces of the wafer and fire wafer in a nitrogen atmosphere at substantially 1100.degree. C., to thereby grow a heavily boron doped layer of about 2 microns thickness in surface areas of wafer where it is desired that no aperture openings be formed;
(d) remove excess boron containing emulsion in a hydrofluoride bath and remove silicon dioxide dots in a fresh hydrofluoride bath to leave a deep heavily boron doped and highly conductive layer of about 2 microns thickness in those planar surface areas on both sides of the wafer where it is desired that no apertures be formed interspersed with an array of dotted updoped silicon surface areas where it is desired that apertures be formed;
(e) etching the wafer in an etchant comprising a hot pyrocatechol and ethylene diamine bath which attacks the dotted undoped silicon surface areas of the wafer previously protected by the silicon dioxide dots during the boron doping step at a faster differential rate than it attacks the boron doped surface areas;
and
(f) continuing the etching until an array of lens aperture openings of a desired diameter have been formed all the way through the thickness of the wafer by the meeting of the simultaneously etched pockets produced on both sides of the wafer by the differential etching action of the etchant on the dotted undoped silicon surface areas.

4 more elements

The method of fabricating micro lens array plates from round, thin planar single crystalline silicon semiconductor wafers of about 1/2 millimeter thickness comprising the steps of:

(a) growing a wet silicon dioxide layer on one flat planar surface to a thickness of several hundred Angstrom units;
(b) by photolithographic techniques employing a photo resist and solvent for silicon dioxide produce an array of silicon dioxide dots where it is desired that aperture openings be formed on one side only of the wafer;
(c) by photolithographic techniques employing a photo resist and solvent for silicon dioxide produce an enlarged area of unmasked silicon on the backside of the wafer corresponding to the area of desired aperture openings on the first mentioned side while leaving a substantial peripheral area of silicon dioxide masked silicon around the peripheral edges of the wafer;
(d) spin coat a boron containing emulsion over silicon dioxide masked surfaces of both sides of the wafer and fire the wafer in a nitrogen atmosphere at about 1100.degree. C. to thereby grow a heavily boron doped layer of about 2 microns thickness through those surface areas of the wafer where it is desired that no aperture openings be formed;
(e) remove excess boron containing emulsion in a hydrofluoric bath and remove silicon dioxide mask in a fresh hydrofluoric bath to leave a deep heavily doped and highly conductive layer of about 2 microns thickness in those planar surface areas of the wafer where it is desired that no apertures be formed interspersed with an array of dotted undoped silicon surface areas where it is desired that apertures be formed;
(f) etching the wafer in an etchant comprising a hot pyrocatechol and ethylene diamine bath which attacks the undoped silicon surface areas of the wafer previously protected by the silicon dioxide dots during the boron doping step at a faster differential rate than it attacks the boron doped surface areas;
and
(g) continuing the etching action until an array of lens aperture openings of a desired diameter have been formed all the way through the thickness of the wafer by the differential etching action of the etchant on the dotted undoped silicon surface areas while leaving a substantial peripheral portion of the original starting wafer thickness to provide rigidity to the resultant lens plate.

5 more elements

Dependencies are inferred from the claim text.

Micro lens array and micro deflector assembly for fly's eye electron beam tubes using silicon components and techniques of fabrication and assembly

Life of this patent

Micro lens array and micro deflector assembly for fly's eye electron beam tubes using silicon components and techniques of fabrication and assembly

Life of this patent

Abstract

Claims76