Photography – With object illumination for exposure – Having artificial illumination termination control
Reexamination Certificate
2000-01-24
2002-02-05
Adams, Russell (Department: 2851)
Photography
With object illumination for exposure
Having artificial illumination termination control
C396S061000, C396S164000, C315S24100S
Reexamination Certificate
active
06345155
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a light-emission control apparatus and a camera apparatus, each having a light-emitting means for emitting light, which is controlled in accordance with the light reflected from an object of photography. The invention also relates to a method of controlling emission of light applied to an object of photography.
Strobolight photography is performed in some cases in order to take clear-cut photographs. Strobolight photography is achieved by using a light-emitting device such as a strobolight. The emission of light from the light-emitting device is controlled to accomplish optimal strobolight photography.
FIG. 1
illustrates a conventional light-emission control system designed for use in strobolight photography. The system shown in
FIG. 1
is operated in the following way to effect strobolight photography.
A light-emitting device
102
starts emitting light in response to a light-emission request made by the microprocessor unit (MPU) incorporated in a camera apparatus. A light-receiving element
103
receives the light reflected from an object
200
of photography. The output of the light-receiving element
103
is supplied to capacitors
104
and
105
and stored therein in the form of an electric charge. A voltage V
1
that corresponds to the electric charge stored in the capacitors
104
and
105
is compared with a reference value V
s
. When the voltage V
1
reaches the reference value V
s
, a comparing section
106
outputs a light-emission stop request. Upon receipt of the light-emission stop request the light-emitting device
102
stops emitting light, thereby controlling the emission of light. A resistor
107
determines the current accumulated by the capacitors
104
and
105
. It should be noted that the capacitor
105
is connected to the ground by a switch
108
. The switch
108
is changed over under the control of the microprocessor unit
101
. When the switch
108
is so changed over, the capacitance of the charge-accumulating section is changed, thereby altering the characteristic of voltage transition to the reference value V
s
.
FIG. 2
shows how the voltage V
1
changes with time.
FIG. 3
illustrates how the voltage V
1
changes when the light-emitting device
102
stops emitting light. The comparing section
106
generates a light-emission stop request when the voltage V
1
reaches the reference value V
s
. As seen from
FIG. 3
, the voltage V
1
ceases to change when the light-emitting device
102
stops emitting light in response to the light-emission stop request.
In the conventional light-emission control system, the capacitors
104
and
105
and the comparing section
106
constitute a section for detecting the amount of light the light-receiving element
103
receives. The capacitors
104
and
105
and the section
106
process analog data. Inevitably, the precision of the light-emission control greatly depends on the characteristics of the capacitors
104
and
105
, the discharging of these capacitors and the performance of the comparing section
106
.
Since the capacitors
104
and
105
and the comparing section
106
are major components of the light-emission control system, the operation characteristics of the system must be adjusted by using additional circuit components such as a variable resistor or an electronic volume during the manufacture of the system. The adjustment of operation characteristics is cumbersome and will increase the manufacturing cost of the light-emission control system.
Further, it is desired that the degree of freedom of controlling the light-emitting device
102
be enhanced to increase the precision of the light-emission control.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in view of the foregoing. The object of the present invention is to provide a light-emission control apparatus, a camera apparatus and a light-emission control method, which can control the emission of light with high precision and at low cost and which can increase the degree of freedom of controlling the light-emitting device used.
To achieve the object, a light-emission control apparatus according to the invention comprises: light-receiving means for outputting a light-reception signal corresponding to an amount of light received; analog-to-digital converting means for converting the light-reception signal to digital data; and control means for outputting a light-emission stop request to light-emitting means, thereby causing the light-emitting means to stop emitting light, when an integrated value obtained by integrating the digital data reaches a predetermined threshold value.
In the light-emission control apparatus, the light-emission stop request is output to the light-emitting means when an integrated value obtained by integrating the digital data reaches a predetermined threshold value.
That is, the light-emission control apparatus controls the light-emission preformed by the light-emitting means, in accordance with the output value of the light-receiving means.
To achieve the object, a camera apparatus according to the present invention comprises: an image sensing section for capturing an object image; light-emitting means designed to stop emitting light in response to a light-emission stop request; light-receiving means for outputting a light-reception signal corresponding to an amount of light received; analog-to-digital converting means for converting the light-reception signal to digital data; and control means for outputting a light-emission stop request to light-emitting means, thereby causing the light-emitting means to stop emitting light, when an integrated value obtained by integrating the digital data reaches a predetermined threshold value.
In the camera apparatus, the light-emission stop request is output to the light-emitting means when an integrated value obtained by integrating the digital data reaches a predetermined threshold value.
That is, in this camera apparatus, the light-emitting means stops emitting light in accordance with the digital output value of the light-receiving means.
The light-emission control apparatus according to the invention comprises: light-receiving means for outputting a light-reception signal corresponding to an amount of light received; analog-to-digital converting means for converting the light-reception signal to digital data; and control means for outputting a light-emission stop request to light-emitting means, thereby causing the light-emitting means to stop emitting light, when an integrated value obtained by integrating the digital data reaches a predetermined threshold value. The apparatus can therefore make the light-emitting means stop emitting light when the integrated value reaches the predetermined threshold value.
That is, the light-emission control apparatus can control the termination of the light emission effected by the light-emitting means, in accordance with the digital data, i.e., the output value of the light-receiving means.
The output value of the light-receiving means is converted to digital data. The digital data, not analog data, is processed to control the termination of the light emission. The apparatus can therefore control the emission of light with high precision.
The camera apparatus of the present invention comprises: an image sensing section for capturing an object image; light-emitting means designed to stop emitting light in response to a light-emission stop request; light-receiving means for outputting a light-reception signal corresponding to an amount of light received; analog-to-digital converting means for converting the light-reception signal to digital data; and control means for outputting a light-emission stop request to light-emitting means, thereby causing the light-emitting means to stop emitting light, when an integrated value obtained by integrating the digital data reaches a predetermined threshold value.
In other words, with the camera apparatus the termination of the light emission effected by the light-emitting means can be controlled in accordance with th
Shiono Toru
Tojo Takahiro
Adams Russell
Frommer William S.
Frommer & Lawrence & Haug LLP
Smith Arthur A
Sony Corporation
LandOfFree
Light-emission control apparatus camera apparatus and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Light-emission control apparatus camera apparatus and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light-emission control apparatus camera apparatus and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2982535