JPH05204022A - Flash illumination device - Google Patents

Abstract

PURPOSE:To provide a flash illumination device which can adjust projected light quantity every plural areas of a field without complicating the constitution of an electric circuit so much. CONSTITUTION:A low voltage power source 11 which generates a low voltage, a boosting circuit 12 which boosts the low voltage impressed from the power source 11 to the high voltage, a first charge accumulation circuit 13 which accumulates electric energy generated by the boosting circuit 12 and a light emission part 14 which emits light by the electric energy accumulated in the accumulation circuit 13 are provided. Besides, a light quantity adjustment means 16 is disposed in an optical path where a flash radiated outward from the light emission part 14 is passed. Then, the electric energy for controlling the transmitted light quantity of the adjustment means 16 is accumulated in a second charge accumulation circuit 15 by the boosting circuit 12 which generates the electric energy for flash illumination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a light quantity adjusting section in the passage of a flash light projected outward from a light emitting section, and controls the light distribution distribution at the time of flash light emission in accordance with the spatial distribution state of a subject, for example. The present invention relates to a flash lighting device that can perform

[0002]

2. Description of the Related Art The present applicant has previously filed Japanese Patent Application No. 3-16014.
No. 1 specification has proposed a novel flash lighting device that controls the light distribution according to the spatial distribution of the subject. For example, in flash photography of three subjects with different distances as shown in FIG. 8, if the subject is illuminated with uniform irradiation light so that the person is photographed with an appropriate exposure, the subject in front of the person is exposed. Is over, and the subject behind is underexposed.

Therefore, in the above novel flash lighting device, a light quantity control element such as PLZT (light projecting ceramic) or liquid crystal is arranged in the passage of the flash light projected from the light emitting portion.
The irradiation light amount of each area is adjusted so that a plurality of subjects at different distances are uniformly exposed. Specifically, as shown in FIG. 8, the object field is divided into three regions L, C, and R, and the light amount control element is divided into three regions so as to individually adjust the projected light in each of the three regions. And the amount of light passing through each area is controlled according to the distance to the subject existing in each area.

By the way, a well-known PL as a light quantity control element
When ZT is used, the PLZT bulk is sandwiched by transparent counter electrodes, and a polarizing plate is placed on one of the electrodes and an analyzer plate is placed on the other electrode so that the polarizing axes of the polarizing plate and the analyzer plate coincide with each other. When a predetermined voltage is applied between the opposing electrodes, PLZ
The incident light of T bulk is emitted with its polarization axis rotated by 90 degrees. Therefore, when no voltage is applied, the light transmittance is almost 100%, and when a voltage is applied, the light transmittance is almost zero%. Therefore, in the case of FIG. 8, for example, the light amount control element is also divided into three regions corresponding to the three divisions defined by the dotted line, and the amount of light reflected from the subject existing in the three regions is measured to obtain a predetermined photometric value. When the value becomes a value, a voltage is applied to the PLZT bulk in the region to make the light transmittance almost zero, and the light distribution of the object field is adjusted. By doing so, the amount of light passing through the region L <the amount of light passing through the region C <the amount of light passing through the region R.

[0005]

However, the PLZ
The voltage applied to the T-bulk is required to be a voltage (several tens to several hundreds of volts) higher than several volts to several tens of volts which is usually used as a power source for a camera. Therefore, the booster circuit is indispensable like the flash device, and tends to be more complicated than the circuit configuration of the conventional flash device.

An object of the present invention is to provide a flashlight illuminating device capable of adjusting the amount of projected light for each of a plurality of regions of an object scene without making the structure of an electric circuit so complicated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIG. 1 showing an embodiment. In the present invention, a low voltage power source 11 for generating a low voltage and a low voltage power source 11 for applying the voltage are applied. A booster circuit 12 that boosts a low voltage to a high voltage, a first charge storage circuit 13 that stores the electrical energy generated by the booster circuit 12, and an electrical energy stored in the first charge storage circuit 13 The present invention is applied to a flash lighting device including a light emitting unit 14 that emits light. And the booster circuit 1
The second charge storage circuit 15 that stores the electric energy generated in 2 and the second charge storage circuit 15 that is arranged in the passage optical path of the flash light projected outward from the light emitting unit 14 and is applied from the second charge storage circuit 15. The above-described object is achieved by including the light amount adjusting means 16 that adjusts the passing light amount according to a high voltage.

