Electronic flash, electronic camera and light emitting head

• US 8,634,021 B2
• Filed: 07/07/2006
• Issued: 01/21/2014
• Est. Priority Date: 07/25/2000
• Status: Expired due to Term

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Kawakami, Chikuni
• Primary Examiner(s): Velez, Roberto
• Assistant Examiner(s): FOSSELMAN, JOEL W
• Application Number:
  US11/482,171
• Publication Number:
  US 20060250519A1
• Time in Patent Office: 2,755 Days
• Field of Search: 348/371, 348/223.1, 348/224.1, 396155-206
• US Class Current: 348/371
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/0521 movable housing, e.g. bounce-light
• CPC Class Codes: G03B 2215/0535 Built-in diffusor
• CPC Class Codes: G03B 2215/0567 Solid-state light source, e.g. LED, laser
• CPC Class Codes: G03B 2215/0592 installed in front of light emitter
• CPC Class Codes: H04N 23/10 for generating image signals from different wavelengths
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control
• CPC Class Codes: H04N 25/713 Transfer or readout registers; Split readout registers or multiple readout registers
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 5/77 between a recording apparatus and a television camera
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• CPC Class Codes: H05B 45/37 Converter circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

R, G and B LEDs are used as a light source of an electronic flash. Electric energy is supplied to a capacitor to the LEDs. A system controller controls light emitting amounts of the LEDs so that a color temperature of the electronic flash light becomes a color temperature that has been manually set with a color temperature setting switch or a color temperature of a light source determined by color temperature sensors.

Claims

1. An electronic flash of a camera, comprising:

a plurality each of R, G, and B light emitting diodes that are used as an electronic flash light source;

a power supply device;

a color temperature sensor which senses color temperature of a subject field; and

a light emission control device that supplies electric energy separately to each one of the plurality of R, G, and B light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B that are emitted from the plurality of R, G, and B light emitting diodes and a total light emission amount of R, G, and B, wherein

the light emission control device determines a desired light emission color so as to adapt to the color temperature of the subject field sensed by said color temperature sensor and determines the ratios between light emission amounts of R, G, and B so as to adapt to the determined desired light emission color, and performs control to turn on and off individual ones of the plurality of R, G, and B light emitting diodes, respectively, with duty ratios corresponding to the ratios between light emission amounts of R, G, and B such that a desired light emission color is emitted by the electronic flash source,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color; and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

2. The electronic flash of a camera as defined in claim 1, wherein the light emission control device comprises:

a light adjusting sensor that determines an amount of reflected light from a subject of light emitted from the light emitting diodes; and

a light emission stopping control device that stops light emission of the light emitting diodes when the amount of received light determined by the light adjusting sensor reaches a predetermined reference value.

3. The electronic flash of a camera as defined in claim 1, wherein the duty ratios are not the same.

18. The electronic flash of a camera according to any one of claims 1 to 5 and 12 to 17, further comprising a diffusion plate for diffusing light emitted from the light emitting diodes, which is provided in front of the light emitting diodes.

4. An electronic flash of a camera, comprising:

a plurality each of R, G, and B light emitting diodes that are used as an electronic flash light source;

a power supply device;

a color temperature sensor which senses color temperature of a subject field;

a recording device that records the color temperature of the subject field sensed by said color temperature sensor;

a designating device that designates reading of the color temperature that is recorded in the recording device; and

a light emission control device that supplies electric energy separately to each one of the plurality of R, G, and B light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B that are emitted from the plurality of R, G, and B light emitting diodes and a total light emission amount of R, G, and B, wherein

when a desired color temperature is read from the recording device by the designating device, the light emission control device controls the ratios between light emission amounts of R, G, and B and performs control to turn on and off individual ones of the plurality of R, G, and B light emitting diodes, respectively, with duty ratios corresponding to the ratios between light emission amounts of R, G, and B so as to generate the color temperature that is read,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

