JP2006139297A - Flash device, camera device equipped with the same and color temperature control method for flash device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flash device obtaining electronic flash light of requested color temperature irrespective of variance in luminous intensity of a light emitting element in use, and also to provide a camera device equipped with the flash device and a color temperature control method for the flash device. <P>SOLUTION: LEDs of three colors R, G and B are driven with pulses to emit light, so that white electronic flash light is obtained. The ratio of total light emission time is determined according to the light emission luminous intensity of the individual LEDs in use and stored in a memory on factory shipment. When emitting the light, light emission frequencies n<SB>R</SB>, n<SB>G</SB>and n<SB>B</SB>by which the determined ratio is obtained as the ratio of total light emission time Tr, Tg and Tb (integration of parts where currents flow actually) for every light emission color in an exposure time are computed, and the LEDs are driven by every color with pulses at the computed light emission frequencies n<SB>R</SB>, n<SB>G</SB>and n<SB>B</SB>. The ratio of the total light emission time Tr, Tg and Tb is controlled to the ratio set on the factory shipment, and the electronic flash light becomes the white light of a prescribed requested color temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flash device having light emitting elements of a plurality of colors, a camera device including the same, and a color temperature control method for the flash device.

  Conventionally, in a digital camera that captures a subject using a silver salt camera or a CCD-type or MOS-type solid-state image pickup device and records the image as image data on a recording medium such as a flash memory, for example, the amount of light at the time of shooting is insufficient. A built-in or external strobe is used to compensate. Generally, a xenon tube is used as a light emitting element in a strobe, and the xenon tube emits light when electric power previously charged in a main capacitor is supplied in response to a trigger signal. On the other hand, charging to the main capacitor is performed immediately after the power-on operation or after the strobe is turned on, but a waiting time of several seconds is required for the charging. Therefore, a strobe using a xenon tube cannot shoot within the waiting time. In addition, even if the main capacitor is small, the diameter is about 10 mm and the length is about 25 to 40 mm.

  For this reason, a light emitting diode (hereinafter referred to as an LED) is used as a light emitting element, so that a main capacitor is not required, and by using LEDs having different emission colors, strobe light of various colors is emitted. It is considered to be possible. By the way, in general, there is a variation in luminous intensity between solids in LEDs, each of which is ranked according to luminous intensity, and in use, an LED with a rank within an allowable range, or a predetermined rank with which a necessary luminous intensity can be obtained. LEDs are selectively used.

  However, in a flash device using LEDs as light emitting elements, for example, when white strobe light is realized using LEDs of three colors of emission colors R, G, and B, LEDs of a predetermined rank are selectively used as described above. Even if it is used, there is a problem in that the color temperature of the mixed light of each LED varies from device to device due to the slight variation in luminous intensity existing in each LED.

  The present invention has been made in view of such a conventional problem, and a flash device capable of obtaining strobe light of a required color temperature regardless of variations in luminous intensity among light emitting elements to be used, and a camera equipped with the flash device An object of the present invention is to provide a color temperature control method for an apparatus and a flash device.

  In order to solve the above-mentioned problem, the invention of claim 1 is a flash device, which emits light of a plurality of colors having different emission colors, and emits the light of the plurality of colors according to demand, and emits light. And a control means for controlling the ratio of the total emission time for each emission color in the operation period, that is, the time during which the light emission operation is continuously performed, to a specific ratio determined according to each light emitting element. .

  In such a configuration, during the light emitting operation period, the ratio of the total light emitting time of the light emitting elements for each light emitting color is controlled to a specific ratio determined according to each light emitting element. Therefore, by predetermining the ratio of the total light emission time of the light emitting elements for each light emitting color in accordance with the predetermined color temperature required for the apparatus, regardless of the variation in luminous intensity in each of the light emitting elements of a plurality of colors. A predetermined color temperature required for the apparatus can be reliably obtained in the strobe light which is a mixed light of all the light emitting elements.