[0008]

The high voltage output from the booster circuit 12 accumulates electric energy for controlling the light transmittance of the first charge accumulation circuit 13 for accumulating the emission energy of the light emitting section 14 and the light quantity control element 16. The second charge storage circuit 15 is charged respectively. Therefore, the booster circuit 12 can be used.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a control block diagram of a camera equipped with a flash lighting device, 10 is a flash lighting device, and 30 is a camera on which the flash lighting device is mounted or connected. The flash lighting device 10 includes a low-voltage power supply 11 that generates a low voltage, a booster circuit 12 that boosts a low voltage applied from the low-voltage power supply 11 to a high voltage, and an electric energy generated by the booster circuit 12. A first charge storage circuit 13 that stores the light and a light emitting unit 14 that emits light by the electric energy stored in the first charge storage circuit 13 are provided. In addition, the booster circuit 12
The second charge storage circuit 15 for storing the electric energy generated in step S1, and the high charge applied from the second charge storage circuit 15 are arranged in the passage optical path of the flash light projected outward from the light emitting section 14. A light distribution control element 16 for adjusting the amount of light passing therethrough according to a voltage, and a passage control circuit 1 for the light distribution control element 16.
7, a flash control circuit 18 of the light emitting unit 14, and a photometric circuit 19 for receiving and measuring the reflected light from the subject. The flash control circuit 18 causes the light emitting unit 14 to emit light in response to a flash start command from the CPU 31 on the camera side.

FIG. 2 shows the details of each component of FIG. 1. The low-voltage power supply 11 is composed of a DC power supply such as a battery, and when the switch 10S of the flash lighting device 10 is closed, power is supplied to the booster circuit 12 and the like. Is configured. As is well known, the booster circuit 12 includes a transistor 12a and a resistor 1
2b, a capacitor 12c, an oscillating transformer 12d, etc., and boosts the low voltage of the battery 11 to several tens to several hundreds of volts and outputs it. First charge storage circuit 13
Is a diode 13a that rectifies the high voltage boosted by the booster circuit 12, a first capacitor 13b that charges the rectified high voltage, and a neon light that lights up when the charging potential of the first capacitor 13b becomes a predetermined value or more. It is composed of a tube 13c. The second charge storage circuit 15 is provided in parallel with the first charge storage circuit 13, and has a diode 15a that rectifies the high voltage boosted by the booster circuit 12 and a second capacitor that charges the rectified high voltage. 15b and.

As is well known, the flash control circuit 18 has a resistor 1
8a, trigger capacitor 18b, and trigger transformer 1
8c and a trigger switch 18d that is closed by a light emission start signal from the camera side.
When d is closed, the trigger capacitor 18b is discharged and a high voltage is generated on the secondary side of the trigger transformer 18c.
The flash tube 141 of is triggered.

FIG. 3 is a detailed view showing the inside of the light emitting portion 14 of the flash lighting device 10. The light emitting unit 14 is a flash tube 14
1, the reflection shade 142, and the light distribution lens 143, and the light distribution control device 16 is provided in the optical path of the flash light reflected by the reflection shade 142 and projected to the outside. In addition, the light emitting unit 14 has a photometric element 191 divided into nine as described later.
Further, a lens 192 for making the reflected light of the subject incident on the photometric element 191 is provided.

The light distribution control element 16 is made of translucent ceramic (PLZT) or liquid crystal, and in this example, as shown in FIG. 3, the light distribution distribution is made to correspond to each region of the 9-divided field. The control element 16 is divided into 9 areas 1. The areas 1 to 9 substantially correspond to the nine divided areas of the photometric element 191. Reference numerals 16a to 1 denote the light distribution control elements of the respective regions 1 to 9.
6i, the photometric elements are denoted by reference numerals 191a to 191i. FIG. 4 shows the principle structure of a translucent ceramic provided corresponding to each of the nine regions. As PLZT
A bulk 161 of PbLa (ZrTi) O ₃ is used, and the bulk 1
Transparent electrodes 162 and 163 are provided on both upper and lower surfaces of 61, and a polarizing plate 164 and an analysis plate 165 are provided to face the transparent electrodes 162 and 163, respectively. Figure 4
As shown in (a), the polarization axes PD1 of the polarizing plate 164 and the analysis plate 165 are aligned.

