JP2005352252A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the miniaturization and power saving of the device even if an auxiliary light source for photographing is built into a camera. <P>SOLUTION: A plurality of LED elements and a projection lens for projecting their respective radiation light are arranged on the front of the camera. When carrying out flash illumination, the individual LED elements are driven by time division with high luminance and pulse light emission is caused by taking a long light emission period. As a result, while the light emission loads of the individual LED elements are reduced, an exposure is assured at the cumulative light volume projected to a subject. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a camera having a light source for assisting photographing.

In recent years, for example, a camera with a built-in strobe is widely used in various cameras such as a single-lens reflex 35 mm camera, a compact camera, a camera with a built-in film, and a digital camera. In most cases, such a strobe lights a xenon flash lamp using high-pressure discharge at a high frequency. The emission wavelength band is generally white light.
For example, Patent Document 1 describes an electronic camera that includes a strobe and performs a photographing operation after a predetermined time from the strobe emission.
Patent Document 2 discloses a torch lamp in which a strobe of a camera is configured using a light emitting diode (hereinafter abbreviated as LED) as a light source. According to this configuration, the plurality of LED chips supported on the rotating drum are rotated at the focal position of the concave reflecting mirror that emits light to the object to be photographed, and LEDs that emit light with high brightness are sequentially switched and used. Yes.
JP 2000-341580 A (page 2-3, FIGS. 1 and 4) JP 2003-346503 A (page 10-11, FIGS. 5 and 6)

However, the above cameras have the following problems.
In the technique described in Patent Document 1, for example, a large-capacity capacitor is required to apply a high voltage to a strobe such as a xenon flash lamp. Therefore, since it is necessary to incorporate a large capacitor such as an aluminum electrolytic capacitor, there is a problem that the camera cannot be miniaturized. In addition, there is a problem that the light emission of the xenon flash lamp leads to an increase in power consumption. Especially in digital cameras, a lot of power is consumed by electrical systems that are not available in analog cameras, such as CCD drive units and color liquid crystal display units, so there is a strong demand for light-emitting sources with low power consumption in order to extend battery life. .
In the technique described in Patent Document 2, a plurality of LEDs are rotated to realize periodic light emission with high luminance. However, in order to perform sufficient dimming in a high-speed shutter speed region, the light must be lit in a short period. Therefore, it is necessary to rotate a large number of LEDs at a high speed. Therefore, there exists a problem that it is easy to enlarge. Further, even if the size can be reduced, there is a problem that the power consumption becomes large because the high-speed rotary motor is provided.
In addition, since the light emitting position of a device including a plurality of movable LEDs is fixed, high-intensity flash light is emitted from one place, so that the shadow edge of the subject appears sharply.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a camera that can achieve downsizing and power saving of the apparatus even if an auxiliary light source for photographing is incorporated. To do.

In order to solve the above-described problem, in the invention according to claim 1, in the camera, a light-emitting unit in which a plurality of solid-state light-emitting elements, each of which can be independently controlled to be lighted, are fixedly arranged, and the plurality of solid-states Projection optical elements that project the respective light emitted from the light emitting elements over a predetermined range, and each light emitting condition is set from the necessary exposure amount in order to cause the light emitting unit to emit light according to the necessary exposure amount. A lighting control means for sequentially lighting a plurality of solid state light emitting elements in a time-division manner is provided.
According to the present invention, a plurality of solid state light emitting elements are fixedly arranged in the light emitting section, and the lighting control means performs time division lighting under each light emission condition set from the required exposure amount, and projects the light of each solid state light emitting element. The image can be projected in a predetermined range by the optical element. Therefore, high-luminance illumination light can be emitted from the light emitting unit and projected onto a predetermined range to assist photographing. At that time, by reducing the light emission load per one solid-state light emitting element and lengthening the light emission period, a plurality of solid state light emitting elements are cumulatively illuminated within the exposure time, thereby illuminating the subject with the necessary exposure amount. Light can be formed. Therefore, it is possible to obtain a camera provided with an imaging auxiliary light source with low power consumption without using large components such as a capacitor for high-voltage discharge.

