JP2006138900A - Illuminator for photography and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator for photography which restrains the irregular color of illuminating light after correcting the color temperature thereof. <P>SOLUTION: The light emitting body of the white light emitting part of the illuminator 30 is constituted of a xenon discharge tube 32, and the light emitting body of a color temperature correcting light emitting part is constituted of an LED group 42r (1 to 3) emitting red component light, an LED group 42g (1 to 3) emitting green component light and an LED group 42b (1 to 3) emitting blue component light, so as to correct the color temperature of the illuminating light by the xenon discharge tube 32 with LED light. An irradiation range 32A (referring to Figure 7) by the xenon discharge tube 32 is made wider than a photographing range, and an irradiation range 42A (Figure 7) by the LED group 42r (1 to 3), the LED group 42g (1 to 3) and the LED group 42b (1 to 3) includes the irradiation range 32A (Figure 7) by the xenon discharge tube 32 and made much wider than the irradiation range 32A (Figure 7). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an illumination device that illuminates a subject during photographing.

  2. Description of the Related Art An illumination device that illuminates a subject at the time of shooting is known that includes a plurality of light sources (see Patent Document 1). The illumination device described in Patent Document 1 includes an LED that emits red light and an LED that emits blue light in order to correct the color temperature of flash light emitted from a discharge-type light source such as a xenon lamp. Then, one or both of the red LED and the blue LED are controlled to be turned on according to the color temperature correction amount.

Japanese Patent Laid-Open No. 10-206942

  In general, the luminance of illumination light from a light source is lower in the peripheral part of the irradiation range than in the central part of the irradiation range. When the brightness of the color temperature correction light from the light source for color temperature correction is low in the peripheral part of the irradiation range, it is observed as color unevenness between the central part and the peripheral part of the irradiation range. Such color unevenness has a greater sense of incongruity felt by humans than the luminance difference between the central portion and the peripheral portion of the irradiation range caused by illumination light (light from a xenon lamp, white LED, or the like).

The illumination device for photographing according to the invention described in claim 1 includes an illumination light emitting unit having a first irradiation range wider than at least the photographing range, and a second lighter including the first irradiation range and wider than the first irradiation range. A color temperature correction light emitting unit having an irradiation range, and a light emission control means for controlling the light emission of the color temperature correction light emitting unit so as to correct the color temperature of the illumination light by the illumination light emitting unit according to a color temperature correction instruction. It is characterized by providing.
In the photographing illumination device according to claim 1, the light emission control means may be configured to change the second irradiation range in accordance with the focal length of the photographing lens.
In the photographing illumination device according to claim 1, the light emission control means may be configured to fix the second irradiation range to an irradiation range corresponding to the photographing range when the wide-angle photographing lens is used.
The illuminating device for photographing according to any one of claims 1 to 3, wherein the color temperature correction light emitting unit may be configured to include an LED that emits at least single color component light.
The illuminating device for photographing according to any one of claims 1 to 3, wherein the color temperature correction light emitting unit may be configured to include a surface light emitting element that emits at least monochromatic component light.
The illuminating device for photographing according to any one of claims 1 to 3, wherein the color temperature correction light emitting unit may be configured to include an organic EL that emits at least monochromatic component light.
According to a seventh aspect of the present invention, there is provided a camera comprising the photographing illumination device according to any one of the first to sixth aspects.

  According to the present invention, the color temperature of the illumination light is corrected with the color temperature correction light that irradiates a wider range (second irradiation range) than the illumination light that irradiates a wider range (first irradiation range) than the photographing range. Thus, the luminance difference generated between the central portion and the peripheral portion of the photographing range can be suppressed to be smaller than the luminance difference of the color temperature correction light generated between the central portion and the peripheral portion of the second irradiation range. Thereby, a uniform color temperature correction effect can be obtained in the photographing range, and color unevenness of the illumination light after the color temperature correction can be suppressed.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a camera system equipped with a lighting device according to an embodiment of the present invention. In FIG. 1, a replaceable photographing lens 20 is attached to the camera body 10. A release button 11 is provided at the upper left portion when viewed from the subject side of the camera body 10, and an illumination device 30 is attached to an accessory shoe (not shown) disposed at the upper center of the camera body 10.