  According to a second aspect of the present invention, there is provided driving means for causing the light emitting elements of the plurality of colors to emit light by pulse driving, and the control means controls the number of times of pulse driving by the driving means for each emission color. did.

  In such a configuration, the number of pulse driving times of the light emitting elements of the plurality of colors is controlled for each light emission color, whereby the ratio of the total light emission time for each light emission color in the light emitting elements of the plurality of colors is controlled to a predetermined ratio.

  According to a third aspect of the present invention, the control means performs pulse driving of light emitting elements having a light emission color other than the light emission color within the drive time of the light emitting element having the largest ratio of the total light emission time. The timing was averaged for each emission color.

  In such a configuration, all the light emission operation intervals of the light emitting elements of a plurality of colors within the light emission operation period are averaged, and the change in the color temperature of the strobe light during the light emission operation period becomes uniform.

  According to a fourth aspect of the present invention, there is provided driving means for driving the plurality of light emitting elements to emit light, and the control means determines the driving time of the light emitting elements of the plurality of colors driven by the driving means. It was supposed to be controlled every time.

  In such a configuration, the light emitting elements of a plurality of colors are continuously driven, and the driving time for each light emitting color is controlled to determine the ratio of the total light emitting time for each light emitting color in the light emitting elements of the plurality of colors. Controlled by rate.

  According to a fifth aspect of the present invention, the control means continuously drives the light emitting element having a light emission color having the largest ratio of the total light emission time to the drive means, and the light emission within the continuous drive time. A light emitting element having a light emission color other than a color is intermittently driven in a time division manner for each light emission color.

  In such a configuration, all the light emission operation intervals of the light emitting elements of a plurality of colors within the light emission operation period are averaged, and the change in the color temperature of the strobe light during the light emission operation period becomes uniform.

  In the invention of claim 6, the light emitting element is a light emitting diode.

  According to a seventh aspect of the invention, there is provided a camera device comprising the flash device according to any one of the first to sixth aspects.

  The invention according to claim 8 is a method for controlling the color temperature of light emitted from a flash device having a plurality of light emitting elements having different emission colors, wherein the ratio of the total emission time for each emission color is individually determined. When the light emitting elements of the plurality of colors are caused to emit light according to demand, the ratio of the total light emission time for each light emission color during the light emission operation period of the flash device is controlled to the predetermined ratio. I tried to do it.

  According to this method, it is possible to reliably obtain a predetermined color temperature required for the apparatus in the strobe light that is a mixed light of the light of all the light emitting elements regardless of the variation in luminous intensity in each of the light emitting elements of a plurality of colors. Can do.

  As described above, in the first and eighth aspects of the invention, the ratio of the total light emission time of the light emitting elements for each light emission color is determined in advance corresponding to the predetermined color temperature required for the apparatus. Thus, it is possible to reliably obtain a predetermined color temperature required for the apparatus in the strobe light that is a mixed light of the light of all the light emitting elements regardless of the variation in luminous intensity in each of the light emitting elements of a plurality of colors. .

  In the invention of claim 2, the ratio of the total light emission time for each light emission color in the light emitting elements of the plurality of colors is determined by controlling the number of times of pulse driving of the light emitting elements of the plurality of colors for each light emission color. To be controlled. Therefore, it is possible to reliably obtain a predetermined color temperature required for the apparatus for strobe light, which is a mixed light of all the light emitting elements, regardless of variations in luminous intensity in each of the light emitting elements of a plurality of colors. .

  Furthermore, in the invention of claim 3, all the light emitting operation intervals of the light emitting elements of a plurality of colors within the light emitting operation period are averaged so that the change in the color temperature of the strobe light becomes uniform within the light emitting operation period. did. Therefore, it is possible to shoot with a uniform color even when shooting a subject with intense movement.