5. The electronic flash of a camera as defined in claim 4, wherein the light emission control device comprises:

a light adjusting sensor that determines one of an amount of reflected light from a subject of light emitted from one of the R, G, and B light emitting diodes for which a light emitting amount is smallest among the R, G, and B light emitting diodes and an amount of reflected light from the subject of light emitted from the R, G, and B light emitting diodes;

a first light emission stopping control device that stops light emission of the one of the R, G, and B light emitting diodes for which a light emitting amount is smallest when the one of the amounts of received light determined by the light adjusting sensor reaches a predetermined reference value according to the ratios between the light emitting amounts from the R, G, and B light emitting diodes;

a measuring device that measures a light emitting time of the light emitting diode that is subjected to light emission control by the first light emission stopping control device;

a calculating device that calculates light emitting times of others of the R, G, and B light emitting diodes according to the light emitting time measured by the measuring device and the ratios between the light emitting amounts from the R, G, and B light emitting diodes; and

a second light emission stopping control device that stops light emission of the others of the R, G, and B light emitting diodes according to the light emitting times calculated by the calculating device.

6. The electronic flash of a camera as defined in claim 4, wherein the duty ratios are not the same.

7. An electronic camera that stores color image signals of a subject image on recording medium captured with a taking lens and an imaging device, the electronic camera comprising:

a plurality each of R, G, and B light emitting diodes that are used as an electronic flash light source;

a power supply device;

a determining device that determines a color temperature of the color image signals based on color image signals of a subject image captured with the imaging device before a shooting; and

a light emission control device that supplies electric energy separately to each one of the plurality of R, G, and B light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B that are emitted from the plurality of R, G, and B light emitting diodes and a total light emission amount of R, G, and B, wherein the light emission control device determines a desired light emission color so as to adapt to the color temperature determined by said determining device and determines the ratios between light emission amounts of R, G, and B so as to adapt to the determined desired light emission color, and controls the ratios between light emission amounts of R, G, and B by performing control to turn on and off individual ones of the plurality of R, G, and B light emitting diodes, respectively, with duty ratios corresponding to the ratios between light emission amounts of R, G, and B such that a desired light emission color is emitted by the electronic flash source in correspondence to the ratios between R, G, and B that are determined by the determining device,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

8. The electronic camera as defined in claim 7, wherein the light emission control device comprises:

a light adjusting sensor that determines one of an amount of reflected light from a subject of light emitted from one of the R, G, and B light emitting diodes for which a light emitting amount is smallest among the R, G, and B light emitting diodes and an amount of reflected light from the subject of light emitted from the R, G, and B light emitting diodes;

a first light emission stopping control device that stops light emission of the one of the R, G, and B light emitting diodes for which a light emitting amount is smallest when the one of the amounts determined by the light adjusting sensor reaches a predetermined reference value according to the ratios between the light emitting amounts from the R, G, and B light emitting diodes;

a measuring device that measures a light emitting time of the light emitting diode that is subjected to light emission control by the first light emission stopping control device;

a calculating device that calculates light emitting times of others of the R, G, and B light emitting diodes according to the light emitting time measured by the measuring device and the ratios between the light emitting amounts from the R, G, and B light emitting diodes; and

a second light emission stopping control device that stops light emission of the others of the R, G, and B light emitting diodes according to the light emitting times calculated by the calculating device.

9. The electronic camera according to claim 7 or 8, further comprising a diffusion plate for diffusing light emitted from the light emitting diodes, which is provided in front of the light emitting diodes.

10. The electronic camera according to claim 7, wherein auto white balance correction is performed to the captured image obtained with said imaging device.

11. The electronic camera as defined in claim 7, wherein the duty ratios are not the same.

14. The electronic flash of a camera as defined in claim 7, wherein the light emission control device comprises:

a light adjusting sensor that determines an amount of reflected light tom a subject of light emitted from the light emitting diodes; and

a light emission stopping control device that stops light emission of the light emitting diodes when the amount of received light determined by the light adjusting sensor reaches a predetermined reference value.