According to a second aspect of the present invention, in the camera according to the first aspect, a current value exceeding a rated current value of continuous light emission is set as a maximum current value when a light emission condition of an element to be lit among the plurality of solid state light emitting elements. It is set as the structure made into the pulse light emission to do.
According to the present invention, pulsed light emission is performed at a current value whose maximum current value exceeds the rated current value for continuous light emission, and thus high-luminance light emission can be realized. Then, by sufficiently shortening the pulse lighting time width of each solid state light emitting element, it is possible to emit light without affecting the element life.

According to a third aspect of the present invention, in the camera according to the first or second aspect, when the lighting control means turns on one of the plurality of solid state light emitting elements, the amount of light from a subject is detected and the lighting is performed. An automatic light control means for changing the light emission condition set in the control means is provided.
According to the present invention, the automatic light control means changes the light emission condition set in the lighting control means so that the light intensity from the subject can be detected and the light emission amount suitable for the imaging condition can be obtained by the automatic light control means. It can be performed.

According to a fourth aspect of the present invention, in the camera according to any one of the first to third aspects, the plurality of solid-state light emitting elements are configured by white LED elements having a wavelength characteristic of white light.
According to this invention, since the solid-state light emitting element has the wavelength characteristic of white light, for example, a white light source can be configured with a simple configuration without using a wavelength conversion filter or the like.

According to a fifth aspect of the present invention, in the camera according to any one of the first to third aspects, the plurality of solid state light emitting elements are composed of a plurality of LED elements having a plurality of types of wavelength characteristics, and the lighting control means. However, the plurality of LED elements are configured to be able to vary the cumulative wavelength characteristics of the light emitted within the exposure time by controlling the light emission conditions according to the respective wavelength characteristics.
According to the present invention, the lighting control means can emit light having a plurality of types of wavelength characteristics within the exposure time to vary the cumulative wavelength characteristics, so that color correction by photographing light can be performed. Therefore, for example, if a wavelength conversion filter is attached or a digital camera is used, an image whose color has been corrected can be easily captured without performing image processing after shooting.
The plurality of types of wavelength characteristics can be selected as appropriate according to the characteristics of the LED elements, but it is particularly preferable that the wavelength characteristics correspond to the three RGB primary colors. In this case, the variable range of the cumulative wavelength characteristic can be widened, and calculation processing for the variable is facilitated.

According to a sixth aspect of the present invention, in the camera according to any one of the first to fifth aspects, the lighting control unit is configured to switch the solid-state light emitting element before the start of exposure under pre-emission conditions different from the emission conditions during exposure. It is set as the structure provided with the pre light emission mode to light-emit.
According to the present invention, since the pre-emission mode is provided, the solid light-emitting element can be made to emit light according to the pre-emission condition before the start of exposure. Therefore, by appropriately setting the pre-emission condition, for example, red-eye prevention light, Light other than photographing light such as auxiliary light for autofocus can be generated to serve as these light sources.

  According to the camera of the present invention, a plurality of solid state light emitting elements fixedly arranged on the camera body are provided, and the subject can be cumulatively illuminated within the exposure time by sequentially lighting them in time division. Thus, it is possible to provide a camera with a low power consumption photographing auxiliary light source.

Hereinafter, details of embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.
A camera according to an embodiment of the present invention will be described.
FIG. 1 is an explanatory front view for explaining the appearance of a camera according to an embodiment of the present invention in a shootable state. FIG. 2 is an explanatory front view for explaining the appearance when the power is off. FIG. 3 is an explanatory view of the back surface of the camera according to the embodiment of the present invention. FIG. 4 is a functional block diagram for explaining a schematic configuration of a camera control system according to the embodiment of the present invention.

The digital camera 100 (camera) of the present embodiment includes a plurality of LED light emitting elements in the camera body in order to form a flash illumination light source for use as a photographing auxiliary light source in night photography, indoor photography, backlight compensation photography, and the like. While being built in, it is possible to achieve downsizing and power saving.
As shown in FIGS. 1 and 3, the camera body of the digital camera 100 is covered with a housing made up of a front cover 1 and a rear cover 13 that are substantially rectangular when viewed from the front.
In front view (see FIG. 1), the lens barrel 2, the flash light emitting unit 4 (light emitting unit), the finder opening 5A, the light control sensor 28, and the lens barrier 6 are provided on the front cover 1. .
Further, in the rear view (see FIG. 3), the finder eyepiece 5B, the liquid crystal display unit 11, the operation dial 8, and the selection operation unit 9 are provided on the rear cover 13.
An operation unit 7 is provided on a lateral side surface of the housing.