  FIG. 2 is a block diagram for explaining a main configuration of the camera system of FIG. In FIG. 2, the illumination device 30 includes a xenon (Xe) discharge tube 32, a main capacitor (MC) 33, a voltage detection circuit 34, an LED (light emitting diode) 42, and a current supply circuit 43. The lighting device 30 is provided with a timing signal for instructing the start and end of light emission of the xenon discharge tube 32 and the LED 42 via the communication terminal 31 provided in the accessory shoe, a signal for instructing the amount of light emission, and light emission preparation (during charging). ) And a signal indicating that the light emission preparation is completed, and the like are transmitted to and received from the CPU 101. In addition, when the setting which prohibits the light emission by the illuminating device 30 to the camera main body 10 is performed, it is comprised so that CPU101 may not output the signal which instruct | indicates light emission to the illuminating device 30. FIG.

  The CPU 101 is configured by an ASIC or the like. The CPU 101 inputs a signal output from each block described later, performs a predetermined calculation, and outputs a control signal based on the calculation result to each block.

  The subject luminous flux that has entered the camera body 10 through the photographing lens 20 (FIG. 1) is guided to an imaging device (not shown) configured by a CCD image sensor, a CMOS image sensor, or the like via the shutter unit 105. The shutter unit 105 opens the shutter curtain at a predetermined timing in accordance with a command from the CPU 101 during shooting, and closes the shutter curtain when an exposure time corresponding to the shutter speed has elapsed.

  The operation member 107 includes a release switch interlocked with the release button 11 (FIG. 1) and an operation switch group for performing various settings, and outputs an operation signal corresponding to the operation content to the CPU 101. For example, a setting operation signal is output to the CPU 101 in accordance with setting operations such as light emission permission / light emission prohibition and red-eye reduction light emission for the lighting device 30.

  The distance measuring device 102 detects the adjustment state of the focal position by the photographing lens 20 and outputs a detection signal to the CPU 101. The focus adjustment information is acquired by, for example, a known phase difference detection method. Specifically, two focus detection light beams incident through different regions of the photographing lens 20 are imaged on an image sensor array A and an image sensor array B (not shown), respectively. A pair of subject images formed on the image sensor arrays A and B approach each other in a so-called front pin state in which the photographing lens 20 forms a sharp image of the subject before the planned focal plane, and conversely behind the planned focal plane. In a so-called rear pin state that connects sharp images of the subject, they move away from each other. When focusing a sharp image of the subject on the planned focal plane, the pair of subject images on the image sensor arrays A and B relatively match. Therefore, the focus adjustment state of the photographic lens 20, that is, the defocus amount can be obtained by obtaining the relative positional deviation amount between the pair of subject images.

  The CPU 101 sends a command to the lens driving unit 104 to drive a focus lens (not shown) in the photographing lens 20 forward and backward in the optical axis direction according to the defocus amount, thereby adjusting the focal position of the photographing lens 20. The focus detection signal from the distance measuring device 102 is distance information corresponding to the distance to the main subject (shooting distance).

  The photometric device 103 detects the amount of subject light through the photographing lens 20 and outputs a detection signal to the CPU 101. The CPU 101 calculates subject luminance using the detection signal, and performs exposure calculation using the calculated luminance information.

  FIG. 3 is a diagram illustrating the optical system of the illumination device 30. A plurality of surface light emitting elements (LEDs 42) are mounted on the substrate 43 in an array. By using a surface light emitting element, light can be irradiated over a wide range. The light emitted from the LED 42 is condensed by the condenser lenses L2b and L2a and projected toward the subject via the projection lens L1. On the other hand, the light emitted from the xenon discharge tube 32 is projected toward the subject via the Fresnel lens L3.

