# US 2018/0321355 A1 · Electronic device with laser marking function and laser marking method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0321355 A1 - Document ID: US20180321355A1 - Status: Published application - Kind: A1 - Application number: 15/859,718 - Filed: 2018-01-01 - Published: 2018-11-08 - Earliest claimed: 2017-05-08 - Assignees: Fu Tai Hua Industry (Shenzhen) Co., Ltd.; Hon Hai Precision Industry Co., Ltd. - Applicants: Fu Tai Hua Industry (Shenzhen) Co., Ltd.; Hon Hai Precision Industry Co., Ltd. - Inventors: LI-HONG LI - Web page: https://patentgrep.com/patent/US20180321355A1 ## CPC - G01S 5/14: Determining absolute distances from a plurality of spaced points of known location - G01S 5/06: Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/12 takes precedence) - G01S 5/16: using electromagnetic waves other than radio waves - G01S 5/22: Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/28 takes precedence) - G01S 5/30: Determining absolute distances from a plurality of spaced points of known location - G03B 21/56: Projection screens - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) ## Abstract A laser marking method for an electronic device with a projector and a projection screen includes first and second microwaves being received by microwave receivers on corners or elsewhere of the projection screen. First and second microwave transmitters in a laser pen transmit the microwaves. Time intervals between transmissions and receptions of the microwaves are acquired. Distances between each of the microwave receivers and each of first and second microwave transmitters are calculated, to establish a three-dimensional rectangular coordinate system. Coordinate value of a point on the screen struck by laser beam (drop point) from the pen is calculated. The method allows for marking the drop point on the screen and also for marking a series of drop points with a line when the laser beam moves across the screen. ## Claims ### Claim 1 An electronic device with a laser marking function comprising: at least one processor; a projection device coupled to the at least one processor and comprising a projection screen, wherein a plurality of microwave receivers is arranged on a plurality of predefined positions of the projection screen; and a storage device coupled to the at least one processor and storing instructions for execution by the at least one processor to cause the at least one processor to: control the plurality of microwave receivers to receive a first microwave transmitted by a first microwave transmitter of a laser pen and a second microwave transmitted by a second microwave transmitter of the laser pen; acquire time intervals between the time when the two microwave transmitters transmit the microwave and the time when each of the plurality of microwave receivers receives the microwave; calculate distances between the plurality of microwave receivers and the first microwave transmitter, and distances between the plurality of microwave receivers and the second microwave transmitter; establish a three-dimensional rectangular coordinate system according to the plurality of microwave receivers and the projection screen; calculate a coordinate value of a drop point formed by a laser beam transmitted from the laser pen on the projection screen, according to the coordinate values of the plurality of microwave receivers, the respective distances between the plurality of microwave receivers and the first and second microwave transmitters; and mark the drop point on the projection screen according to the coordinate value of the drop point. ### Claim 2 (depends on 1) The electronic device according to claim 1, wherein the plurality of predefined positions comprise four vertexes of the projection screen, a microwave receiver being arranged on a vertex of the projection screen. ### Claim 3 (depends on 1) The electronic device according to claim 1, further comprising: a communication device communicating with the laser pen and comprising the plurality of microwave receivers. ### Claim 4 (depends on 1) The electronic device according to claim 1, wherein the projection device is built in the electronic device or is an external device connected with the electronic device. ### Claim 5 (depends on 1) The electronic device according to claim 1, wherein an origin point of the rectangular coordinate system is the position of one microwave receiver, an x-axis of the rectangular coordinate system is the length of the projection screen, a y-axis of the rectangular coordinate system is the width of the projection screen, and a z-axis of the rectangular coordinate system is perpendicular to the projection screen. ### Claim 6 (depends on 1) The electronic device according to claim 1, wherein the at least one processor is further caused to: calculate coordinate values of the two microwave transmitters according to the coordinate values of the plurality of microwave receivers, the distances between the plurality of microwave receivers and the first microwave transmitter, and the distances between the plurality of microwave receivers and the second microwave transmitter; and calculate the coordinate value of the drop point according to the coordinate values of the two microwave transmitters. ### Claim 7 (depends on 1) The electronic device according to claim 1, wherein the at least one processor is further caused to: mark the drop point by displaying a dot on the position of drop point. ### Claim 8 (depends on 1) The electronic device according to claim 1, wherein the at least one processor is further caused to: calculate the coordinate values of a series of drop points when the laser pen is moving; and mark a track of the drop points according to the coordinate values of the drop points. ### Claim 9 (depends on 8) The electronic device according to claim 8, wherein the at least one processor is further caused to: mark the track of the drop points by displaying a faint or a solid line on the position of the track of the drop points. ### Claim 10 A laser marking method comprising: receiving a first microwave transmitted by a first microwave transmitter of a laser pen and a second microwave transmitted by a second microwave transmitter of the laser pen through a plurality of microwave receivers; acquiring time intervals between the time when the two microwave transmitters transmit the microwave and the time when each of the plurality of microwave receivers receives the microwave; calculating distances between the plurality of microwave receivers and the first microwave transmitter, and distances between the plurality of microwave receivers and the second microwave transmitter; establishing a three-dimensional rectangular coordinate system according to the plurality of microwave receivers and a projection screen; calculating a coordinate value of a drop point formed by a laser beam transmitted from the laser pen on the projection screen, according to the coordinate values of the plurality of microwave receivers, the respective distances between the plurality of microwave receivers and the first and second microwave transmitters; and marking the drop point on the projection screen according to the coordinate value of the drop point. ### Claim 11 (depends on 10) The method according to claim 10, wherein there are four microwave receivers arranged on four vertexes of the projection screen. ### Claim 12 (depends on 11) The method according to claim 11, wherein an origin point of the rectangular coordinate system is the position of one microwave receiver, an x-axis of the rectangular coordinate system is the length of the projection screen, a y-axis of the rectangular coordinate system is the width of the projection screen, and a z-axis of the rectangular coordinate system is perpendicular to the projection screen. ### Claim 13 (depends on 10) The method according to claim 10, wherein the step of calculating a coordinate value of a drop point comprises: calculating coordinate values of the two microwave transmitters according to the coordinate values of the plurality of microwave receivers, the distances between the plurality of microwave receivers and the first microwave transmitter, and the distances between the plurality of microwave receivers and the second microwave transmitter; and calculating the coordinate value of the drop point according to the coordinate values of the two microwave transmitters. ### Claim 14 (depends on 10) The method according to claim 10, wherein the step of marking the drop point on the projection screen comprises: marking the drop point by displaying a dot on the position of drop point. ### Claim 15 (depends on 10) The method according to claim 10, further comprising: calculating the coordinate values of a series of drop points when the laser pen is moving; and marking a track of the drop points according to the coordinate values of the drop points. ### Claim 16 (depends on 15) The method according to claim 15, wherein the step of marking a track of the drop points comprises: marking the moving track of the drop points by displaying a faint or a solid line on the position of the track of the drop points.