  In the invention of claim 4, the light emitting elements of a plurality of colors are continuously driven, and the driving time for each light emitting color is controlled at that time, so that the total light emitting time for each light emitting color in the light emitting elements of the plurality of colors is The ratio was controlled to a fixed ratio. Therefore, it is possible to reliably obtain a predetermined color temperature required for the apparatus for strobe light, which is a mixed light of all the light emitting elements, regardless of variations in luminous intensity in each of the light emitting elements of a plurality of colors. .

  Furthermore, in the invention of claim 5, all the light emitting operation intervals of the light emitting elements of a plurality of colors within the light emitting operation period are averaged so that the change in the color temperature of the strobe light becomes uniform within the light emitting operation period. did. Therefore, it is possible to shoot with a uniform color even when shooting a subject with intense movement.

  In the invention of claim 6, the above effect can be obtained in a configuration in which the light emitting element is a light emitting diode.

  According to the seventh aspect of the present invention, in a camera device including a flash device having light emitting elements of a plurality of colors, a required predetermined color temperature can be reliably obtained for the strobe light emitted from the flash device. Therefore, it is possible to shoot with a good color balance even during flash photography.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing an electrical configuration of a digital camera 2 (camera apparatus of the present invention) incorporating a strobe 1 which is a flash apparatus of the present invention. The digital camera 2 includes a CCD 4 that captures a subject image formed through the imaging lens 3, a TG (Timing Generator) 5 and a V driver 6 for driving the CCD 4, and an imaging signal output from the CCD 4. The unit circuit 7 includes a CDS to be held, a gain adjustment amplifier (AGC) that amplifies the image pickup signal, and an A / D converter (AD) that converts the amplified image pickup signal into a digital signal.

  The CCD 4 functions as an electronic shutter by changing the charge accumulation time by a TG (Timing Generator) 5 and a V driver 6 in accordance with a shutter pulse sent from the MPU 8. The MPU 8 has various signal processing and image processing functions. The MPU 8 generates a video signal from an imaging signal converted into a digital signal through the unit circuit 7, and a liquid crystal monitor using the subject image captured by the CCD 4 as a through image. 9 is displayed. Further, at the time of shooting, the image pickup signal is compressed to generate an image file of a predetermined format and stored in the flash memory 10, while at the time of reproduction, the compressed image file is expanded and displayed on the liquid crystal monitor 9.

  The MPU 8 includes a power supply circuit 11 including a power source such as a battery, an operation key unit 12 including various switches such as a shutter key, a DRAM 13 serving as a working memory, and various types of data necessary for control and data processing by the MPU 8. An EEPROM 14 in which an operation program is recorded and a light emission control block 15 are connected. The light emission control block 15 has a plurality of light emitting elements having different emission colors, that is, a red LED (LED-R) 16 and a green LED (LED -G) 17 and blue LED (LED-B) 18 are connected.

  The light emission control block 15 is a driving means of the present invention, which supplies a pulse current of a value determined to each LED 16, 17, 18 based on the control of the MPU 8 in the flash photography mode, and drives each LED 16, 17, 18 by pulse driving. Make it emit light. The EEPROM 14 stores a program for causing the MPU 8 to control the operation of each unit described above and various setting data. In the present embodiment, the setting data stores light emission control data used when controlling the light emission control block 15 in the flash photography mode. This light emission control data is specific data determined in advance according to the individual LEDs 16, 17, 18 used, more specifically according to the light emission intensity of the individual LEDs 16, 17, 18, ie, It is data specific to each device, and is a data indicating the ratio of the total light emission time for each light emission color when each LED 16, 17, 18 is caused to emit light. Further, the light emission control data in the present embodiment is ratio data such as “Rt: Gt: Bt”, and the value thereof is a predetermined value for strobe light, which is a mixed light of the LEDs 16, 17, 18 at the time of factory shipment. It is a value when it is adjusted to become white light with a color temperature of.

