JP2007086178A - Electronic flash unit and imaging apparatus for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic flash unit for a camera having improved color reproducibility. <P>SOLUTION: In the electronic flash unit 600 for the camera, LEDs 62R, 62G, 62B and 62E of four colors of red(R), green(G), blue(B) and bluish green(E), respectively are used as an electronic flash unit light source 62. The light emission quantity of the LEDs 62R, 62G, 62B and 62E of four colors are individually controlled by a system controller 652 in accordance with the color temperature of an object field etc. The wavelength range of each color light beam emitted from each of LEDs 62R, 62G, 62B and 62E of the four colors is narrow, but, in addition to R, G and B three color light beams, light in color between G and B can be emitted, then, the electronic flash light of a wavelength range suitable to the spectral sensitivity characteristics of the camera can be emitted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a strobe device and an imaging device for a camera, and more particularly to a strobe device and an imaging device for a camera having a plurality of emission color strobe light sources.

  Conventionally, a strobe device (also called an electric flash) that emits a flash by applying a voltage to xenon gas is known.

On the other hand, recently, a strobe device for a camera having light emitting diodes (LEDs) of three colors of red (R), green (G), and blue (B) has been proposed (Patent Document 1).
JP 2002-116481 A

  By the way, in an imaging apparatus such as a digital camera or a digital video camera, R, G, B color filters are arranged in a predetermined arrangement structure (Bayer, G stripe R / G complete checkered, etc.) for each photocell to be photoelectrically converted. , R, G, and B colors, CCD (Charge Coupled Device) image sensors that have spectral sensitivity, CMOS (Complementary Metal-oxide Semiconductor) image sensors, and other color image sensors.

  The spectral sensitivities of the R, G, B photocells of this type of color imaging device are considerably widened, and the R, G, B colors partially overlap each other.

  On the other hand, the wavelength range of each emission color emitted from the R, G, and B LEDs is narrower than the spectral sensitivity range of the R, G, and B photocells of the color image sensor. For this reason, there is a problem that it is difficult to obtain R, G, and B intermediate color signal components from the color image sensor during strobe shooting using a strobe device using R, G, and B LEDs as a strobe light source.

  Some color image sensors have a four-color filter in which color filters of other colors (for example, emerald and cyan) are added in addition to the R, G, and B color filters. The strobe light of the B LED has a problem that it is difficult to obtain a signal component in a photocell having an emerald color filter.

  SUMMARY An advantage of some aspects of the invention is that it provides a camera strobe device and an imaging device capable of improving color reproducibility.

  In order to achieve the above object, a strobe device for a camera according to claim 1 includes a strobe light source having four or more colors including R, G, and B colors and intermediate colors of R, G, and B, each having a different emission color, And a light emission control means for controlling light emission of four or more strobe light sources.

  According to a second aspect of the present invention, in the strobe device for a camera according to the first aspect, the strobe light source is composed of light emitting diodes of four or more colors.

  According to a third aspect of the present invention, in the camera strobe device according to the second aspect, the light emitting diodes of four or more colors are R, G and B light emitting diodes, a purple light emitting diode, a blue-green light emitting diode, It is characterized by comprising a light emitting diode of one or more colors among a yellow light emitting diode and an orange light emitting diode.

  That is, although the wavelength range of the color emitted from the light emitting diode is narrow, in addition to the light of the three colors R, G, and B, it is possible to emit an intermediate color between the three colors of R, G, and B. Strobe light in a wavelength range suitable for spectral sensitivity characteristics can be emitted.

  4. The strobe device for a camera according to claim 1, further comprising color temperature setting means for manually setting a color temperature of strobe light, wherein the light emission control means includes the color temperature. The ratio of the light emission amounts of the four or more strobe light sources is controlled so that the color temperature set by the setting means is obtained.

  5. The strobe device for a camera according to claim 1, further comprising color temperature detection means for detecting a color temperature of an object field, wherein the light emission control means is configured to detect the color temperature. The ratio of the light emission amounts of the four or more strobe light sources is controlled so that the color temperature detected by the means is obtained.

  In other words, strobe light having the same color temperature as the color temperature of the object field can be emitted manually or automatically according to the color temperature of the object field.

  According to a sixth aspect of the present invention, in the strobe device for a camera according to any one of the first to third aspects of the present invention, the strobe device further includes a selection unit that selects a light emission color, and the light emission control unit is one of the four or more color strobe light sources. A strobe light source of one or more colors selected by the selection unit is caused to emit light.

  The invention according to claim 7 includes a color image sensor having spectral sensitivities for at least R, G, and B colors, and records a color image signal indicating a subject image obtained through the color image sensor on a recording medium. In the imaging apparatus, a strobe light source having four or more colors including R, G, and B colors and an intermediate color of R, G, and B that match the spectral sensitivity characteristics of the color imaging element, and the four colors. And a light emission control means for controlling the light emission of the strobe light source.

