Photography – With object illumination for exposure
Reexamination Certificate
2000-09-07
2002-10-15
Gray, David (Department: 2851)
Photography
With object illumination for exposure
C396S201000, C396S206000, C396S311000, C396S317000
Reexamination Certificate
active
06466744
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a strobe circuit, to which another electronic circuit or electronic element is added, and a printed circuit board for strobe, which comprises two circuit boards, and also relates to a lens-fitted film unit and a camera, which incorporates the abovementioned strobe circuit or printed-circuit board for strobe.
Conventionally, quite a few lens-fitted film units, incorporated with a strobe, have been put in the market.
FIG. 1
shows an example of the strobe circuit diagram employed for such lens-fitted film units.
In
FIG. 1
, when main switches S
1
, S
2
are turned ON by an external operation, the electronic current, fed from battery B, flows into transistor T
R
through resistor R
1
to start the oscillation, by which the high-voltage of 300-350 volts is induced at the secondary winding of oscillation transformer T. The induced electronic current from the secondary winding is rectified by diode D, and the rectified electronic current flows into main-capacitor C
M
and trigger-capacitor C
T
, serially connected with resistor R
1
, to charge them. When main-capacitor C
M
is charged to a predetermined voltage, light-emitting diode D
L
, serially connected with resistor R
2
, emits light.
When capturing image, trigger-switch S
T
turns ON in conjunction with the opening operation of shutter blinds. Then, the closed circuit, including trigger-capacitor C
T
, trigger-switch S
T
, the primary winding of trigger-transformer T
C
and main switches S
1
, S
2
, is formed to discharge the electronic charge stored in trigger-capacitor C
T
. As a result, the further high-voltage is induced in the secondary winding of trigger-transformer T
C
, and the induced high-voltage is applied to the trigger-electrode of xenon tube Xe, in which electrons, isolated from the cathode, impinge with ionized xenon atoms to excite the xenon atoms. Thus, xenon tube Xe emits the strobe light associating with the discharging action of main-capacitor C
M
.
Since it is a primary subject for the lens-fitted film unit to reduce its price as low as possible, it is difficult to equip various kinds of image capturing mechanisms in it. Nevertheless, consumers desire that more image capturing mechanisms are incorporated in the lens-fitted film unit, in order to enjoy the image capturing with better photographic images.
Although quite a few lens-fitted film units, incorporated with a strobe circuit, have been put in the market as aforementioned, the strobe circuit is utilized only for activating the strobe lighting in such lens-fitted film units, as a matter of course. The parts, included in the strobe circuit, however, are relatively expensive, and the battery and the main-capacitor require large spaces. Therefore, it has been quite wasteful for lens-fitted film units to limit the purpose of the strobe circuit within the strobe lighting.
To utilize the strobe circuit more efficiently, it may be possible to incorporate new electronic element and/or electronic circuit, having a certain added value, in the strobe circuit. Such new electronic element or electronic circuit, however, usually requires a separate power source, which extraordinarily raises the total cost of the apparatus concerned. This problem is specifically serious for the strobe device of the lens-fitted film unit, the price of which should be reduced as low as possible.
SUMMARY OF THE INVENTION
To overcome the abovementioned drawbacks in conventional strobe devices, it is the first object of the present invention to provide a strobe device, which makes it possible to equip a new function in the strobe device by adding a little electronic circuit or some electronic parts to the fundamental circuit for strobe lighting.
Further, sometimes, it is difficult to mount an added circuit, having a new photographic function, on the small sized printed circuit board, which already mounts parts for the fundamental circuit for strobe lighting. To solve this problem, the second object of the present invention is to provide a combination of two printed circuit boards, strictly coupled to each other, which is disposed in a vacant space of a lens-fitted film unit or a camera.
Accordingly, to overcome the cited shortcomings, the abovementioned objects of the present invention can be attained by a strobe device, a lens-fitted film unit and a camera described as follow.
(1) A strobe device, comprising: a strobe light-emitting tube to emit a strobe light; a main-capacitor coupled in parallel to the strobe light-emitting tube, so as to supply a luminous energy to the strobe light-emitting tube; a trigger-transformer to apply a trigger-voltage to a trigger-electrode of the strobe light-emitting tube; a trigger-section to activate a light-emitting action of the strobe light-emitting tube; a trigger-capacitor, coupled to the main-capacitor with a resistor, to store an electronic charge, which is discharged to the trigger-transformer when the trigger-section turns ON; and an operating section driven by a part of an electronic charge, stored in the main-capacitor, flowing through the resistor when the trigger-section turns ON to activate the light-emitting action of the strobe light-emitting tube.
(2) The strobe device of item 1, wherein a closed circuit, serially connecting the trigger-capacitor, the trigger-section and a primary winding of the trigger-transformer, is formed when the trigger-section turns ON, and simultaneously, another closed circuit, serially connecting the main-capacitor, the operating section, the resistor, the trigger-section and the primary winding of the trigger-transformer, is formed.
(3) The strobe device of item 1, wherein the operating section is a constant-voltage generating element.
(4) The strobe device of item 3, wherein the constant-voltage generating element is a zener diode.
(5) The strobe device of item 4, wherein an anode of the zener diode is coupled to a negative pole of the main-capacitor.
(6) The strobe device of item 3, wherein an added circuit, which is driven by a voltage-source generated by the constant-voltage generating element, is coupled in parallel to the constant-voltage generating element.
(7) The strobe device of item 6, wherein the added circuit is a light-intensity regulating circuit, which controls an amount of the strobe light emitted from the strobe device, in response to an amount of the strobe light reflected from a subject.
(8) The strobe device of item 7, further comprising: a first printed circuit board on which electronic parts, constituting a fundamental circuit for a strobe lighting, including at least a voltage-boosting circuit, a charging circuit and a illumination circuit, are mounted; and a second printed circuit board on which electronic parts, constituting an electronic circuit other than the fundamental circuit, are mounted, wherein the first printed circuit board and the second printed circuit board are coupled to each other by means of a conductive member having an electronic conductivity, and the light-intensity regulating circuit is equipped on the second printed circuit board.
(9) The strobe device of item 8, wherein the first printed circuit board and the second printed circuit board are coupled to each other by means of at least the two conductive members.
(10) The strobe device of item 1, wherein the operating section is a light-emitting diode.
(11) The strobe device of item 10, wherein a cathode of the light-emitting diode is coupled to a negative pole of the main-capacitor.
(12) A lens-fitted film unit equipped with a strobe device, comprising: a main-body; a photographic lens; a shutter; and a photographic film loaded in the main-body, wherein the strobe device comprises, a strobe light-emitting tube to emit a strobe light, a main-capacitor coupled in parallel to the strobe light-emitting tube, so as to supply a luminous energy to the strobe light-emitting tube, a trigger-transformer to apply a trigger-voltage to a trigger-electrode of the strobe light-emitting tube, a trigger-section to activate a light-emitting action of the strobe light-
Hosaka Takao
Suzuki Kijiro
Blackman Rochelle
Cantor & Colburn LLP
Gray David
Konica Corporation
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