In FIG. 1, the light transmittance of the light distribution control element 16 is controlled by the passage control circuit 17. As shown in FIG. 4, the passage control circuit 17 is composed of a constant voltage circuit 171 and a switch 172. The constant voltage circuit 171 and the switch 172 are provided in series between the transparent electrodes 162 and 163 so that the photometry result for each area is predetermined. When the value is reached, the switch 172 is closed and a constant voltage is applied to the PLZT 161. PLZT16
When a high voltage is applied to 1, the refractive index changes, which changes the optical phase difference of the incident light and polarizes the output light. Therefore, switch 172 closes and PLZT16
1 when a constant voltage is applied, the incident light of the PLZT 161 with the polarization axis of pd1 is directed in the direction pd2 shown in FIG.
When the light is polarized and emitted,
Since the polarization direction of the light emitted from the LZT 161 is deviated by 90 degrees, the light transmittance becomes almost zero. When a voltage is not applied to the PLZT 161, the emitted light of the PLZT 161 does not cause an optical phase difference with respect to the incident light, so that FIG.
The polarization axes of the incident light and the emitted light are both pd
The light transmittance is about 100%. Further, the light transmittance can be appropriately adjusted by adjusting the applied voltage, but in the present embodiment, whether or not a predetermined voltage is applied, that is, the light transmittance is set to 100% or substantially zero. Control only that.

As described above, the constant voltage circuit 171 and the switch 172 form a part of the passage control circuit 17.
That is, as shown in FIG. 2, the passage control circuit 17 controls the light distribution control elements 16a in each of the above-mentioned nine regions.
16i corresponding to the constant voltage circuit 17 provided
1a to 171i and the constant voltage circuits 171a to 171i, which are open until a high level signal is output from each terminal C of the photometric circuit 19 so that a constant voltage is not applied to the PLZT. A thyristor 172a that is closed when a level signal is output and applies a constant voltage
~ 172i. Further, the passage control circuit 17 has a switching circuit 173 that resets the thyristors 172a to 172i.

The constant voltage circuits 171a to 171i connected to the respective light distribution control elements 16a to 16i are constructed, for example, as shown in FIG. In FIG. 5, the resistor 1
71a and the Zener diode 171b are arranged in series between both terminals of the second capacitor 15b, and the resistor 171c is connected in parallel with the Zener diode 171b. With such a circuit configuration, the applied voltage does not change due to the voltage change of the second capacitor 15b, and the light transmittance can be adjusted stably.

In the switch circuit 173, as shown in FIG. 6A, the drains are connected to the cathodes of the thyristors 172a to 172i, and the source is connected to the ground line via the resistor 173d, and the first FET 173a. This junction type FE depends on the voltage between both terminals of the capacitor 13b.
Resistors 173b and 17 for controlling the gate voltage of T173a
3c is provided. Since the voltage between both terminals of the first capacitor 13b is high at the start of light emission of the flash tube 141, the junction type FET1
73a is turned on, light emission progresses, and the first capacitor 13
The voltage between both terminals of b decreases. Then, the voltage applied to the resistor 173c also decreases, and when the voltage applied to the gate of the junction FET 173a decreases to the threshold level, the junction FE
T173a turns off. When the junction type FET 173a is turned off, all nine thyristors 172a to 172i are reset.

Further, in FIG. 2, the photometric circuit 19 is shown in FIG.
, The nine photometric elements 191a to 191i such as silicon photodiodes corresponding to the respective areas of the light distribution control element 16 divided into nine areas, and the photometric element 1
Photometric circuits 193a to 193i for detecting that the light intensity of the subject existing in each area reaches a predetermined value by the photometric signals from 91a to 191i. FIG. 7 shows each photometric circuit 19
3a to 193i are shown in detail, and the photometric circuits 193a to 1
93i is an operational amplifier 1931 and a diode 1932
And a transistor 1933 whose on / off is controlled by the output of the operational amplifier 1931, and a low-voltage power supply 11 flowing between the terminals B and A when the transistor 1933 is conductive.
From the capacitor 1934 which integrates the current from the comparator 1936 and the comparator 1936 which compares the reference voltage 1935 and the voltage between both terminals of the capacitor 1934 and outputs a high level signal to the terminal C when the voltage between both terminals of the capacitor becomes equal to or higher than the reference voltage. Become.