The lens barrel 2 includes an imaging lens 3 having a zoom function, and is provided at an intermediate portion in front view of the front cover 1 so as to be able to appear and retract with respect to the front cover 1 for zooming magnification.
The lens barrier 6 is provided to protect the imaging lens 3 at the end of photographing. The lens barrier 6 is provided on the front cover 1 in a strip shape in the short side direction of the front cover 1 as viewed from the front, and is also slidable in the longitudinal direction. Has been. Then, an open state that is retracted from the front side of the imaging lens 3 and arranged on one end side in the longitudinal direction of the front cover 1 and a closed state that covers and shields the front surface of the imaging lens 3 as shown in FIG. 2 are selected. And is lightly locked so that each state can be maintained.
An end portion 6a on the imaging lens 3 side of the lens barrier 6 has a shape that extends in the short direction on the front cover 1 and is locked along a stepped locking portion 1a. The part 6a and the locking part 1a are configured to meet with no gap.
A projection 6 b is provided at the end of the lens barrier 6 opposite to the imaging lens 3. In the open state, a front grip portion for holding the digital camera 100 is formed.
The sliding operation of the front cover 1 is interlocked with a power switch (not shown), and the open / close state of the lens barrier 6 also serves as a switch mechanism corresponding to turning on / off the main power supply of the digital camera 100.

The finder opening 5A and the finder eyepiece 5B are provided with a finder optical system (not shown) between them, and constitute an optical finder of the digital camera 100.
The liquid crystal display unit 11 displays a captured subject image, and displays an operation menu screen for shooting conditions and various settings.
The operation unit 7 includes a release button 7a and a zoom lever 7b, which can perform shutter release and zoom operations, respectively.
When the release button 7a is half-pressed, auto focus and automatic exposure are set, and when fully pressed, the shutter release is performed.

The operation dial 8 and the selection operation unit 9 are provided between the liquid crystal display unit 11 and the grip unit 10 in which a concavo-convex shape for gripping is formed at a position corresponding to the back side of the projection 6b in the opened state of the lens barrier 6. It is disposed on the rear cover 13.
The operation dial 8 is an operation input mechanism for selecting a shooting mode or the like by dial operation.
The selection operation unit 9 is a type of operation unit that selects an operation menu displayed on the liquid crystal display unit 11 with the selection button 9a and confirms the selection with the determination button 9b.

As schematically shown in FIG. 4, the flash light emitting unit 4 includes a projection lens 40 (projection optical element), n (n ≧ 2) LED elements L ₁ ,..., L _n (fixed light emitting elements), As shown in FIG. 1, in the open state of the lens barrier 6, the lens cover 6 is disposed so as to extend linearly in the longitudinal direction of the front cover 1 between the end portion 6 a and the locking portion 1 a. In the direction, it is a photographing auxiliary light source disposed between the finder opening 5A and the lens barrel 2.
Therefore, when the lens barrier 6 is closed, the lens barrier 6 is covered and protected, and when the lens barrier 6 is open, the operator's hand is held when the operator holds and holds the protrusion 6b and the grip 10. It is not to touch.

  The light control sensor 28 is a light receiving sensor that monitors the return light from the subject when the flash light emitting unit 4 emits light in order to adjust the light emission amount of the flash light emitting unit 4 as necessary.

Here, the configuration of the flash light emitting unit 4 will be described in more detail.
FIG. 5A is a cross-sectional explanatory diagram in a cross section including an optical axis for explaining the configuration and schematic optical path of the flash light emitting unit. FIGS. 5B and 5C are cross-sectional explanatory views for describing another example of the flash light emitting unit.
In the present embodiment, as shown in FIG. 5A, the LED elements L _{1 to} L _n of the flash light emitting unit 4 are arranged in a line on the substrate 4a so that the respective light emitting points form a pitch d. Yes. In the present embodiment, the LED elements L _{1 to} L _n are white LED elements that can obtain the wavelength characteristics of white light by themselves. The number of LED elements is, for example, n = 12.
In addition, this number and arrangement | sequence form are examples, Comprising: It is not limited to this. For example, they can be arranged in a plurality of rows or densely arranged in a circular or rectangular region.