  In this embodiment, the MPU 8 functions as the control means of the present invention by controlling the operation of the light emission control block 15 based on the light emission control data. That is, in the present embodiment, the strobe 1 is constituted by the MPU 8, the EEPROM 14, the light emission control block 15, and the LEDs 16, 17, and 18.

Next, in this embodiment, the control contents when the MPU 8 controls the operation of the strobe 1 according to the trigger signal sent from the operation key unit 12 when the shutter key is pressed will be described with reference to the flowchart of FIG. When a trigger signal is sent from the operation key unit 12 (YES in step SA1), the MPU 8 reads the ratio data (Rt, Gt, Bt) described above from the EEPROM 14 (step SA2), and based on this, the red color within the exposure time of the CCD 4 is read. The number of times of pulse driving (number of times of light emission) n _R , n _G , and n _B of each of the LED 16, the green LED 17, and the blue LED 18 is individually calculated (step SA3). More specifically, the pulse driving times n _G and n _B of the green LED 17 and the blue LED 18 are calculated based on the pulse driving number n _R within the exposure time of the red LED 16 having the largest ratio of the total light emission time. Thereafter, as shown in FIG. 3, the light emission control block 15 drives the LEDs 16, 17, and 18 all at once, and drives the calculated light emission times n _R , n _G , and n _{B for} each color ( Step SA4).

  As a result, the ratio of the total light emission times Tr, Tg, Tb (actually the integration of the portion through which the current flows) of each of the LEDs 16, 17, 18 within the exposure time of the CCD 4 is set at the time of factory shipment ( Rt: Gt: Bt), and a predetermined color temperature required for the strobe light is secured.

  Therefore, according to the present embodiment, as described above, the ratio data (Rt: Gt: Bt) obtained when the strobe light is adjusted in advance to become white light having a predetermined color temperature is stored in the EEPROM 14. Therefore, white light having a required color temperature can be secured in the strobe light, which is a mixed light of all the light emitting diodes, regardless of variations in the luminous intensity of each of the LEDs 16, 17, and 18. . In addition, since the MPU 8 is configured to control the color temperature of the strobe light by controlling the number of times the LEDs 16, 17, and 18 are driven by the light emission control block 15, new driving is performed in addition to the existing light emission control block 15. There is no need to add a circuit.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, in a digital camera having the same configuration as that of the first embodiment, the EEPROM 14 causes the MPU 8 to perform the flash control shown in the flowchart of FIG. 4 different from the first embodiment. A program is stored.

Also in the present embodiment, when a trigger signal is sent from the operation key unit 12 (YES in step SB1), the MPU 8 reads the ratio data (Rt, Gt, Bt) described above from the EEPROM 14 (step SB2), and based on that, The red LED 16, green LED 17, and blue LED 18 emit light numbers (pulse drive times) n _R , n _G , and n _B within the exposure time T of the CCD 4 are individually calculated (step SB3). Further, the MPU 8 calculates pulse drive intervals (drive periods) i _R , i _G , i _B within the exposure time T of the CCD 4 corresponding to the calculated light emission times n _R , n _G , n _B (step SB4). Thereafter, as shown in FIG. 5, the light emission control block 15 calculates the LEDs 16, 17, and 18 within the exposure time T of the CCD 4 with the calculated pulse drive intervals i _R , i _G , and i _B , respectively. The light is emitted periodically n _R , n _G , and n _B (step SB5).

  Thus, within the exposure time T of the CCD 4, the ratio of the individual total light emission time of each of the LEDs 16, 17, 18 (actually the integrated value of the portion where the current flows) is set at the time of factory shipment (Rt: Gt: Bt), the required predetermined color temperature is ensured for the strobe light. Therefore, the same effect as the first embodiment can be obtained.

