EXTERNAL LIGHT SOURCE FOR MOBILE DEVICES

Abstract

an external light source is designed as an external flashgun for mobile devices consisting of a xenon flash tube with associated electronic circuitry, whereby the external light source is arranged to operate in at least two modes, in the single flash mode and in the apparent uniform flash mode. The mode of the external light source's operation is set automatically based on the exposure time set on the linked mobile device. One or several external light source are arranged to connect to a mobile device via a radio link, whereby the external light source sends timestamps to the linked mobile device in regular intervals via the radio link. Based on the timestamps, an algorithm in the software running on the mobile device calculates the time delay between the moment photo capture starts on the mobile device and the moment of the flash of light being triggered by the external light source, resulting in the entire frame/subject/scene being uniformly lighted.

Claims

1. An external light source for mobile devices, comprising a housing having a window for light emitted by the external light source, wherein installed inside the housing are at least the following components: a xenon flash with at least one flash tube and associated electronic circuit comprising a capacitor, wherein the circuit is configured to allow for triggering of the xenon flash tube in at least two operation modes: a single flash, and an apparent uniform flash; integrated circuit with a central processing unit and Bluetooth chip, wherein the CPU is configured to perform at least: communication with a mobile device via a radio link, and control of the operation of the external light source; and switch, and a control unit of the switch via which the CPU communicates to trigger the flash tube in accordance with the selected operation mode, wherein the integrated circuit and the switch are arranged to provide a flash in the single flash operation mode of less than 1 millisecond duration via said flash tube, and wherein the integrated circuit and the switch are arranged to provide an apparent uniform flash in the apparent uniform flash operation mode of at least 4 milliseconds duration via said flash tube.

2. An external light source for mobile devices according to claim 1, further comprising an input button arranged at the housing of the external light source, the input button configured to at least one of initiate the capture of a photograph, switch between operation modes or reset the external light source.

3. An external light source for mobile devices according to claim 1, further comprising a first LED for auxiliary lighting of the scene: which is located near the flash tube and serves as a pilot light to assist with the setting of the optical direction of the external light source; which with emitted luminous flux of the first LED assists the linked mobile device to set the parameters for the capture of photographs; and to which an LED controller supplies and manages power for operation, said LED controller being controlled by the CPU.

4. An external source of light according to claim 1, further comprising an inertial measurement unit, built into the electronic circuit located inside the housing of the external source of light, whereby the CPU performs and controls communication with the inertial measurement unit, so that the external light source is able to determine the direction of its optical axis.

5. An external source of light for mobile devices according to claim 1, further comprising an indicator of the unit's status.

6. A system comprising a mobile device and an external light source for the mobile device according to claim 1, wherein the external light source for the mobile device enables connections to the mobile devices via an algorithm embedded in integrated circuitry of the mobile device, which performs at least the following steps: a) searching for nearby wireless devices capable of producing flashes; b) establishing a wireless connection with the external unit found in Step a); c) sending the request for a time value to the external device that the mobile device connected to in Step b); d) as a response to the request in Step c), the external wireless unit sends a time value; and e) calculating the time delay, which equals half of the time elapsed from the request for a timestamp on the external unit to the receipt of the time value; and based on the time delay, the calculation of the exact time on the external unit.

7. An external light source for mobile devices according to claim 1, wherein in the single flash mode, the CPU is configured to calculate how to modulate the voltage on the gate of the switch to achieve the required power of the flash, based on which the voltage on the gate of the switch is adjusted and, consequently, enable the flow of energy from the capacitor into the flash tube for a pre-set time period.

8. (canceled)

9. An external light source for mobile devices according to claim 1, wherein the controller control unit of the switch further calculates the duration and power of the flash so as to enable the control unit to toggle the switch connecting the capacitor to the flash tube at a certain frequency, the result of which is an apparent uniform flash with a duration of at least 25 milliseconds.

10. An external light source for mobile devices according to claim 1, further comprising a third mode of operation, which is the stroboscopic mode of operation, wherein the flash tube emits a sequence of a large number of individual flashes at the desired frequency and power.

11. An external light source according to claim 1, further comprising an electrical power source.

12. The external light source according to claim 1, wherein the apparent uniform flash is a sequence of multiple flashes.

13. A method of using the external light source according to claim 1 in conjunction with a mobile device.

14. A method for lighting a scene using external flash for mobile devices, comprising the following steps: providing wireless connection and time synchronization between an external light source and a mobile device via a radio link; in the case wherein the central processing unit receives the signal to switch an operation mode, switching to the selected mode of operation of the external light source is carried out; in the case wherein the input button located on the housing of the external light source is actuated, the central processing unit of the external light source sends a signal to the operating system of the mobile device via the radio link, to capture a photograph; in the case wherein the operating system of the mobile device receives the signal to capture a photograph, either from the user interface of the mobile device itself or from the external light source: the capture of a photograph is scheduled within the operating system of the mobile device; and a signal on the time to trigger the flash is sent to the external light source.

15. The method according to claim 14, wherein the central processing unit of the external light source, after having established the connection and performed time synchronization, waits to receive the signal to capture a photograph: either from the circuit detecting the actuation of the input button located on the housing of the external light source; or from the mobile device via the radio link, whereby the signal to capture a photograph also comprises the information relating to the time to trigger the flash.

16. An external light source for mobile devices according to claim 1, wherein the switch comprises an IGBT switch connecting the capacitor and the flash tube.

17. An external light source for mobile devices according to claim 3, wherein emitted luminous flux assists the linked mobile device to set the parameters for the capture of photographs to focus on objects in a frame even in complete darkness.