  According to the present invention, it is possible to improve color reproducibility during flash photography.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a camera strobe device and an imaging device according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an external appearance of an imaging apparatus (hereinafter referred to as “digital camera”) 10 to which the present invention is applied as viewed from the front side.

  In FIG. 1, the photographing lens 12 is composed of a plurality of optical lenses including a focus lens.

  The shutter button 401 is an operation means for inputting a shooting preparation instruction and a shooting start instruction, and has a two-stage stroke having a switch (S1 switch) that is turned on when half-pressed and a switch (S2 switch) that is turned on when fully pressed. It consists of a switch of the formula.

  The strobe device 60 has a four-color strobe light source 62 and can simultaneously emit light of a plurality of colors (for example, red, green, blue, and blue-green) toward a subject. That is, the strobe device 60 is a light emitting device that can emit light of a plurality of wavelengths simultaneously.

  The strobe light source 62 of the strobe device 60 includes a plurality of light emitting elements that emit light of different colors. For example, a strobe light source includes red, green, blue, and blue-green light emitting diodes (LEDs).

  The light emitting element constituting the strobe light source 62 is not particularly limited to a light emitting diode, and an organic material using an organic substance that emits light when a voltage is applied as long as it can emit light with a sufficient amount of light to be irradiated to a subject at the time of photographing. The strobe light source 62 may be configured by an EL (Electroluminescence) element, a plasma light emitting element that emits light using plasma, or the like.

  Since the plurality of light emitting elements constituting the strobe light source 62 are arranged adjacent to each other, light of a plurality of wavelengths (for example, red, green, blue, and blue-green light) is simultaneously emitted toward the subject. Sometimes it is generally perceived as one color by the human eye. Further, by changing the light emission amount for each light emitting element, that is, by changing the light emission balance in various ways, light of various colors is visually recognized by human eyes.

  FIG. 2 is a perspective view showing the external appearance of the digital camera 10 of FIG. 1 viewed from the back side.

  In FIG. 2, the liquid crystal monitor 52 is configured by a liquid crystal display (LCD) capable of color display.

  The mode selection switch 402 is a shooting mode for shooting a subject and recording image data on a recording medium such as a memory card, and a playback mode for playing back and displaying the image data recorded on the recording medium on the liquid crystal monitor 52. Is an operation means for selecting one of the modes.

  The light emission balance changeover switch 403 emits light with a predetermined standard light emission balance (normal light emission), or changes light emission balance from such normal light emission to emit light with a light emission balance suitable for the subject (balanced light emission). It is an operation means for switching whether to perform.

  The menu / OK key 404 is an operation means for inputting an instruction to display the menu on the liquid crystal monitor 52 and an instruction to confirm and execute the content selected on the menu.

  The cross key 405 is an operation means for inputting instructions in four directions, up, down, left, and right for selection on a menu.

  3A and 3B are front views showing examples of the strobe light source of the strobe device 60. FIG.

  The strobe light source 62a shown in FIG. 3A includes a red LED 62R that emits red (R) light, a green LED 62G that emits green (G), a blue LED 62B that emits blue (B), and blue-green ( E: Emerald) Blue-green LEDs 62E that emit light are provided one by one.

  The strobe light source 62b shown in FIG. 3B includes a plurality of red LEDs 62R, green LEDs 62G, blue LEDs 62B, and blue-green LEDs 62E. The numbers of the red LED 62R, the green LED 62G, the blue LED 62B, and the blue-green LED 62E do not have to be the same. For example, the LEDs 62R, 62G, 62B, and 62E are arranged in such a ratio that white light is emitted when they are fully emitted. Set up.

  FIG. 4 is a principal block diagram showing a specific example of the internal configuration of the digital camera 10 of FIG.

  The overall operation of the camera 10 is centrally controlled by a central processing unit (CPU) 70 according to a predetermined program.

  The operation unit 40 is the shutter button 401, the mode selection switch 402, the light emission balance changeover switch 403, the menu / OK key 404, the cross key 405, and other operation means shown in FIGS. Input signals from various operation means (401, 402, 403, 404, 405, etc.) of the operation unit 40 are input to the CPU 70, and the CPU 70 controls each unit of the digital camera 10 based on these signals.

  The photographing lens 12 is composed of a plurality of optical lenses including a focus lens. The aperture 14 changes the aperture value of the photographic lens 12 by changing the aperture diameter. The photographing lens 12 is driven by a lens driving unit 42, and the diaphragm 14 is driven by a diaphragm driving unit 44. Specifically, when the focus lens is driven, the in-focus distance changes, and when the aperture 14 is driven, the aperture value changes and the amount of exposure light changes.