  FIG. 4 is an enlarged view of the substrate 43 and the LED 42. In FIG. 4, the LED group that emits red component (R) light includes three light emitting elements 42r1 to 42r3. An LED group that emits light of a green component (G) is configured by three light emitting elements 42g1 to 42g3. An LED group that emits light of a blue component (B) is configured by three light emitting elements 42b1 to 42b3. These LED groups are arranged so that the colors emitted by the respective elements are arranged alternately. The LED groups 42r1 to 42r3, the LED groups 42g1 to 42g3, and the LED groups 42b1 to 42b3 are configured to be turned on and off for each LED group (that is, for each emission color).

  In the present embodiment, the xenon discharge tube 32 is mainly caused to emit light while the lighting device 30 is allowed to emit light. When the LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3) are set to a light emission mode for correcting the color temperature of illumination light by the xenon discharge tube 32 Make it emit light. The light emission mode for performing color temperature correction is set by, for example, menu setting on the camera body 10 side or operation by the operation member 107.

  FIG. 5 is a detailed block diagram of the illumination device 30. The lighting device 30 includes a booster circuit 35, a voltage detection circuit 34, a main capacitor 33, a white light emitting unit, a color temperature correction light emitting unit, and a dimming / boosting / brightness control circuit 41, and a battery E It is driven by the power supplied from The white light emitting unit includes a xenon discharge tube 32 and a light emission control circuit 39. The color temperature correction light emitting unit includes an LED group 42r (1-3), an LED group 42g (1-3), an LED group 42b (1-3), and a current supply circuit that supplies a predetermined current to each LED group. 40. The LED groups 42r, 42g, and 42b for each color correspond to the LED 42 in FIG.

  In FIG. 5, when a main switch (not shown) of the lighting device 30 is turned on and a signal instructing the start of boosting is input to the lighting device 30 via the terminal 31, a command of the dimming / boosting / luminance control circuit 41 is provided. As a result, the booster circuit 35 boosts the voltage of the battery E (for example, 330 V). The main capacitor 33 is charged with the boosted voltage. When the charging voltage of the main capacitor 33 reaches a predetermined voltage (for example, 270 V), the voltage detection circuit 34 turns on a pilot lamp (not shown) and sends a signal indicating that the light emission preparation is completed via the terminal 31 to the CPU 101 of the camera body 10. (FIG. 2).

  The xenon discharge tube 32 is controlled to discharge as follows. When a signal instructing the start of light emission is transmitted from the CPU 101 of the camera body 10 via the terminal 31, the light emission control circuit 39 generates a trigger voltage and applies this trigger voltage to the trigger electrode 32T of the xenon discharge tube 32. To do. Light emission starts in the xenon discharge tube 32 by the applied trigger voltage, and the xenon discharge tube 32 flashes using this light emission as a trigger. That is, the electrical energy stored in the main capacitor 33 is discharged in the xenon discharge tube 32.

  The xenon discharge tube 32 starts to emit light as soon as the trigger voltage is applied, and the emission intensity rises to the maximum value. The emitted light intensity decreases as the stored energy in the main capacitor 33 decreases, and the light emission ends when the stored energy in the main capacitor 33 becomes empty. In general, the time until the light emission intensity is reduced to ½ of the maximum value is called a flash time, and the time until the discharge light emission ends is called the total light emission time. In actual photographing, dimming light emission for controlling the light emission amount is performed based on an integrated value of detection signals detected by a dimming photometry device (not shown). In this case, the power supply to the xenon discharge tube 32 is stopped before the total emission time elapses, whereby the discharge light emission in the xenon discharge tube 32 is stopped, and the light amount emitted from the xenon discharge tube 32 is a predetermined light amount. Controlled. A circuit for stopping the light emission of the xenon discharge tube 32 is omitted in FIG.