  Further, within the exposure time T of the CCD 4, the light emission timings of the LEDs 16, 17, 18 are averaged, so that the change in the color temperature of the strobe light within the light emission operation period (exposure time) of the strobe 1 is uniform. Become. Therefore, even when shooting a subject with intense movement, shooting with a uniform color is possible, and good shooting results can be obtained even with strobe shooting when the subject moves intensely.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the present embodiment, in the digital camera having the configuration shown in FIG. 1, the light emission control block 15 supplies a drive current having a value determined to each of the LEDs 16, 17, and 18 based on the control of the MPU 8 in the flash photography mode. The LEDs 16, 17 and 18 emit light, and the EEPROM 14 stores a program for causing the MPU 8 to perform the strobe control shown in FIG. 6.

  Also in the present embodiment, when a trigger signal is sent from the operation key unit 12 (YES in step SC1), the MPU 8 reads the ratio data (Rt, Gt, Bt) described above from the EEPROM 14 (step SC2). The drive times (light emission times) Tr, Tg, Tb of the red LED 16, green LED 17, and blue LED 18 within the exposure time of the CCD 4 are individually calculated (step SC3). More specifically, the drive time Tr of the red LED 16 having the largest ratio of the total light emission time described above is used as the exposure time, and the drive times Tg and Tb of the green LED 17 and the blue LED 18 are calculated based on the exposure time Tr. Thereafter, the light emission control block 15 drives the LEDs 16, 17, 18 all at once as shown in FIG. 3, and continuously drives the LEDs 16, 17, 18 until the calculated times Tr, Tg, Tb are reached ( Step SC4).

  As a result, within the exposure time T of the CCD 4, the ratio of the individual light emission times of the LEDs 16, 17, 18 is controlled to the ratio set at the time of shipment from the factory (Rt: Gt: Bt), which is required for strobe light. The predetermined color temperature is ensured. Therefore, the same effects as those of the first and second embodiments can be obtained in this embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the present embodiment, as in the third embodiment, in the digital camera having the configuration shown in FIG. 1, the light emission control block 15 determines the LEDs 16, 17, and 18 based on the control of the MPU 8 in the flash photography mode. A drive current of a predetermined value is supplied to cause each of the LEDs 16, 17, and 18 to emit light, and the EEPROM 14 is caused to cause the MPU 8 to perform the strobe control shown in FIG. 8 different from the third embodiment. A program is stored.

Also in the present embodiment, when a trigger signal is sent from the operation key unit 12 (YES in step SD1), the MPU 8 reads the ratio data (Rt, Gt, Bt) described above from the EEPROM 14 (step SD2). The drive times (light emission times) Tr, Tg and Tb of the red LED 16, green LED 17 and blue LED 18 within the exposure time of the CCD 4 are individually calculated (step SD3). More specifically, the drive time Tr of the red LED 16 having the largest ratio of the total light emission time described above is set as the exposure time T, and the drive times Tg and Tb of the green LED 17 and the blue LED 18 are calculated based on the exposure time T. Furthermore, MPU 8 is red LED16 driving time (exposure time) one of the driving time _d G for driving in a time division green LED17 and blue LED18 in Tr, _{d B} and the driving interval _i G, and _{i B} Then, the light emission control block 15 continuously drives the red LED 16 within the exposure time T of the CCD 4 and calculates the green LED 17 and the blue LED 18 by the light emission control block 15 as shown in FIG. interval _i G, _i driving time _d G calculated at _B, and intermittently driven by _{d B} (step SD5).

  Thereby, within the exposure time T of the CCD 4, the ratio of the individual total light emission time (integral value of the portion where the current flows) of each LED 16, 17, 18 is set to the ratio (Rt: Gt: Bt) set at the time of factory shipment. Thus, the required predetermined color temperature is secured for the strobe light. Therefore, the same effect as the other embodiments described above can be obtained.

  Further, within the exposure time T of the CCD 4, the green LED 17 and the blue LED 18 are intermittently driven in a time-sharing manner. As a result, the light emission timings of the LEDs 16, 17, 18 are averaged. The change in the color temperature of the strobe light within the exposure time) is uniform. Therefore, as in the second embodiment described above, uniform color photography is possible even when photographing a subject with intense movement, and good photography is possible even with strobe photography when the subject moves severely. The result can be obtained.

