# US 12,002,255 B1 · Microfabricated vacuum photodiode arrays for solar power > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,255 B1 - Document ID: US12002255B1 - Status: Granted - Kind: B1 - Application number: 17/033,916 - Filed: 2020-09-27 - Granted: 2024-06-04 - Earliest claimed: 2014-03-11 - Assignees: nVizix LLC - Applicants: nVizix LLC - Inventors: David Roberts Winn - Web page: https://patentgrep.com/patent/US12002255B1 ## CPC - H02S 99/00: Subject matter not provided for in other groups of this subclass - H10F 19/80: Encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells - G06T 5/50: using two or more images, e.g. averaging or subtraction - G06T 5/94: based on local image properties, e.g. for local contrast enhancement - G06V 10/44: Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components - G06V 10/758: {Involving statistics of pixels or of feature values, e.g. histogram matching} - G09G 5/10: Intensity circuits - H01J 40/16: having photo- emissive cathode, e.g. alkaline photoelectric cell (operating with secondary emission H01J43/00) - H10F 10/10: having potential barriers - H10F 19/31: having multiple laterally adjacent thin-film photovoltaic cells deposited on the same substrate - H10F 77/413: {directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42)} - H10F 77/48: Back surface reflectors [BSR] - G06T 2207/10016: Video; Image sequence - G06T 2207/20216: Image averaging - G09G 2320/0257: Reduction of after-image effects - Y02E 10/50: Photovoltaic [PV] energy - H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00) - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A system and method are presented for the design and fabrication of arrays of vacuum photodiodes for application to solar power generation. In a preferred embodiment, each photodiode cell comprises a microfabricated enclosure with a hermetically sealed vacuum, an absorptive photocathode, and a transparent anode, wherein the photocathode and the anode are separated by a vacuum gap of less than about 20 micrometers. Light incident on the photocathode through the anode leads to a flux of electrons passing from the photocathode across the vacuum gap to the anode. In a further preferred embodiment, the photocathode is backed by a reflection layer with, e.g., controlled diffuse reflection, thus increasing the efficiency of energy extraction. An array of such cells may be manufactured using automated thin-film deposition and micromachining techniques. ## Claims ### Claim 1 A method of manufacturing a solar photovoltaic panel, comprising: micropatterning a surface of a support to provide micron scale roughness; depositing a reflection layer on the micropatterned surface; depositing a multialkali photocathode layer comprising at least one of cesium, sodium, potassium, and antimony on the reflection layer; providing a micromachined window partitioned into a regular array of separated cells, having an inner surface coated with a transparent conducting anode layer; and sealing the micromachined window to the support under vacuum, to define an array comprising a plurality of respective isolated vacuum spaces of the solar photovoltaic panel, wherein the solar photovoltaic panel is adapted to produce a current of greater than 230 A/m2 at a load voltage of at least 1 V under solar illumination of 1000 W/m2. ### Claim 2 (depends on 1) The method according to claim 1, wherein: wherein the micromachined window is transparent to optical and infrared photons; further comprising coating an inner surface of the micromachined window of each respective vacuum space with the transparent conducting anode layer, configured to collect electrons from a respective vacuum space; and maintaining the photocathode layer formed on the reflection layer opposite to the respective portion of the window across a respective isolated vacuum space, spaced from the transparent conductive anode layer by a vacuum gap of less than about 20 μm. ### Claim 3 (depends on 2) The method according to claim 2, wherein the micromachined window is sealed such that each respective isolated vacuum space maintains functionality when the isolated vacuum space of another respective isolated vacuum space fails. ### Claim 4 (depends on 2) The method of claim 2, wherein the solar photovoltaic panel is configured to have a voltage between the transparent conducting anode layer and the photocathode layer of at least 1.2 V under no load under solar illumination. ### Claim 5 (depends on 1) The method according to claim 1, further comprising depositing an antireflective coating on at least one surface of the micromachined window. ### Claim 6 (depends on 1) The method according to claim 1, further comprising coating the micromachined window with a gas diffusion barrier layer on at least one surface. ### Claim 7 (depends on 1) The method according to claim 1, further comprising forming an array of conductive elements configured to form an electrical circuit for conducting current between the photocathode and the anode layer. ### Claim 8 (depends on 1) The method of claim 1, further comprising testing the solar photovoltaic panel under illumination of 1000 W/m2, and demonstrating an output voltage of at least 0.5 V and a current of at least 1000 A/m2. ### Claim 9 (depends on 1) The method of claim 1, wherein the solar photovoltaic panel has an area of 1-3 square feet. ### Claim 10 (depends on 1) The method of claim 1, wherein the micromachined window comprises glass. ### Claim 11 (depends on 1) The method of claim 1, wherein the micromachined window is less than 100 microns thick. ### Claim 12 (depends on 1) The method of claim 1, wherein the reflection layer comprises metallic silver. ### Claim 13 (depends on 1) The method of claim 1, wherein the micron scale roughness of the micropatterned surface of the support is configured to produce specular reflection of the solar irradiation. ### Claim 14 (depends on 1) The method of claim 1, wherein the micromachined window comprises features defining an array of microcell walls which during the sealing forms an electrically insulating separator between the micromachined window and the reflection layer, configured to separate the photocathode layer and the transparent conducting anode layer by less than 20 microns. ### Claim 15 (depends on 1) The method of claim 1, wherein each respective isolated vacuum space of the array comprises a microcell defined by the micromachined window providing an upper microcell boundary and lateral microcells walls sealed to the support providing a lower microcell boundary, each respective microcell being less than about 1 mm across between the lateral microcell walls. ### Claim 16 (depends on 15) The method of claim 15, wherein the lateral microcell walls have a thickness of less than 20 microns. ### Claim 17 (depends on 1) The method of claim 1, wherein the photocathode layer is selected from the family of alkali metal antimonides, where the alkali metal is chosen from one or more of Cs, Na, and K. ### Claim 18 (depends on 1) The method of claim 1, wherein the transparent conducting anode layer comprises either Ag—Cs(O) or doped diamond. ### Claim 19 A method of manufacturing a solar photovoltaic panel, comprising an array of vacuum photodiode microcells, comprising: providing a micromachined window plate configured to admit solar radiation, having a transparent multialkali conducting anode layer comprising at least one of cesium, sodium, potassium, and antimony on an inner surface, partitioned into a regular array of microcells by an array of microcell walls; providing a micropatterned surface of a substrate having micron scale roughness a; depositing a reflective thin film layer on the micropatterned surface of the substrate; depositing a photocathode layer on the reflective thin film layer; and sealing the substrate to the micromachined window plate under vacuum to form a plurality of independent and isolated vacuum photodiode microcells, each respective isolated vacuum photodiode microcell being bounded by the inner surface of the micromachined window plate, the photocathode layer, and the microcell walls, wherein the transparent conducting anode layer and the photocathode layer are separated by less than 20 μm and are responsive to solar irradiation of 1000 W/m2 to generate an open cell voltage of at least 1 V between the transparent conducting anode layer and the photocathode layer, and a transparent conducting anode layer current density of at least 350 A/m2 at a load voltage of 0.5 V. ### Claim 20 (depends on 19) The method of claim 19, wherein the solar photovoltaic panel is further responsive to the solar irradiation of 1000 W/m2 to generate a voltage of at least 0.5 V between the transparent conducting anode layer and the photocathode layer having a current of at least 1000 A/m2.