  The LED groups 42r (1-3), the LED groups 42g (1-3), and the LED groups 42b (1-3) are controlled to be turned on in accordance with the light emission instruction from the CPU 101 as follows. When a signal for instructing the start of light emission and a signal for instructing the amount of light are transmitted from the CPU 101 of the camera body 10 via the terminal 31, the dimming / boosting / brightness control circuit 41 determines whether the LED group 42r, The current values to be supplied to 42g and 42b are determined. The dimming / boosting / brightness control circuit 41 further sends a command to the current supply circuit 40 so as to supply the current of the determined current value to the LED groups 42r, 42g and 42b of the respective colors.

  As is well known, an LED is a current-controlled device having a proportional relationship between drive current and light emission luminance (light emission intensity) in its rated range. When the current supply circuit 40 supplies a predetermined value of current to each LED group, each LED group emits light with a predetermined luminance. The dimming / boosting / brightness control circuit 41 ends the current supply to the LED groups 42r, 42g, and 42b when a signal instructing the end of light emission is transmitted from the CPU 101 of the camera body 10 via the terminal 31. A command is sent to the current supply circuit 40. In this way, the amount of light emitted from each color LED group is controlled.

  In the present embodiment, the LED groups 42r, 42g, and 42b of each color are caused to emit pulses in an exposure time range corresponding to the set shutter speed. FIG. 6 is a diagram illustrating a light emission pulse waveform of each LED group. 6 (1) shows the drive pulse waveform of the LED group 42r (1-3), FIG. 6 (2) shows the drive pulse waveform of the LED group 42g (1-3), and FIG. 6 (3) shows the LED group. 42b (1-3) represents the drive pulse waveform. The drive pulse width (that is, the light emission pulse width) of each LED group is set so that no drift occurs in the light emission wavelength and the light emission amount due to heat generation in the light emitting element. Here, drift refers to fluctuations in emission wavelength caused by heat generation, and reduction in emission luminance. The amount of light emitted by each LED group is indicated by the product of light emission luminance and light emission time. The dimming / boosting / brightness control circuit 41 determines a light emission amount (that is, a supply current to the LED group, a pulse width, and the number of pulses) for each color according to the color temperature correction amount. Send to.

  Data necessary for correcting the color temperature is stored in a non-volatile memory (not shown) in the dimming / boosting / luminance control circuit 41. For example, the color temperature correction amount is determined in advance based on the colorimetric data of the illumination light from the xenon discharge tube 32, and the data indicating the light emission ratio of each LED group (each color) for obtaining this color temperature correction amount is non-volatile. Stored in memory.

  Moreover, the relationship between the light emission brightness (namely, supply current) by LED group 42r (1-3), LED group 42g (1-3), LED group 42b (1-3), and light emission time (pulse width x number of pulses) is as follows. The actual measurement results are tabulated in advance and stored in the nonvolatile memory (not shown).

  Furthermore, a plurality of sets of irradiation patterns corresponding to a plurality of focal lengths of the photographing lens 20 with respect to the irradiation patterns by the LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3). Data is stored in the non-volatile memory. Even when the subject distance is the same, the shooting angle of view differs between a wide-angle lens with a short focal length and a telephoto lens with a long focal length. Therefore, the dimming / boosting / brightness control circuit 41 acquires the focal length as lens information from the camera body 10, reads the irradiation pattern data corresponding to the acquired focal length from the nonvolatile memory, and obtains this irradiation pattern. The LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3) are caused to emit light. Specifically, when only the light emitting elements near the center of the LED array are turned on, the irradiation range is narrowed, and when the light emitting elements of the entire LED array are turned on, the irradiation range is widened. By making the irradiation range variable, it is possible to prevent irradiation to a useless range.