18. An external light source for mobile devices according to claim 5, wherein the indicator comprises a multi-colored lamp.

19. An external light source for mobile devices according to claim 18, wherein the multi-colored lamp comprises a RGBW LED.

20. An external light source for mobile devices according to claim 5, wherein the indicator is configured to communicate to the user one or more states of the external source light, the one or more states comprising at least one of: the external source of light is on; low battery status; the external source of light is overheating; the battery is being charged correctly; or the battery is fully charged.

21. An external light source for mobile devices according to claim 11, wherein the electrical power source comprises at least one of an integrated battery or a charging port.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The present invention of a light source for mobile devices will be described below with the implementation examples and figures displaying:

[0074] FIG. 1 shows an isometric projection and view from below according to an implementation example

[0075] FIG. 2 shows a block diagram according to the implementation example

[0076] FIG. 3 is a diagram of a connection and time synchronization process according to the implementation example

[0077] FIG. 4 is a diagram of the subject/scene lighting process according to the implementation example.

DETAILED DESCRIPTION

[0078] The general exterior design of the external lighting source according to the first implementation example is shown in FIG. 1. The external lighting source comprises a housing 1 with a window 2 for emitted light, The external lighting source may further comprise a status indicator 3. The external lighting source may further comprise a multifunction input button 4. The external lighting source may further comprise a charging port 5. The external lighting source may further comprise a mounting receptacle 6. The mounting receptacle 6 is in the illustrated example a hole with threads. In the illustrated example, the status indicator 3, the multifunction input button 4, the charging port 5 and the mounting receptacle 6 are arranged at the exterior of the housing 1.

[0079] The housing 1 also features the following elements either comprised inside or located on its exterior: [0080] a linear flash tube, which emits light through the appropriately shaped housing window 2. The flash tube operates in at least two modes: [0081] an single flash mode. The power settings of the single flash mode may range from the maximum flash power to 1/512 of maximum possible flash power, [0082] an apparent uniform flash mode. The duration of the flash may be up to 40 ms, and preferably between 4 ms and 25 ms. [0083] optional stroboscopic operation mode.th preferably frequencies up to 100 Hz; [0084] a source of electrical power, such as an integrated battery; [0085] an electronic circuit to deliver power to the flash tube; [0086] an IGBT switch controller and the IGBT switch; [0087] integrated circuit with a central processing unit (CPU) and a built-in Bluetooth chip; [0088] an inertial measurement unit (IMU); [0089] a charging port, preferably a USB-C female connector; [0090] a multi-function input button to power the device on and off, to trigger the capturing of a photo, to switch between operation modes or to reset the device; [0091] a RGBW LED to model light, as auxiliary light or as a source of lighting for video recording.

[0092] FIG. 2 displays the block diagram according to the implementation example, which comprises a mobile device 7; an electronic circuit 8 of an external light source comprising an integrated circuit 9, wherein the integrated circuit 9 comprises a Bluetooth chip 10 and a central processing unit 11; an inertial measurement unit (IMU) 12 arranged to detect spatial orientation; an input button 13; and electronic circuit 14 for supplying power to a flash tube 17, which includes at least: [0093] a capacitor 15, preferably with a capacitance between 500 and 1500 microfarads, [0094] a source of electrical power, such as an integrated battery, [0095] a transformer to transform voltage of the integrated battery to high voltage; preferably in the range between 300 and 400 volts, [0096] a controller for the charging of the capacitor 15, [0097] an IGBT switch controller and an IGBT switch 16, [0098] a xenon flash tube 17.

[0099] FIG. 3 displays the diagram of a connection and time synchronization process according to the implementation example. The mobile device first searches for the external light source in Step 18 and connects to it in Step 19. The search and connection between the mobile device and the external light source makes use of the Bluetooth chip and of the corresponding components in the mobile device to enable a Bluetooth connection. Then the mobile device sends its request for the time value to the connected device in Step 20. The external unit then replies to the request and sends back its time value in Step 21. The mobile device receives the time value in Step 22. Based on the time elapsed between the request for the time value having been sent to the external unit and the received time value, the mobile device determines in Step 23 the exact current time on the external unit and the time delay that has to be taken into account in communication with the external unit. Steps from 20 to and including 23 are intended for time synchronization between the external unit and the mobile device.

[0100] FIG. 4 displays the process of lighting a subject or a scene according to the implementation example. Step 24 consists of the time synchronization between a mobile device and the external light source as described in Steps 20 through 23. The operating system receives a signal to capture a photo: [0101] via a Bluetooth link from the central processing unit of the external light source after the input button on its housing has been actuated; or [0102] from the user interface of the mobile device.

[0103] The mobile device's operating system upon receiving a signal to capture a photograph in Step 25, schedules the capture of the photo for a point in time in Step 26, and substantially simultaneously in Step 27 send to the external light source the signal detailing the information on the flash triggering time and on the power of the flash. If the external light source is set to the apparent uniform flash mode, the signal sent to it also comprises information relating to the duration of the flash. If the external light source is set to the stroboscopic operation mode, the signal sent to it also comprises information relating to the frequency of the flashes. If the mobile device sends to the external light source a signal to switch operation modes in Step 28, then the external light source will switch to the selected mode in Step 29. At the moment of the photo capture initiation, the process of triggering the flash is as follows: the CPU of the external light source sends the information on the modulation parameters to the IGBT switch controller, which in turn starts modulating the voltage at the IGBT gate. Consequently, the charged capacitor will connect once or several times with the flash tube, which will emit a single flash or multiple flashes, depending on the operation mode set in Step 28.