  A subject image is formed on the light receiving surface of a color imaging device (hereinafter simply referred to as “CCD”) 16 such as a CCD (Charge Coupled Devices) through the photographing lens 12 and the diaphragm 14.

  A large number of photocells (light receiving elements) are two-dimensionally arranged on the light receiving surface of the CCD 16. Reflected light of the subject is incident on each photocell via color filters (for example, red (R), green (G), and blue (B) color filters). The subject image formed on the light receiving surface of the CCD 16 is converted into an amount of signal charge corresponding to the amount of incident light by each photocell and accumulated. The signal charge accumulated in this way is sequentially read out as a voltage signal corresponding to the signal charge by the read gate pulse applied from the CCD drive circuit 46. That is, the image signal for each color of R, G, and B is output from the CCD 16.

  In the present embodiment, the case where the CCD 16 as the imaging device has a photocell as a light receiving element for storing signal charges for each color of red (R), green (G), and blue (B) is taken as an example. As will be described, the present invention is not limited to this. For example, a color imaging element having photocells that accumulate signal charges for four colors obtained by adding blue-green (E) to R, G, and B may be used. .

  The CCD 16 has an electronic shutter function, and controls the charge accumulation time (shutter speed) of each photocell.

  A voltage signal as an image signal for each of the R, G, and B colors sequentially read from the CCD 16 is applied to a correlated double sampling circuit (CDS circuit) 18, where the image signals for each of the R, G, and B colors are provided. The sample is held and added to the A / D converter 20. The A / D converter 20 converts analog R, G, and B signals sequentially added from the CDS circuit 18 into digital R, G, and B signals and outputs them. The CCD drive circuit 46, the CDS circuit 18, and the A / D converter 20 are driven in synchronization with a timing signal applied from the timing generation circuit 22.

  The R, G, B color image signals output from the A / D converter 20 are temporarily stored in the memory 24, and then the R, G, B color image signals stored in the memory 24 are digitally stored. It is added to the signal processing circuit 26. The digital signal processing circuit 26 includes a synchronization circuit 28, an image correction circuit 30, a gamma correction circuit 32, a YC signal generation circuit 34, a memory 36, and the like.

  The synchronization circuit 28 converts the dot-sequential R, G, and B color image signals read from the memory 24 into simultaneous equations, and simultaneously converts the R, G, and B color image signals to the image correction circuit 30. Output.

  The image correction circuit 30 includes multipliers 30R, 30G, and 30B for increasing and decreasing the digital values of the image signals for the respective colors R, G, and B. The image signals for the colors R, G, and B are as follows: Added to the multipliers 30R, 30G, and 30B, respectively. A correction coefficient (gain value) is added from the CPU 70 to the other inputs of the multipliers 30R, 30G, and 30B, and the multipliers 30R, 30G, and 30B each multiply two inputs, and images corrected by this multiplication are corrected. Signals (R ′, G ′, B ′ signals) are output to the gamma correction circuit 32.

  The gamma correction circuit 32 changes the input / output characteristics so that the corrected image signals (R ′, G ′, B ′ signals) have desired gamma characteristics, and outputs them to the YC signal generation circuit 34. The YC signal creation circuit 34 creates a luminance signal Y and chroma signals Cr and Cb from the image signals for each color of R, G, and B subjected to gamma correction. The luminance signal Y and chroma signals Cr and Cb (YC signal) are stored in the memory 36 in the same memory space as the memory 24.

  Here, by reading the YC signal in the memory 36 and outputting it to the liquid crystal monitor 52, a through image, a captured still image, etc. can be displayed on the liquid crystal monitor 52.

  The YC signal after photographing is compressed into a predetermined format by the compression / expansion circuit 54 and then recorded on a recording medium 58 such as a memory card by the recording unit 56.

  Further, in the reproduction mode, the image data recorded on the recording medium 58 is decompressed by the compression / decompression circuit 54 and then output to the liquid crystal monitor 52 so that the reproduced image is displayed on the liquid crystal monitor 52. .

  Next, the spectral sensitivity characteristics of the CCD 16 and the light emission characteristics of the strobe device 60 will be described.

  FIG. 5 is a diagram illustrating spectral sensitivity characteristics of R, G, and B photocells of the CCD 16, and examples of wavelength ranges of the red LED 62R, the green LED 62G, the blue LED 62B, and the blue-green LED 62E that are the strobe light sources 62a.

  In FIG. 5, the spectral sensitivity characteristics (including lens characteristics) of R, G, and B photocells are indicated by dotted lines. As shown in the figure, the spectral sensitivities of the R, G, and B photocells are wide, and the R, G, and B colors partially overlap each other.

  The light emission characteristics of the red LED 62R, the green LED 62G, the blue LED 62B, and the blue-green LED 62E are indicated by solid lines, and the wavelength range is narrower than the spectral sensitivity characteristics of the R, G, and B photocells.