The projection lens 40 is a microlens array that is provided in the vicinity of the light emitting surfaces of the LED elements L _{1 to} L _n and collects light emitted from each of the LED elements L _{1 to} L _n at a predetermined spread angle. For example, a plastic molded lens can be used as the projection lens 40.
The light emitted from each of the LED elements L _{1 to} L _n is projected so that light beams whose optical axes are shifted by the pitch d are overlapped, and, for example, on a subject separated by a distance D as shown in FIG. , And overlap each other by a distance d sequentially like widths W ₁ ,..., W _n . In FIG. 5A, reference numeral 200 denotes a central optical axis of the flash light emitting unit 4.
Since the distance d is much smaller than the size of a general subject, the width W (predetermined range) where they overlap can substantially cover the entire subject.

The projection optical element of the flash light emitting unit 4 is not limited to the projection lens 40 described above. For example, in order to obtain a more compact configuration, a projection lens 41 (see FIG. 5B) formed in a flat plate shape using a Fresnel lens or the like can be employed.
Moreover, in order to save the time and effort of an assembly, the element integrated lens 42 (refer FIG.5 (c)) provided for every chip | tip of each LED element is employable.
Further, if necessary, an aperture or a filter may be provided between the LED element and the projection optical element.

Next, a schematic configuration of a control system of the digital camera 100 for lighting the flash light emitting unit 4 will be described.
As shown in FIG. 4, the schematic configuration of the control system of the digital camera 100 includes an image processing unit 22, a recording unit 23, a main control unit 24, a timing generation unit 25, a lighting control unit 26 (lighting control means), and light control. It consists of the control part 27 (automatic light control means).

The A / D conversion unit 21 is connected to an image sensor 20 that receives an image of a subject imaged by the imaging lens 3, and a digital image signal corresponding to luminance information is stored charge transferred from the image sensor 20 for each pixel. It is to convert to.
As the imaging element 20, a two-dimensional image sensor made of, for example, a CCD or a CMOS is used.
The image processing unit 22 is connected to the A / D conversion unit 21 and performs appropriate image processing on the digitized image signal. For example, processing such as shading correction and noise removal processing is performed.
The recording unit 23 is connected to the image processing unit 22 and records the image signal after the image processing on a storage medium.

Lighting control unit 26 is connected to the LED elements _L 1 ~L _n, is the LED elements _L 1 ~L _n one which selectively flashing at a predetermined timing.
The LED elements L _{1 to} L _n are controlled in light emission amount by controlling the drive current.
FIG. 6 is a schematic graph for explaining the current-luminescence characteristics of the LED element. The horizontal axis in FIG. 6 indicates the current for driving the LED element, and the vertical axis indicates the light emission amount.
LED elements, as shown by the curve 201 in FIG. 6, in the rated current I _r is to change the current and light emission amount linearly, the current is substantially linear monotonic function be greater than the rated current I _r .
In general, in the following continuous light emission can be rated current I _r, the light emission amount but is used to be equal to or less than P _r, as the thermal load is reduced, by driving a sufficiently small pulse width in a predetermined cycle or It is known that even if current I _t (where I _r <I _t ) is passed and light is emitted with a light emission amount P _t (where P _t > P _r ), the lifetime is not adversely affected.
Therefore, for example, may be a maximum current value of about 6 times the rated current I _r. In an LED element that can obtain a luminous intensity of 2000 mcd when a forward current of 50 mA is passed, an illuminance of 200 lx can be obtained when the subject is illuminated from a distance of 10 cm. If pulse width driving with a maximum current value of 300 mA is performed using this LED element, the illuminance will be about 1200 lx, which is about 6 times.