  The dimming / boosting / brightness control circuit 41 refers to the LED groups 42r (1-3), the LED groups 42g (1-3), and the LED groups 42b () determined by referring to the data stored in the nonvolatile memory. 1-3) is adjusted according to the distance information (data indicating the distance to the main subject) acquired from the camera body 10.

  FIG. 7 is a diagram for explaining the irradiation pattern thus determined. In FIG. 7, the irradiation range 32A by the xenon discharge tube 32 is wider than the imaging range. The irradiation range 42A by the LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3) is made wider than the irradiation range 32A by the xenon discharge tube 32. In addition, each LED group 42r (1-3), LED group 42g (1-3), and LED group 42b (1-3) are comprised so that each may irradiate the common irradiation range 42A.

According to the embodiment described above, the following operational effects can be obtained.
(1) An LED group 42r (1-3) that emits red component light from the illuminant of the white light emitting unit of the illumination device 30 is constituted by a xenon discharge tube 32, and the illuminant of the color temperature correction light emitting unit is green component light. LED group 42g (1-3) emitting blue light and LED group 42b (1-3) emitting blue component light, respectively, and the color temperature of the illumination light from the xenon discharge tube 32 is corrected by the LED light. According to this method, since the color temperature can be continuously corrected by changing the emission ratio of each LED group (each color), illumination light corrected to an arbitrary color temperature can be obtained.

(2) The irradiation range 32A by the xenon discharge tube 32 is made wider than the imaging range, and the irradiation range 42A by the LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3) Including the irradiation range 32A by the xenon discharge tube 32, the irradiation range was made wider than 32A. Therefore, the luminance difference of the color temperature correction light generated between the central portion and the peripheral portion of the photographing range is suppressed to be smaller than the luminance difference of the color temperature correction light generated between the central portion and the peripheral portion of the irradiation range 42A. It is done. As a result, the color ratio of the red, green, and blue components and the light emission luminance can be controlled almost uniformly in the shooting range, and a uniform color temperature correction effect can be obtained over the entire shooting range. The uneven color of the illumination light afterwards can be suppressed. The color unevenness of the illumination light has a greater sense of incongruity compared to the brightness difference of the illumination light, so the illumination angle of view of the light emitter of the color temperature correction light emitter is wider than that of the emitter of the white light emitter. Doing has a big meaning. In particular, when the illumination field angle of illumination light is configured to be variable and the illumination field angle is set to be wide according to the focal length of the photographic lens 20, the illumination light is emitted at the center and the periphery of the illumination range. The effect is great because the difference in luminance is likely to occur.

(3) The LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3) can emit light continuously for a longer time than the xenon discharge tube 32. Therefore, even if the light emission luminance by the LED group is lower than the light emission luminance by the xenon discharge tube 32, the color temperature correction effect can be sufficiently obtained by making the light emission time of the LED group longer than the flash time of the xenon discharge tube 32. However, the light emission time (pulse width × number of pulses) of the LED group is not longer than the fully open time of the shutter.

  In the above description, the light emitter of the white light emitting unit is configured by the xenon discharge tube 32, but a white LED may be used instead of the xenon discharge tube 32.

  Although LED group 42r (1-3), LED group 42g (1-3), and LED group 42b (1-3) were made to emit light in a pulse, you may make it make it emit continuously instead of pulse light emission. In this case, it is important to take heat dissipation measures so that the light emitting elements constituting the LED group do not drift due to temperature rise.

  Configuration example in which the irradiation range 42A by the LED group 42r (1-3), the LED group 42g (1-3), and the LED group 42b (1-3) is variable according to lens information (focal length of the photographing lens 20). Explained. Instead of this, the irradiation range may be fixed so as to cover the photographing field angle of the photographing lens (wide-angle lens) having the shortest focal length. In this case, the color temperature correction light is always emitted to a wide irradiation angle of view regardless of whether the photographing lens is wide-angle or telephoto. The circuit configuration can be simplified by fixing the irradiation range.