The operation of the flashlight illuminating device configured as described above will be described. In order to simplify the description, a case where the object scene is divided into three as shown in FIG. 8 will be described. Here, the light distribution control element corresponding to the left side region L is 16L, the light distribution control element corresponding to the central region C is 16C, and the right side region R.
Let 16R be the light distribution control element corresponding to, the photometric element corresponding to the left area L be 191L, the photometric element corresponding to the central area C be 191C, and the photometric element corresponding to the right area R be 191R. For other parts, L,
A description will be given with R and C attached.

When the switch 10S of the flash lighting device 10 is closed, the low voltage of the low voltage power source 11 is supplied to the booster circuit 12 and boosted to a high voltage of, for example, about 100 volts.
The high voltage from the booster circuit 12 is rectified by the diode 13a to charge the first capacitor 13b, and
The second capacitor 15b is rectified by the diode 15a.
To charge. When the first capacitor 13b is fully charged, the neon tube 13c lights up. At this time, the trigger switch 18d of the flash control circuit 18 is open and the flash tube 141
Is not triggered, the flash tube 141 does not emit light. On the other hand, although the second capacitor 15b is also fully charged, the output terminals C of the photometric circuits 193L to 193R are at a low level and the thyristors 172L to 172R are closed, so that no voltage is applied to each PLZT 161. The light incident on the light distribution control elements 16L to 16R is ready to be emitted.

When shooting is started by operating the release button and a flash light start signal is output from the CPU 31 of the camera 30, the switch 18d of the flash light control circuit 18 is closed,
A high voltage is generated on the secondary side of the trigger transformer 18c to trigger the flash tube 141. Since the voltage charged in the first capacitor 13b is applied between both terminals of the flash tube 141, flashing is started by such a trigger.
The light emitted from the flash tube 141 is reflected by the reflection shade 142, passes through the light distribution control elements 16L to 16R, and illuminates the subject. At this time, the light distribution control elements 16L-16
Each light transmittance of R is 100%. The reflected light from the subject passes through the lens 192 and the photometric elements 191L and 191.
It is incident on C and 191C.

The transistors 1933 of the photometric circuits 193L to 193R are turned on by the photometric signals from the photometric elements 191L to 191R to charge the capacitor 1934.
Now, assuming that the reflectances of the subjects in the regions L, C, and R are substantially equal, the photocurrent of the photometric element 191L that receives the reflected light from the subject in the closest region L is the highest, and then the light of the photometric element 191C is the same. The order of the current is the photocurrent of the photometric element 191R. Therefore, the voltage between both terminals of the capacitor 1934 of the photometric circuit 193L corresponding to this is first determined by the reference power source 1
Higher than the voltage at 935. As a result, first, the comparator 1936 of the photometric circuit 193L outputs a high level signal to the terminal C. As a result, the thyristor 172L is turned on, the voltage of the second capacitor 15b is applied to the PLZT 161 corresponding to the region L, and the light distribution control element 16L.
The light transmittance of is almost zero, and the irradiation of the illumination light to the region L is stopped. Next, the photometric circuit 19 corresponding to the area C
When 3C detects the predetermined light amount, the light transmittance of the light distribution control element 16C becomes zero, and finally when the photometric circuit 193R corresponding to the region R detects the predetermined light amount, the light distribution control element 1
The light transmittance of 6R becomes zero.

After that, the charge of the first capacitor 13b becomes less than a predetermined value and the light emission of the flash tube 141 is stopped.
Further, when the voltage between both terminals of the first capacitor 13b becomes equal to or lower than a predetermined value, the junction FET of the switching circuit 173 is connected.
173a is turned off, and thyristors 172L to 172R are turned off.

According to such an embodiment, the PLZT16
The second capacitor 15b for accumulating the electric energy applied to 1 is charged by the booster circuit 12 like the first capacitor 13b for flash light, so that it is not necessary to provide a dedicated booster circuit or the like, and the circuit configuration is simplified. Can be converted.

A switching circuit 27 as shown in FIG.
Alternatively, the thyristors 172a to 172i may be reset according to the step 3. In FIG. 6B, a transistor 273a is provided between the cathode of each thyristor and the ground line, and this transistor 273a is turned on / off by a T-type flip-flop 274b. T-type flip-flop 27
An output of an OR gate 273c is connected to 3b, and a pulse signal from a switch that is turned on when the front curtain starts traveling and a pulse signal from a switch that is turned on when the rear curtain finishes traveling are connected to the OR gate 273c, respectively. Has been done.