Therefore, as illustrated in FIG. 7, the lighting control unit 26 drives the LED elements L _{1 to} L _n with a pulse width t _{L so} that the maximum light emission amounts of the LED elements L _{1 to} L _n are P _t1 to P _t respectively. _Ptn , and the LED elements L _{1 to} L _n can be sequentially time-division driven. That is, the lighting control unit 26 sequentially supplies currents I _{t1 to Itn} (where I _r <I _ti , i = 1,..., N) to the LED elements L _{1 to} L _n every time t _L. Is.
Such time-division driving is repeated a plurality of times as necessary depending on the light emission duration. In that case, the light emission period T of one LED element is T = t _L · n. Emitting period T is longer than the allowable emission period determined according to the value of P _t.
The currents I _{t1 to It tn} may be different values or the same value. These current values are initialized by the main control unit 24 described later as the light emission conditions of the flash light emitting unit 4 together with the time t _L and the number of times of light emission.

The dimming control unit 27 is for changing the accumulated light emission amount of the flash light emitting unit 4 based on the signal of the light control sensor 28 during photographing for causing the flash light emitting unit 4 to emit light. To change the accumulated light emission amount, for example, the initial light emission conditions such as the number of light emission times of the LED elements L _{1 to} L _{n and} the light emission amount (drive current) once are reset, and the light emission conditions thereafter are changed. Can be done.
The timing generation unit 25 is connected to the main control unit 24 and controls the data read timing of the image sensor 20 and the operation timing of the lighting control unit 26 based on the shutter release timing. On the basis of the reference clock, a carrier clock for the image sensor 20 and a switching clock for switching the LED elements L _{1 to} L _n at a period of time t _L are supplied.

  The main control unit 24 is connected to at least the image processing unit 22, the recording unit 23, the timing generation unit 25, the lighting control unit 26, and the dimming control unit 27, and is also connected to other control blocks (not shown) This is for performing overall control of the camera 100.

Next, with regard to the operation at the time of shooting of the digital camera 100 of the present embodiment, description of well-known operations will be omitted, and the operation of flash illumination will be mainly described.
FIG. 8 is a flowchart for explaining the operation of the camera according to the embodiment of the present invention. FIG. 9 is a timing chart for explaining the operation of the camera according to the embodiment of the present invention. Note that the timing chart of FIG. 9 is schematically drawn, the length is exaggerated, and the ratio is not accurate.

In order to perform shooting using auxiliary illumination with the digital camera 100, a predetermined flash function mode is selected in advance with the operation dial 8 so that the flash function is enabled during shooting. If necessary, a red-eye reduction light emission mode (hereinafter abbreviated as red-eye mode) that reduces the so-called red-eye phenomenon is selected.
Then, a setting mode is selected in which the exposure condition relating to the combination of the aperture and the shutter speed is set automatically or manually. Hereinafter, a case where the exposure conditions are automatically set as appropriate will be described.
In the following description, the control is executed by the main control unit 24 unless otherwise specified. Also, the times t ₁ to t ₆ , t _a , t _b , t _c , t _d , and t _e quoted for convenience of reference below are times that pass in this order as shown in FIG. is there.

As shown in FIG. 8, when the release button 7a is half-pressed in step S1 (time t ₁ ), the main control unit 24 detects this, and step S2 is executed.
In step S2, an AE operation is executed, and an exposure condition suitable for the shooting scene is set according to a preset shooting mode. At this time, if it is determined that the light amount is insufficient, the light emission condition of the flash light emitting unit 4 for compensating the insufficient light amount is set.
First, the flashable time _TL of the flash light emitting unit 4 is calculated from the shutter speed of the exposure condition. For example, as shown in FIG. 9, when the shutter is opened at time _t 3 ~t _e, flash shooting mode is the time _t 4 ~t _d in the opening _time, T _{L =} t d -t ₄
Here, _assuming that the insufficient light quantity is Q, and for the sake of simplicity, _{assuming that} the light emission amounts of the LED elements L _{1 to} L _n are the same P _t , K is converted into an integer from K = Q / (P _t · t _L ). Thus, the required number of times of light emission k is obtained.
At this time, if T _L <k · t _L , since the required amount of light emission cannot be realized within the light emission possible time, the light emission amount P _t is increased to reduce the number of light emission k, and the light emission possible time T _The light emission ends in _L. At that time, as the LED elements is not degraded, the light-emitting period of each LED element is sufficiently longer set according to the light emission amount P _t. If a sufficient light emission cycle cannot be obtained, a shortage of exposure is notified.