  As shown in FIG. 5, the blue-green light emitted from the blue-green LED 62 </ b> E can emit an intermediate color between the spectral sensitivities of the G and B photocells.

  In this embodiment, four color red LED 62R, green LED 62G, blue LED 62B, and blue-green LED 62E are used as the strobe light source 62a, but purple, yellow and orange LEDs are used as shown in FIG. It can also be used.

  FIG. 6 shows the spectral sensitivity characteristics of a CCD having blue-green (E) photocells as well as R, G, and B photocells, and a red LED 62R, a green LED 62G, a blue LED 62B, and a strobe light source 62a. It is a figure which shows an example of the wavelength range of blue-green LED62E.

  That is, the spectral sensitivity characteristic of the photocell of E is added to the graph shown in FIG. As shown in the figure, blue-green light emitted from the blue-green LED 62E can be detected with high sensitivity by the E photocell.

  As described above, the strobe device 60 according to the present invention can emit strobe light suitable for the spectral sensitivity characteristics of the camera by using LEDs of four or more colors.

  Next, an outline of the light emission control of the strobe device 60 will be described.

  The CPU 70 controls the light emission of the strobe device 60 according to the light emission mode (normal light emission or balanced light emission) set by the light emission balance changeover switch 403 of the operation unit 40.

  Specifically, the CPU 70 controls the light emission balance of each LED 62R, 62G, 62B, and 62E constituting the strobe light source 62 of the strobe device 60 for each LED 62R, 62G, 62B, and 62E. Control. Such light emission balance control will be described in detail later.

  Next, an outline of image processing such as white balance correction will be described.

  In FIG. 4, R, G, B images for each divided area obtained by dividing one screen into a plurality of areas (8 × 8) from R, G, B color image signals temporarily stored in the memory 24. The average integrated value for each signal color is obtained. The average integrated value of the image signals for each of the R, G, and B colors for each divided area is calculated by the integrating circuit 48 and provided to the CPU 70. Note that multipliers 50R, 50G, and 50B are provided between the integrating circuit 48 and the CPU 70, and an adjustment gain value for adjusting variation of devices is added to the multipliers 50R, 50G, and 50B. It has become.

  The CPU 70 supplies the R, G, and B given to the image correction circuit 30 of the digital signal processing circuit 26 based on the average accumulated values of the R, G, and B image signals for each divided area given from the integrating circuit 48 during normal light emission. The correction coefficients (gain values) for the G and B colors are calculated, and the correction coefficients are supplied to the image correction circuit 30 of the digital signal processing circuit 26.

  On the other hand, the CPU 70 controls the digital signal processing circuit 26 based on the amount of light emitted from each of the LEDs 62R, 62G, 62B, and 62E constituting the strobe light source 62 of the strobe device 60 at the time of balanced light emission that switches the light emission balance to normal light emission. R, G, and B correction coefficients (gain values) to be given to the white balance correction circuit 30 are calculated, and the correction coefficients are given to the image correction circuit 30 of the digital signal processing circuit 26.

  FIG. 7 is a principal block diagram showing a functional configuration of the digital camera 10 according to the present invention.

  7, the digital camera 10 mainly includes an imaging unit 116, a correction unit 126, a signal level measurement unit 148, a display unit 152, a recording unit 56, a strobe light source 62, a signal level ratio calculation unit 171, and a light emission amount ratio calculation unit 172. The light emission balance switching unit 173 and the correction coefficient calculation unit 174 are included.

  The correspondence between the components of the digital camera 10 having the functional configuration shown in FIG. 7 and the components of the digital camera 10 having the basic configuration shown in FIG. 4 will be briefly described. The imaging unit 116 is mainly configured by the CCD 16 of FIG. The correction unit 126 is mainly configured by the digital signal processing circuit 26 in FIG. 4, the signal level measurement unit 148 is mainly configured by the integration circuit 48 in FIG. 4, and the display unit 152 is mainly configured by the liquid crystal monitor 52 in FIG. The signal level ratio calculation unit 171, the light emission amount ratio calculation unit 172, the light emission balance switching unit 173, and the correction coefficient calculation unit 174 are mainly configured by the CPU 70 of FIG.

  The spectral sensitivity characteristics of the imaging unit 116 are determined by differences in characteristics such as a color filter, a photocell, and a circuit that takes in charges accumulated in the photocell. Specifically, the spectral sensitivity characteristic of the imaging unit 116 is expressed by the sensitivity for each color of R, G, and B. Specifically, for example, it is represented by a signal level ratio (R: G: B) for each color of R, G, and B when the amount of light incident on the imaging unit 116 is R: G: B = 1: 1: 1. Is done.