12. An electronic flash of a camera, comprising:

a plurality of light emitting diodes that are used as an electronic flash light source;

a power supply device;

a color temperature sensor which senses color temperature of a subject field; and

a light emission control device that supplies electric energy to the light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B and total light emission amounts of R, G, and B that are emitted from the light emitting diodes;

wherein the light emission control device includes;

a switching device for supplying electric energy from the power supply device to the light emitting diodes;

an electric current determining device that determines an electric current flowing to the light emitting diodes; and

a pulse width controlling device determines a desired light emission color so as to adapt to the color temperature of the subject field sensed by said color temperature sensor and determines the ratios between light emission amounts of R, G, and B so as to adapt to the determined desired light emission color, and performs control to turn the switching device on and off by use of a pulse signal that is controlled by a duty ratio corresponding to the determined ratio and so that an electric current that is determined by the electric current determining device becomes a desired constant current, wherein

the pulse width controlling device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the pulse width controlling device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

13. The electronic flash of a camera as defined in claim 12, wherein

the light emission control device comprises a coil that is connected in series with the light emitting diodes, and a diode in which a cathode side is connected with the coil and an anode side is grounded to a ground, and wherein

the light emission control device flows electric current from the power supply device to the light emitting diodes via the coil while the switching device is turned on, and flows electric current to the light emitting diodes via the diode and the coil by an induced electromotive force of the coil when the switching device is turned off.

15. The electronic flash of a camera as defined in claim 12, wherein,

the light emitting diodes comprise R, G and B light emitting diodes;

the switching device and the electric current determining device are provided for the R, G and B light emitting diodes, respectively; and

the pulse width controlling device performs control to turn the respective switching devices of the R, G and B light emitting diodes on and off by use of pulse signals that are controlled by respective duty ratios so that a ratio of light emission levels of R, G and B that are emitted from the R, G and B light emitting diodes becomes a desired ratio.

16. The electronic flash of a camera as defined in claim 12, wherein the power supply device comprises:

a battery;

a boosting device that boosts a power supply voltage from the battery; and

a capacitor with a large capacity that is charged by a voltage that is boosted by the boosting device.

17. The electronic flash of a camera as defined in claim 12, further comprising:

a temperature sensor that determines a temperature of the light emitting diode;

wherein, based on a temperature determined by the temperature sensor, the light emission control device supplies electric energy to the light emitting diodes so as to obtain a desired light emission amount regardless of the temperature.

19. The electronic flash of a camera as defined in claim 12, wherein the duty ratios are not the same.

20. An electronic flash of a camera, comprising:

an electronic flash light source including R, G, and B light emitting diodes;

a power supplying device which supplies power; and

a switching device which supplies electric energy from the power supplying device to the R, G, and B light emitting diodes; and

a light emission control device which controls ratios between light emission amount of R, G, and B and total light emission amounts of R, G, and B that are emitted from the light emitting diodes,

wherein the light emission control device includes;

an inductor which is series-connected to the light emitting diode; and

a diode, a cathode side of which is connected to the inductor and a anode side of which is connected to ground, and

wherein the light emission control device is operable to flow electric current from the power supplying device to the light emitting diode via the inductor while the switching device is ON, and is operable to flow electric current to the light emitting diode via the diode and the inductor by induction electromotive force of the inductor while the switching device is OFF,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

21. The electronic flash of a camera as defined in claim 20, wherein the duty ratios are not the same.

22. An electronic camera that stores color image signals of a subject image captured with a taking lens and an imaging device on a recording medium, the electronic camera comprising:

a plurality each of R, G, and B light emitting diodes that are used as an electronic flash light source;

a power supply device;

a color temperature sensor which senses color temperature of a subject field; and

a light emission control device that supplies electric energy separately to each one of the plurality of R, G, and B light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B that are emitted from the plurality of R, G, and B light emitting diodes and a total light emission amount of R, G, and B, wherein

the light emission control device determines a desired light emission color so as to adapt to the color temperature of the subject field sensed by said color temperature sensor and determines the ratios between light emission amounts of R, G, and B so as to adapt to the determined desired light emission color, and performs control to turn on and off individual ones of the plurality of R, G, and B light emitting diodes, respectively, with duty ratios corresponding to the ratios between light emission amounts of R, G, and B such that a desired light emission color is emitted by the electronic flash source,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