Next, in step S3, focus adjustment is performed. Since the focus adjustment may be performed by any known method, detailed description thereof is omitted. In step S4, it is determined whether or not the subject is in focus, and loops until the subject is in focus and step S3 is executed.
When the focusing is completed (time t ₂ ), the focus is locked, the completion of focusing is notified so that the photographer can understand, and step S5 is executed. Photographer, after knowing the in-focus end, it is assumed that all press the shutter release button 7a to time t _3.
Needless to say, steps S3 and S4 may be executed in parallel with the control operation of the main control unit 24 by providing an autofocus control unit, for example.

In step S5, it is determined whether the red-eye mode is set. If the red-eye mode is set, step S6 is executed.
If the red-eye mode is not set, step S7 is executed.

In step S6, a control signal for executing the red-eye mode is sent to the lighting control unit 26, and pre-light emission is performed based on light emission for pre-light emission in the red-eye mode.
For pre-emission to reduce the red eye, there are various methods, in this embodiment, between the time t ₂ ~t _3, shall pulse light emission of the LED element L ₁ with a current I _t. If the amount of light is insufficient with only one LED element, a plurality of elements may be pulsed at the same time or with a short period.

When the release button 7a is fully depressed at time t _3, step S7 is executed.
In step S7, imaging is started under the exposure conditions set in step S2. That is, if there is an LED element that is lit in the red-eye mode, it is turned off and the shutter is opened. In addition, a timing signal for operating the image sensor 20 and an operation clock are supplied from the timing generation unit 25, and charge accumulation corresponding to the amount of received light is started in each pixel.
Then steps performed S8~S13 is until time t ₄ ~t _d, in order to compensate for the lack exposure, flash light emitting section 4 is the description of the process of light emission. Control of this process is performed in cooperation with the timing generation unit 25, the lighting control unit 26, and the dimming control unit 27 in accordance with a control signal from the main control unit 24.

In step S8, the lighting control unit 26 initializes a counter i that counts the number of times of light emission based on the light emission conditions.
In step S9, the counter i is updated. Then, a timing signal for emitting light at time t4 and a clock signal for performing pulse emission based on the emission conditions are supplied from the timing generation unit 25.
In step S <b> 10, the lighting control unit 26 emits the i-th LED light emitting element.
For example, as shown in FIG. 9, the case of i = 1, LED element _{L 2} is pulse lighting at time _{t 4.}

In step S11, the light adjustment control unit 27 detects the amount of light received by the light adjustment sensor 28, and determines whether or not an appropriate exposure amount can be obtained by the end of exposure under the current light emission conditions. If it is determined that an appropriate exposure amount cannot be obtained, step S12 is executed to correct the light emission condition. For example, the light emission amount after the next time is increased or decreased.
If it is determined that an appropriate exposure amount can be obtained, step S13 is executed.
In step S13, the lighting control unit 26 determines whether or not the number of times of light emission has reached a predetermined number of times of light emission k.
If i <k, step S9 is executed and steps S9 to S13 are repeated.
If i = k, step S14 is executed.

In this way, the LED elements L ₃ , L ₄ ,.
Then, LED device _{L 1} is round is lit at time _{t b,} 2 round lighting is started at time _{t c.} The total k times in pulse lighting, light emission is terminated at time t _d. During this time, an appropriate exposure amount that compensates for the underexposure amount as a whole is accumulated and irradiated by appropriately executing step S12.

In step S14, the control signal supplied by the timing generator 25 to close the shutter at time t _e. Then, the electric charge accumulated so far in each pixel is conveyed to the image sensor 20 and sent to the A / D converter 21.
In step S <b> 15, the signal sent to the A / D converter 21 is converted into a digital image signal and sent to the image processor 22.
In step S <b> 16, the image processing unit 22 performs appropriate image processing, and sends the processed image signal to the recording unit 23.
In step S <b> 17, the image signal is stored in the recording unit 23.
Thus, one shooting operation is completed.