  The signal level measuring unit 148 measures the level (signal level) of the image signal for each of R, G, and B colors. Specifically, for example, the peak value or average value of the image signal for each color of R, G, and B is used as such a signal level. In the present embodiment, the peak value of the average integrated value for each R, G, B color measured for each divided area by the integrating circuit 48 of FIG. 4 is used as the signal level.

  The signal level ratio calculation unit 171 calculates a signal level ratio (ratio between the R signal level, the G signal level, and the B signal level) based on the signal level for each color R, G, and B measured by the signal level measurement unit 148. To do. Such a signal level ratio is used as a value indicating the color distribution ratio of the external light or the color distribution ratio of the subject (that is, the color distribution ratio of the reflected light of the subject). That is, the signal level ratio calculation unit 171 functions as a means for calculating the color distribution ratio of outside light and a means for calculating the color distribution ratio of the subject.

  The light emission amount ratio calculation unit 172 calculates the light emission amount ratios of the LEDs 62R, 62G, 62B, and 62E constituting the strobe light source 62 based on the signal level ratio calculated by the signal level ratio calculation unit 171. Specifically, as the light emission amount ratio, the ratio of the light emission amount of the red (R) LED 62R, the light emission amount of the green (G) LED 62G, the light emission amount of the blue (B) LED 62B, and the light emission amount of the blue-green (E) LED 62E. calculate. In this way, the light emission balance of the strobe light source 62 is determined by calculating the light emission amount ratio of the LEDs 62R, 62G, 62B, and 62E.

  The light emission balance switching unit 173 switches the light emission balance of the strobe light source 62 by causing the LEDs 62R, 62G, 62B, and 62E of the strobe light source 62 to emit light at the light emission amount ratio calculated by the light emission amount ratio calculating unit 172.

  When switching the light emission balance of the strobe light source 62 in this way, the light emission balance switching unit 173 emits light from the strobe light source 62 within a range in which the image signals for each of the R, G, and B colors output from the imaging unit 116 are not saturated. Switch the balance.

  For example, as shown in FIG. 8, if the signal level ratio is R: G: B = 1: 4: 2, the level of the R signal is quadrupled with the G signal having the highest signal level as a reference (1 ×). And the light emission amount ratio of the LEDs 62R, 62G, 62B, and 62E constituting the strobe light source 62 is determined so that the level of the B signal is doubled. Here, the light is emitted so that the color with a lower signal level (R in the example shown in FIG. 8) becomes stronger.

  In order to facilitate understanding of the present invention, it is assumed that only LEDs R, G, and B of three colors 62R, 62G, and 62B emit light, and when the light emission amount of a specific color LED (for example, 62R) is increased n times, the LED It is assumed that the level of the image signal (for example, R signal) of the same color as the color (for example, R) is n times. Then, when the signal level ratio is R: G: B = 1: 4: 2, as shown in FIG. 6, the light emission balance is set so that the light emission amount ratio becomes R: G: B = 4: 1: 2. Switch.

  Switching of the light emission balance of the strobe light source 62 based on such a signal level ratio is performed only when the light emission balance changeover switch 403 in FIG. 2 is on, while when the light emission balance changeover switch 403 is off. As the normal light emission, the light emission amounts of the LEDs 62R, 62G, 62B, and 62E are set so that the entire flash light source 62 emits white light. For example, when only the LEDs 62R, 62G, and 62B of three colors R, G, and B emit light, the ratio of the light emission amounts is set to R: G: B = 1: 1: 1.

  In order to facilitate understanding of the present invention, the case where only the LEDs R, G, and B of the three colors 62R, 62G, and 62B emit light has been described. However, in order to improve the color reproducibility, green ( The blue-green (E) LED 62E having a wavelength between the wavelength of G) and the wavelength of blue (B) is also preferably caused to emit light.

  Based on the light emission amount ratio calculated by the light emission amount ratio calculation unit 172, the correction coefficient calculation unit 174 calculates a correction coefficient for each R, G, and B color that is multiplied by the image signal for each color of R, G, and B. To do.

  The correction unit 126 multiplies the R, G, and B color correction coefficients calculated by the correction coefficient calculation unit 174 by the R, G, and B color image signals, thereby outputting the image signal output from the imaging unit 116. Correct.

  The image signal corrected by the correction unit 126 is displayed on the display unit 152 and recorded on a predetermined recording medium by the recording unit 56.

  The present invention has been described above by taking the digital camera 10 including the strobe device 60 having the strobe light source 62 as an example. Hereinafter, the strobe device provided with the strobe light source 62 and switching the light emission balance of the strobe light source 62 will be described. ,explain.

  FIG. 9 is an external view of the strobe device 600.

  In FIG. 9, the strobe device 600 includes a strobe main body 620 provided with a hot shoe 622 on the lower surface, and a strobe light emitting unit 630 disposed on the top of the strobe main body 620.