In such a switching circuit 273,
T-type flip-flop 2 by the pulse when the first curtain starts
The output of 73b changes from 0 to 1 and transistor 273
a is turned on, and the output of the T-type flip-flop 273b is changed from 1 to 0 by the pulse at the end of the trailing curtain, and the transistor 273a is turned off. In this way, the thyristors 172a to 172i can be reset when the flash photography is completed.

In the above, the field is divided into 9
Although the dimming area is also divided into nine parts in accordance therewith, it may be divided into nine parts or less. Again,
The amount of light reflected from the subject is measured, and when the value exceeds a predetermined value, the light transmittance of the light distribution control element is almost 100.
However, the present invention can also be applied to a device in which the distance to each subject is obtained in advance and the light transmittance is controlled to be lower for closer subjects before the start of light emission. Similarly, the present invention can also be applied to those in which pre-emission is performed in advance of photographing regardless of the distance and the amount of reflected light in each area is measured, and the light transmittance of each area is preset based on the result.

Furthermore, instead of PLZT, KH ₂ PO ₄ , NH ₄ H ₂ PO
Bulk electro-optic modulators such as ₄ , Bi ₁₂ SiO ₂₀ may be used. Further, a bulk type electro-optical modulator, such as PLZT, which applies a voltage in a direction orthogonal to the light traveling direction instead of applying a voltage can also be used. LiNBO ₃ and LiTa are typical materials.
_{O 3, BaNaNa 5 O 15,} Sr X Ba 1-X Nb 2 O 6, PbO X NbO 3 , etc. (x is an arbitrary number) and the like. In this case, the transparent electrode is unnecessary.

In the above, the luminous flux reflected by the reflection shade is controlled by the light distribution control element for each area, but the reflection surface of the reflection shade is divided into a plurality of areas in the same manner as described above. The reflectance of each partitioned area may be variably controlled. In this case, the reflectance can be controlled by using an element such as an ECD (electrochromic device) on the reflecting surface.

[0031]

As described in detail above, according to the present invention, the second charge storage circuit for storing the electric energy applied to the light quantity control element is arranged in parallel with the first charge storage circuit for flash tube light emission. Since the second charge storage circuit is provided and charged by the same booster circuit as the first charge storage circuit, the structure of the electric circuit is not complicated, and the size and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration.

FIG. 2 is a circuit diagram showing details of FIG.

FIG. 3 is a view showing the inside of a light emitting part by cutting.

FIG. 4 is a perspective view showing the principle of a translucent ceramic forming a light distribution control element.

FIG. 5 is a diagram showing a constant voltage circuit connected to a translucent ceramic.

FIG. 6 is a diagram showing a switching circuit for resetting a thyristor.

FIG. 7 is a diagram showing details of a photometric circuit.

FIG. 8 is a diagram showing a scene divided into three parts.

[Explanation of symbols]

10 Flash Lighting Device 11 Low Voltage Power Supply 12 Booster Circuit 13 First Charge Storage Circuit 13b First Capacitor 14 Light Emitting Section 15 Second Charge Storage Circuit 15b Second
Condensers 16, 16a to 16i Light distribution control element 17 Pass control circuit 18 Flash control circuit 19 Photometric circuit 161 PL
ZT 162,163 Transparent electrode 164 Polarizing plate 165 Analyzing plate 171a-
171i constant voltage circuit 191a to 191i photometric element 193a to
193i photometric circuit

Claims (1)

[Claims] 1. A low-voltage power supply that generates a low voltage, a booster circuit that boosts a low voltage applied from the low-voltage power supply to a high voltage, and a first energy-storing electric energy generated by the booster circuit.
A charge accumulating means and a light emitting section which emits light by the electric energy accumulated in the first charge accumulating means, wherein the electric energy generated by the booster circuit is accumulated
Of the electric charge accumulating means and the light quantity adjusting means arranged in the passage optical path of the flash light projected outward from the light emitting portion and adjusting the quantity of the passing light according to the high voltage applied from the second electric charge accumulating means. And a flash illumination device.