As described above, according to the camera of the present embodiment, it is possible to secure the amount of illumination light without affecting the lifetime of the solid state light emitting device by accumulating the pulse light emission of the plurality of solid state light emitting devices driven in a time division manner. it can.
In addition, since a solid-state light emitting element is used, an apparatus with low power consumption can be obtained, and there is an advantage that variable light amount control and dimming control can be easily performed by current driving.
In addition, compared with a conventional method using a xenon flash lamp, a member such as a large aluminum electrolytic capacitor is not required, so that it can be made relatively small.

Further, since a plurality of solid state light emitting elements are fixedly arranged as the light emitting part and the projection optical element is arranged on the front surface of each of them, a simple configuration can be achieved without having a movable part.
At this time, in the present embodiment, since the solid light emitting elements are arranged in a line, the light emission position is shifted in the arrangement direction. As a result, the illumination angle with respect to the subject changes, and the shadow edge caused by the flash illumination can be blurred. There is.

Next, a first modification of the present embodiment will be described.
FIG. 10 is an explanatory front view for explaining a first modification of the embodiment of the present invention.
A digital camera 101 (camera) according to this modification includes a flash light emitting unit 50 (light emitting unit) instead of the flash light emitting unit 4 of the digital camera 100. Hereinafter, a description will be given focusing on differences from the above embodiment.
The flash light emitting unit 50 is configured by arranging a plurality of projection optical elements such as the LED elements L _{1 to} L _n and the projection lens 40 provided on the respective front surfaces in an annular shape so as to surround the outer periphery of the lens barrel 2.
With such a configuration, a ring strobe can be formed, and since each light emission position is equidistant from the optical axis, a well-balanced auxiliary illumination light that covers a predetermined circular range can be obtained.
Further, since there is no specific directionality in the illumination angle shift with respect to the subject, there is an advantage that the shadow edge caused by the flash illumination can be evenly blurred in any direction for any subject.
Further, since the flash light emitting unit 50 is provided in the vicinity of the lens barrel 2, the flash light emitting unit 50 is arranged so as not to be hidden by the photographer's hand no matter how it is held.
Note that when the lens barrel 2 has a large amount of protrusion and depression, the flash light emitting unit 50 is appropriately spaced in the radial direction of the lens barrel 2 so that illumination light is not emitted by the lens barrel 2. Alternatively, the flash light emitting unit 50 may be provided on the lens barrel 2 so as to appear and disappear together.

Next, a second modification of the present embodiment will be described.
In this modification, the LED elements L _{1 to} L _n are replaced with white LED elements, and a plurality of types of LED elements having different wavelength characteristics are provided.
For example, the LED elements L _{1 to} L _n have a configuration in which the same number of three types of LED elements each having the wavelength characteristics of the three primary colors R, G, and B are arranged.
According to such a configuration, by changing the ratio of the light emission amounts of R, G, and B, the cumulative wavelength characteristic of the light irradiated to the image sensor 20 can be appropriately changed to the wavelength characteristic of the color. .
As a result, the color correction can be performed by changing the wavelength characteristic of the photographing light without attaching the wavelength conversion filter to the imaging lens 3.
If each of R, G, and B has the same light emission amount, auxiliary illumination of white light can be obtained, but the wavelength approximated to sunlight, bulb light, fluorescent light, etc. by slightly changing the light emission amount ratio. Therefore, it is possible to easily obtain auxiliary illumination suitable for various shooting scenes.

  In the above description, the time-division driving of a plurality of solid state light emitting elements has been described as an example in which each solid state light emitting element is driven one by one. In some cases, a part of a plurality of solid state light emitting elements may be combined, and the combination may be used as a unit to drive the light by time division. In this case, there is an advantage that it is easy to cope with a higher shutter speed.

  In the above description, the time-division driving of the plurality of solid state light emitting elements has been described as an example in which the driving of each solid state light emitting element is a time axis, is continuous without a gap, and does not overlap. If the necessary exposure amount is sufficient, the light emission timings of the respective solid state light emitting elements may be driven so as to partially overlap each other or be skipped. That is, the lighting duty may be variable as the light emission condition set in the lighting control means.