  On the front surface of the strobe main body 620, a photo sensor 624 (a photo sensor with a red filter 624R, a photo sensor with a green filter 624G, a photo sensor with a blue filter 624B, and A photo sensor 624E) with a blue-green filter is provided, and a change-over switch 626 that switches between a manual mode for manually setting the light emission balance (light emission amount ratio) of the strobe light and an auto mode for automatically setting the light emission balance is provided on the side surface. And a light emission balance setting volume 628 for setting the light emission balance of the strobe light in the manual mode.

  In FIG. 9, reference numeral 632 denotes a Fresnel lens provided in the light emission window of the strobe light emission unit 630, and 634 denotes a light receiving sensor for strobe light adjustment.

  FIG. 10 is a rear view of the strobe device 600. On the back of the strobe device 600, a light emission balance storage switch 621 (621-1 to 621-3), display lamps L1 to L3, and a light emission balance read switch 623 are provided. When any switch is operated, the light emission balance storage switch 621 has a light emission balance (light emission amount ratio) suitable for the color distribution ratio (color temperature) of the object scene detected by the photosensor 624 when the switch is operated. The calculated light emission balance (light emission amount ratio) is stored in a nonvolatile memory (EEPROM) 625 (see FIG. 11) in the strobe device 600. In this embodiment, three types of light emission balances can be stored by the light emission balance storage switches 621-1 to 621-3.

  The light emission balance read switch 623 is a switch for reading the light emission balance stored based on the switch operation of the light emission balance storage switches 621-1 to 621-3. The stored light emission balance is sequentially selected and read based on the switch operation of 621-3. The display lamps L1 to L3 are provided corresponding to the light emission balance storage switches 621-1 to 621-3, and the display lamps are lit with a light amount corresponding to the currently selected light emission balance.

  The strobe light emitting unit 630 is provided with a strobe light source 62a shown in FIG. 3A or a strobe light source 62b shown in FIG.

  FIG. 11 is a block diagram showing an example of the internal configuration of the strobe device 600.

  The strobe device 600 includes the light emission balance storage switch 621, the light emission balance reading switch 623, the photo sensor 624 for detecting the color distribution ratio (color temperature), the EEPROM 625, the changeover switch 626, the light emission balance setting volume 628, the strobe adjustment. In addition to the light receiving sensor 634 and the LED group 62 (strobe light source), the battery 640, the voltage up-converter 642, the large-capacitance capacitor 644, the operational amplifiers 63R, 63G, 63B, 63E, the system controller 652, the dimming circuit 654 And a temperature sensor 656 are provided.

  The system controller 652 controls the strobe device 600 in an integrated manner, controls the voltage up-converter 642, boosts the voltage of the battery 640 (for example, 6V) to about 10V, and charges the capacitor 644 with the boosted voltage. The capacitor 644 is charged for a long time of about 2 to 5 seconds, for example, and can continuously supply current to the LED group 62 for 1/60 seconds (about 16 milliseconds) or longer.

  The electrical energy stored in the capacitor 644 is supplied to the LEDs 62R, 62G, 62B, and 62E of the R, G, B, and E via the operational amplifiers 63R, 63G, 63B, and 63E, but the system controller 652 includes the operational amplifier 63R. , 63G, 63B, and 63E, and the light emission time and light emission amount of the LEDs 62R, 62G, 62B, and 62E of R, G, B, and E are controlled.

  The system controller 652 inputs a light emission signal synchronized with the shutter release via a hot shoe 622 (see FIG. 9) from a camera (not shown), and determines the entire strobe light emission amount such as a guide number by serial communication. Information is being captured. Further, when the changeover switch 626 is switched to the manual side, the system controller 652 controls the flash light emission balance so that the light emission balance set by the light emission balance setting volume 628 is obtained, or the changeover switch 626 is set to the auto side. , The flash light emission balance (light emission amount ratio) so that the light emission amount ratio is suitable for the color distribution ratio (color temperature) of the object scene detected by the photosensor 624 for detecting the color distribution ratio. To control. The color distribution ratio detection sensor is not limited to this embodiment, and various sensors can be used. In this embodiment, the color distribution ratio is detected based on the intensity ratio of the red (R), green (G), blue (B), and blue-green (E) components of light. The color distribution ratio may be detected based on the intensity ratio of the R, G, and B components of light or the ratio of the intensity of the R, B components of light.