  The example in which the color temperature correction light is composed of the light of the R color component, the G color component, and the B color component has been described, but it is not necessarily the light of the three color components. Alternatively, it may be composed of only monochromatic component light.

  The LED group is shown as an example of three LEDs (light emitting diodes) for each color. However, the number of light emitting elements is not limited to three as described above, and irradiation intensity and irradiation range can be four or twenty. It may be changed appropriately according to the situation.

  Moreover, although the example which mounts LED group in 1 horizontal row was shown, it may be 2 rows or 5 rows, and may change suitably according to irradiation intensity or irradiation range.

  You may comprise LED42 mounted on the board | substrate 43 by an organic EL element. High-intensity light can be obtained compared to LEDs.

  In the above description, the external illumination device 30 has been described as an example, but the illumination device may be built in the camera body.

  The camera body described above may be a digital camera or a silver salt camera.

  Correspondence between each component in the claims and each component in the best mode for carrying out the invention will be described. The first irradiation range corresponds to, for example, the irradiation range 32A. The illumination light emitting unit is configured by, for example, a xenon discharge tube 32 and a light emission control circuit 39. The color temperature correction light emitting unit includes, for example, an LED group 42r (1-3), an LED group 42g (1-3), an LED group 42b (1-3), and a current supply circuit 40. For example, the irradiation range 42A corresponds to the second irradiation range. The color temperature correction instruction corresponds to the light emission instruction by the CPU 101. The light emission control means is constituted by a dimming / boosting / luminance control circuit 41, for example. In addition, as long as the characteristic function of this invention is not impaired, each component is not limited to the said structure.

1 is an external view of a camera system equipped with a lighting device according to an embodiment of the present invention. It is a block diagram explaining the principal part structure of the camera system of FIG. It is a figure explaining the optical system of an illuminating device. It is an enlarged view of a board | substrate and LED. It is a detailed block block diagram of an illuminating device. (1) is a diagram showing the drive pulse waveform of the LED group 42r, (2) is a diagram showing the drive pulse waveform of the LED group 42g, and (3) is a diagram showing the drive pulse waveform of the LED group 42b. It is a figure explaining an irradiation pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Camera body 20 ... Shooting lens 30 ... Illuminating device 32 ... Xenon discharge tube 33 ... Main capacitor 34 ... Voltage detection circuit 35 ... Boosting circuit 39 ... Light emission control circuit 40 ... Current supply circuit 41 ... Dimming / boosting / luminance control circuit 42 (42r, 42g, 42b) ... LED
43 ... Board 101 ... CPU
L1, L2a, L2b, L3 ... Lens

Claims (7)

An illumination light emitting unit having a first irradiation range wider than at least the imaging range;
A color temperature-correcting light emitting unit including the first irradiation range and having a second irradiation range wider than the first irradiation range;
An illumination apparatus for photographing, comprising: a light emission control means for controlling light emission of the color temperature correction light emitting unit so as to correct a color temperature of illumination light by the illumination light emitting unit according to a color temperature correction instruction. . The illumination device for photographing according to claim 1,
The illuminating device for photographing, wherein the light emission control means changes the second irradiation range according to a focal length of a photographing lens. The illumination device for photographing according to claim 1,
The light emission control means fixes the second irradiation range to an irradiation range corresponding to a shooting range when using a wide-angle shooting lens. In the imaging | photography illumination device as described in any one of Claims 1-3,
The illuminating device for photographing, wherein the color temperature correction light emitting section includes an LED that emits at least a single color component light. In the imaging | photography illumination device as described in any one of Claims 1-3,
The illuminating device for photographing according to claim 1, wherein the color temperature correction light emitting unit includes a surface light emitting element that emits at least single color component light. In the imaging | photography illumination device as described in any one of Claims 1-3,
The illuminating device for photographing, wherein the color temperature correction light emitting unit includes an organic EL that emits at least single color component light.   A camera comprising the photographing illumination device according to any one of claims 1 to 6.

Images