  In the above description, in the pre-flash mode, an example of performing pre-flash for reducing red-eye has been described. However, if the pre-flash mode emits light under pre-flash conditions that are different from the flash conditions at the time of shooting, It is not limited to mitigation. Conventionally, in the present invention, the light emission function before photographing using LED light is also used as a solid light emitting element used for auxiliary illumination, and the number of parts can be reduced. For example, a pre-emission mode that emits autofocus auxiliary light may be provided.

  In the above description, the example in which the light emitting unit is built in the camera has been described. For example, the light emitting unit is detachably provided in the camera, or the light emitting unit is unitized and electrically connected with a connection cable at the time of shooting. It may be possible to do so.

  Further, in the above description, the example in which the optical axes of the solid light emitting elements are substantially parallel has been described. However, if the light of each solid light emitting element is projected onto a predetermined range covering the subject, the directions of the respective optical axes are different. May be.

In the above description, the example of a digital camera has been described as the camera. However, the present invention can also be suitably applied to an analog camera. For example, the present invention can be applied to all types of cameras such as a single-lens reflex 35 mm camera, a compact camera, and a camera with a built-in film.
In the case of a digital camera, the present invention can be similarly applied to an electronic shutter and a mechanical shutter.

It is front explanatory drawing for demonstrating the external appearance of the imaging | photography possible state of the camera which concerns on embodiment of this invention. It is front explanatory drawing for demonstrating the external appearance similarly at the time of power-off. It is back surface explanatory drawing of the camera which concerns on embodiment of this invention. FIG. 4 is a functional block diagram for explaining a schematic configuration of a camera control system according to the embodiment of the present invention. It is a functional block diagram for demonstrating schematic structure of the control system of the camera which concerns on embodiment of this invention. It is sectional explanatory drawing in the cross section containing the optical axis for demonstrating the structure and schematic optical path of a flash light emission part. It is a typical graph for demonstrating the electric current-light emission characteristic of an LED element. It is a typical timing chart for demonstrating the lighting drive operation | movement of the solid light emitting element by the lighting control means which concerns on embodiment of this invention. It is a flowchart for demonstrating operation | movement of the camera which concerns on embodiment of this invention. It is a timing chart for demonstrating operation | movement of the camera which concerns on embodiment of this invention. It is front explanatory drawing for demonstrating the 1st modification of embodiment of this invention.

Explanation of symbols

3 Imaging lens 4, 50 Flash light emitting part (light emitting part)
7a Release button 8 Operation dial 9 Selection operation unit 20 Image sensor 24 Main control unit 26 Lighting control unit (lighting control means)
27 Light control unit (automatic light control means)
L ₁ , L ₂ ,..., L _n LED element (solid state light emitting element)
40, 41 Projection lens (projection optical element)
42 Element-integrated lens (projection optical element)
100, 101 Digital camera (camera)

Claims (6)

A light-emitting unit in which a plurality of solid-state light-emitting elements, each of which can be controlled independently, are fixedly arranged;
A projection optical element that projects each light emitted from the plurality of solid state light emitting elements in a predetermined range;
In order to cause the light emitting unit to emit light in accordance with the required exposure amount, a lighting control unit that sequentially time-division-lights the plurality of solid state light emitting elements in which each light emission condition is set from the required exposure amount is provided. camera.   2. The camera according to claim 1, wherein a light emission condition of an element to be lit among the plurality of solid state light emitting elements is pulsed light emission having a current value exceeding a rated current value of continuous light emission as a maximum current value. .   An automatic dimming unit is provided that detects the amount of light from a subject when any one of the plurality of solid state light emitting elements is turned on by the lighting control unit, and changes the light emission condition set in the lighting control unit. The camera according to claim 1 or 2.   The camera according to any one of claims 1 to 3, wherein the plurality of solid-state light emitting elements are white LED elements having wavelength characteristics of white light. The plurality of solid state light emitting elements are composed of a plurality of LED elements having wavelength characteristics divided into a plurality of types,
The lighting control unit can vary the cumulative wavelength characteristics of light emitted within an exposure time by controlling the light emission conditions of the plurality of LED elements according to the wavelength characteristics of each of the plurality of LED elements. The camera according to claim 1.   The said lighting control means is provided with the pre light emission mode which makes the said solid light emitting element light-emit before the exposure start on the pre light emission conditions different from the light emission conditions at the time of exposure. camera.

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