  In each of the embodiments described above, the strobe 1 has the three primary colors LEDs 16, 17, and 18 of red (R), green (G), and blue (B) to obtain white strobe light. However, only two color LEDs may be used for LEDs, or multicolor LEDs may be used, and the number of LEDs of each emission color may be plural. In any case, the arrangement form of the plurality of LEDs is not particularly limited, and can be arbitrarily arranged, for example, arranged on a straight line or arranged on the same circumference. When strobe light with a color temperature other than white light is required, only two-color LEDs may be used, or only LEDs having a predetermined emission color may be selectively emitted from among multi-color LEDs. .

  In each of the embodiments described above, the present invention is applied to the strobe 1 built in the digital camera 2. However, the present invention is not limited to this, and the present invention is configured by itself, It can also be used for devices mounted on other devices such as cameras and digital cameras. Even in that case, the same effects as those of the above-described embodiments can be obtained. Further, the light emitting diodes 16, 17, and 18 are used as the light emitting elements constituting the strobe 1. However, in addition to the light emitting diodes, as described above, the light emitting color is emitted during the required light emitting operation period such as the exposure time. Other light emitting elements can be used as long as the ratio of the total light emission time for each can be controlled.

It is a block diagram of a digital camera common to each embodiment of the present invention. 4 is a flowchart illustrating a strobe control procedure by the MPU in the first embodiment. It is a timing chart which shows the drive timing of three color LED in the embodiment. It is a flowchart which shows the control procedure of the strobe by MPU in 2nd Embodiment. It is a timing chart which shows the drive timing of three color LED in the embodiment. It is a flowchart which shows the control procedure of the strobe by MPU in 3rd Embodiment. It is a timing chart which shows the drive timing of three color LED in the embodiment. It is a flowchart which shows the control procedure of the strobe by MPU in 4th Embodiment. It is a timing chart which shows the drive timing of three color LED in the embodiment.

Explanation of symbols

1 Strobe 2 Digital Camera 8 MPU
12 Operation key section 14 EEPROM
15 Light emission control block 16 Red LED
17 Green LED
18 Blue LED

Claims (8)

A flash device,
A plurality of light emitting elements having different emission colors;
Control means for causing the light emitting elements of the plurality of colors to emit light according to demand and controlling the ratio of the total light emitting time for each light emitting color during the light emitting operation period to a specific ratio determined according to each light emitting element; A flash device characterized by comprising.   The flash device according to claim 1, further comprising a driving unit that causes the light emitting elements of the plurality of colors to emit light by pulse driving, wherein the control unit controls the number of times of pulse driving by the driving unit for each emission color.   The control means averages the pulse drive timings of light emitting elements of light emission colors other than the light emission color for each light emission color within the drive time of the light emitting element of the light emission color having the largest ratio of the total light emission time. The flash device according to claim 2.   The driving means for driving the plurality of light emitting elements to emit light, and the control means controls the driving time of the light emitting elements of a plurality of colors driven by the driving means for each emission color. The flash device described.   The control means continuously drives a light emitting element having a light emission color having the largest ratio of the total light emission time to the drive means, and emits light emitting elements other than the light emission color for each light emission color within the continuous drive time. 5. The flash device according to claim 4, wherein the flash device is intermittently driven in a time-sharing manner.   The flash device according to claim 1, wherein the light emitting element is a light emitting diode.   A camera device comprising the flash device according to claim 1. A method for controlling the color temperature of light emitted by a flash device having light emitting elements of different colors with different emission colors,
Predetermining the ratio of the total emission time for each emission color according to each light emitting element,
When the light emitting elements of the plurality of colors are caused to emit light according to demand, the ratio of the total light emission time for each light emission color in the light emission operation period of the flash apparatus is controlled to the predetermined ratio. Control method.

Images