  Further, when the light emission balance storage switch 621 is operated, the system controller 652 sets the color distribution ratio based on the color distribution ratio of the object scene detected by the photosensor 624 for detecting the color distribution ratio when the switch is operated. A suitable light emission balance (light emission amount ratio) is calculated and stored in the EEPROM 625. On the other hand, when the light emission balance read switch 623 is operated, the light emission balance (light emission amount ratio) stored in the EEPROM 625 is read out. The light emission balance of the strobe light is controlled so that the read light emission balance is obtained. Thus, for example, the light emission balance suitable for the color distribution ratio such as a spotlight in a ceremonial hall, ceiling lighting, studio lighting, etc. is registered in the EEPROM 625 by operating the light emission balance storage switch 621, and the light emission balance read switch 623 is set before photographing. A desired light emission balance registered in the EEPROM 625 is read out by operating, and the strobe light with the read light emission balance can be emitted.

  Since the light amount of the LED varies depending on the ambient temperature, a temperature sensor 656 for detecting the ambient temperature of the LED group 62 is provided. The system controller 652 detects the ambient temperature of the LED group 62 detected by the temperature sensor 656. The current control to the LED group 62 is performed so that the required amount of light emission can be obtained regardless of the ambient temperature.

  Next, the operation of the system controller 652 will be described with reference to the timing chart shown in FIG.

  First, the system controller 652 outputs a signal for starting charging to the voltage up-converter 642 by a strobe on signal (FIG. 12A) for performing strobe shooting, starts charging the capacitor 644, and charges the capacitor 644. Is completed, the charging operation by the voltage up-converter 642 is stopped (FIGS. 12B and 12C).

  Thereafter, when the shutter button is half-pressed, a standby state is entered (FIG. 12D), and information for determining the entire flash emission amount such as a guide number is captured. When the changeover switch 626 is switched to the auto mode, the color distribution ratio of the object scene is read from the photosensor 624 for detecting the color distribution ratio, and the changeover switch 626 is switched to the manual mode. Reads the light emission balance set manually, and if the light emission balance read switch 623 is operated, reads the light emission balance from the EEPROM 625 (FIG. 12E).

  The system controller 652 determines the flash emission amount based on the captured information, outputs a reference value for adjusting the flash emission amount to obtain the flash emission amount to the dimming circuit 654, and displays the color of the object scene. Based on the distribution ratio, the ratio of the light emission amounts of the R, G, and B LEDs 62R, 62G, 62B, and 62E is determined so as to emit light having a light emission balance suitable for the color distribution ratio, and the ratio corresponds to this ratio. R, G, and B emission levels are set (FIG. 12 (F)).

  Next, when the shutter button is fully pressed and the shutter is opened, a light emission signal synchronized with the shutter opening is input, and control signals indicating the set R, G, and B light emission levels are respectively input to the operational amplifiers 63R, 63G, 63B, Output to 63E positive input. On the other hand, signals corresponding to the current values flowing through the LEDs 62R, 62G, 62B, and 62E are added to the negative inputs of the operational amplifiers 63R, 63G, 63B, and 63E. The operational amplifiers 63R, 63G, 63B, and 63E Control is performed so that constant currents corresponding to the R, G, B, and E emission levels flow through the LEDs 62R, 62G, 62B, and 62E.

  As a result, strobe light is emitted from the LED group 62 with a light emission balance suitable for the color distribution ratio of the object scene as a whole (FIG. 12G).

  When strobe light is emitted from the LED group 62, the light control circuit 654 detects the light emission amount via the light receiving sensor 634 for strobe light control. When the detected light emission amount matches the reference value for adjusting the light emission amount, a light emission stop signal is output to the system controller 652 in order to stop the light emission. When receiving the light emission stop signal from the dimming circuit 654, the system controller 652 outputs a control signal for stopping the light emission of the LED group 62 to the operational amplifiers 63R, 63G, 63B, and 63E. Thereby, the electric current which flows into LED group 62 is interrupted | blocked, and the light emission of LED group 62 stops.

  FIG. 13 is a perspective view showing the external appearance of another example of an external strobe device 60 that can be attached to and detached from the digital camera 10.

  A strobe device 6000 shown in FIG. 13 is a strobe light source composed of LEDs for R, G, B, and E colors according to instructions input from a digital camera via a communication contact 65 shown in FIG. 62 emits light.

  Note that the case where the strobe light source 62 is composed of light emitting elements of four colors of red (R), green (G), blue (B), and blue-green (E) has been described as an example. It is not particularly limited to the case of four colors of red, green, blue and blue-green. The strobe light source 62 may be composed of light emitting elements of three colors (for example, red, green, and blue), or may be light emitting elements of four colors that are different from red, green, blue, and blue-green. Alternatively, it may be a case where the light emitting element is composed of five or more colors. Furthermore, the light emission of a desired color among the light emitting elements of four or more colors may be appropriately selected by manual operation.

  Further, the digital camera has been described as an example of the imaging apparatus according to the present invention. However, the imaging apparatus according to the present invention includes various imaging apparatuses that capture a subject. For example, it includes all imaging devices such as a mobile device with a camera, a surveillance camera fixedly installed, and a camera mounted on a moving body such as a vehicle.