23. An electronic camera that stores color image signals of a subject image captured with a taking lens and an imaging device on a recording medium, the electronic camera comprising:

a plurality each of R, G, and B light emitting diodes that are used as an electronic flash light source;

a power supply device;

a color temperature sensor which senses color temperature of a subject field;

a recording device that records the color temperature of the subject field sensed by said color temperature sensor;

a designating device that designates reading of the color temperature that is recorded in the recording device; and

a light emission control device that supplies electric energy separately to each one of the plurality of R, G, and B light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B that are emitted from the plurality of R, G, and B light emitting diodes and a total light emission amount of R, G, and B, wherein

when a desired color temperature is read from the recording device by the designating device, the light emission control device controls the ratios between light emission amounts of R, G, and B and performs control to turn on and off individual ones of the plurality of R, G, and B light emitting diodes, respectively, with duty ratios corresponding to the ratios between light emission amounts of R, G, and B so as to generate the color temperature that is read,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

24. An electronic camera that stores color image signals of a subject image captured with a taking lens and an imaging device on a recording medium, the electronic camera comprising:

a plurality of light emitting diodes that are used as an electronic flash light source;

a power supply device;

a color temperature sensor which senses color temperature of a subject field; and

a light emission control device that supplies electric energy to the light emitting diodes from the power supply device, and controls ratios between light emission amounts of R, G, and B and total light emission amounts of R, G, and B that are emitted from the light emitting diodes;

wherein the light emission control device includes;

a switching device for supplying electric energy from the power supply device to the light emitting diodes;

an electric current determining device that determines an electric current flowing to the light emitting diodes; and

a pulse width controlling device determines a desired light emission color so as to adapt to the color temperature of the subject field sensed by said color temperature sensor and determines the ratios between light emission amounts of R, G, and B so as to adapt to the determined desired light emission color, and performs control to turn the switching device on and off by use of a pulse signal that is controlled by a duty ratio corresponding to the determined ratio and so that an electric current that is determined by the electric current determining device becomes a desired constant current, wherein

the pulse width controlling device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the pulse width controlling device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to the desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.

25. An electronic camera that stores color image signals of a subject image captured with a taking lens and an imaging device on a recording medium, the electronic camera comprising:

an electronic flash light source including R, G, and B light emitting diodes;

a power supplying device which supplies power; and

a switching device which supplies electric energy from the power supplying device to the R, G, and B light emitting diodes; and

a light emission control device which controls ratios between light emission amount of R, G, and B and total light emission amounts of R, G, and B that are emitted from the light emitting diodes,

wherein the light emission control device includes;

an inductor which is series-connected to the light emitting diode; and

a diode, a cathode side of which is connected to the inductor and a anode side of which is connected to ground, and

wherein the light emission control device is operable to flow electric current from the power supplying device to the light emitting diode via the inductor while the switching device is ON, and is operable to flow electric current to the light emitting diode via the diode and the inductor by induction electromotive force of the inductor while the switching device is OFF,

the light emission control device makes each of a start and end of a light emission time of the R, G, and B light emitting diodes to be substantially the same, wherein light emission of each of the R, G, and B light emitting diodes ends when the respective light emission amounts of R, G, and B reach desired amounts according to the desired light emission color, and

the light emission control device controls pulse width and turning on/off of individual ones of the plurality of R, G, and B light emitting diodes, respectively, between the start and the end of the light emission time in order to obtain desired duty ratios corresponding to desired ratios between light emission amounts of R, G, and B and with the same number of pulses for at least two colors of R, G, and B, each having a plurality of pulses.