  Furthermore, the camera to which the strobe device 600 described with reference to FIG. 9 and the like is applied is not limited to a digital camera, and can also be applied to a silver salt camera. Some photographic films used in silver halide cameras have a cyan (blue-green) photosensitive layer in addition to the R, G, and B photosensitive layers, and emit this type of strobe light. It can emit strobe light that matches the photosensitivity of the film.

  As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited by the configurations, numerical values, drawings, and the like described in the present specification, and various design changes can be made without departing from the gist of the present invention. Of course, you can make improvements.

FIG. 1 is a perspective view showing an appearance of an example of a digital camera having a built-in strobe device as viewed from the front side. FIG. 2 is a perspective view showing an appearance of the digital camera of FIG. 1 viewed from the back side. FIG. 3 is a front view showing an example of a strobe light source of the strobe device. FIG. 4 is a block diagram showing the basic internal configuration of the digital camera. FIG. 5 is a diagram showing an example of spectral sensitivity characteristics of CCD R, G, and B photocells and emission characteristics of LEDs. FIG. 6 is a diagram showing an example of spectral sensitivity characteristics of R, G, B, and E photocells of a CCD and light emission characteristics of each LED. FIG. 7 is a principal block diagram showing a functional configuration of the digital camera according to the present invention. FIG. 8 is a diagram used for explaining that strong light emission is performed within a range in which the levels of the image signals of R, G, and B colors are not saturated. FIG. 9 is a perspective view showing an appearance of an example of a strobe device that can be attached to and detached from the digital camera. FIG. 10 is a rear view of the strobe device of FIG. FIG. 11 is a block diagram showing the internal structure of the strobe device of FIG. 13 is a timing chart for explaining the operation of the strobe device of FIG. 12. FIG. 13 is a perspective view showing the appearance of another example of a strobe device that can be attached to and detached from a digital camera. FIG. 14 is a diagram showing an example of communication contacts with the electronic camera in the strobe device of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 12 ... Shooting lens, 14 ... Aperture, 16 ... CCD (imaging part), 26 ... Digital signal processing circuit (correction part), 24, 36 ... Memory, 40 ... Operation part, 48 ... Integration circuit (signal level measurement part), 52 ... Liquid crystal monitor (display unit), 54 ... Compression / decompression circuit, 56 ... Recording unit, 58 ... Recording medium (recording medium), 60, 600 ... Strobe device, 62 ... Strobe light source (LED group), 62R, 62G, 62B, 62E ... LED, 70 ... CPU, 116 ... imaging unit, 126 ... correction unit, 148 ... signal level measurement unit, 152 ... display unit, 171 ... signal level calculation unit, 172 ... light emission amount ratio calculation unit, 173 ... light emission Balance switching unit, 174 ... correction coefficient calculation unit

Claims (7)

4 or more strobe light sources with different emission colors including R, G, B colors and R, G, B intermediate colors,
Light emission control means for controlling the light emission of the strobe light sources of four or more colors;
A strobe device for a camera characterized by comprising:   2. The strobe device for a camera according to claim 1, wherein the strobe light source is composed of light emitting diodes of four or more colors.   The light emitting diodes of four or more colors are composed of light emitting diodes of three colors of R, G, and B and light emitting diodes of one or more colors among purple light emitting diodes, blue green light emitting diodes, yellow light emitting diodes, and orange light emitting diodes. The camera strobe device according to claim 2, wherein   A color temperature setting means for manually setting a color temperature of the strobe light, wherein the light emission control means is a ratio of light emission amounts of the four or more strobe light sources so as to be a color temperature set by the color temperature setting means; 4. The strobe device for a camera according to claim 1, wherein the electronic flash is controlled.   Color temperature detection means for detecting the color temperature of the object scene is provided, and the light emission control means sets the ratio of the light emission amounts of the four or more strobe light sources so as to be the color temperature detected by the color temperature detection means. 4. The strobe device for a camera according to claim 1, wherein the strobe device is controlled.   A light emitting color selecting unit is provided, and the light emission controlling unit causes one or a plurality of color strobe light sources selected by the selecting means to emit light among the four or more color strobe light sources. Item 4. A camera strobe device according to any one of Items 1 to 3. In an imaging apparatus that includes a color imaging device having spectral sensitivity in at least R, G, and B colors, and that records a color image signal indicating a subject image obtained through the color imaging device on a recording medium.
A strobe light source having four or more colors including R, G, and B colors and R, G, and B intermediate colors that match the spectral sensitivity characteristics of the color image sensor, each having a different emission color;
Light emission control means for controlling the light emission of the strobe light sources of four or more colors;
An imaging apparatus comprising:

Images