Circuit for indicating the condition of the battery in a _photographic camera

• US 4,211,478 A
• Filed: 04/19/1978
• Issued: 07/08/1980
• Est. Priority Date: 04/19/1977
• Status: Expired due to Term

• Current Assignee: Agfa-Gevaert AG (Agfa-Gevaert N.V.)
• Original Assignee: Agfa-Gevaert AG (Agfa-Gevaert N.V.)
• Inventors: Egger, Gerhard, Borowski, Kurt, Huber, Theodor
• Primary Examiner(s): Gellner, Michael L.
• Application Number:
  US05/898,314
• Time in Patent Office: 811 Days
• Field of Search: 324/29.5, 320/48, 354/53, 354/60 L, 354/289, 354/60 E, 340/636
• US Class Current: 396/279
• CPC Class Codes: G03B 17/18 Signals indicating condition of a camera member or suitability of light indicating depth of field G03B13/30
• CPC Class Codes: G03B 43/00 Testing correct operation of photographic apparatus or parts thereof

Abstract

When the battery voltage is sufficient, and not nearing the point of insufficiency, a light-emitting diode is steadily illuminated. As the battery voltage decreases, the steady component of illumination decreases and also, when the decrease has proceeded to a certain extent, a superimposed pulsating component of illumination is introduced, causing the illuminated LED to begin to flicker, informing the user that the battery voltage is nearing insufficient values. As battery voltage drops further, the steady component of illumination ceases altogether, and the flicker converts to on-off blinking, indicating that the battery voltage is at the verge of an insufficient value. When the battery voltage drops further, the LED ceases to be illuminated. During part or all of the flicker phase, and/or during part or all of the blinking phase, the frequency of the pulsating component of illumination progressively increases with decreasing battery voltage, to create an effect of increasing urgency. In addition, or alternatively, at a certain point during pulsating illumination the frequency of the pulsating component is abruptly increased, likewise to create an effect of urgency.

Claims

1. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an indicator element;

a controllable-conductivity semiconductor element connected to the battery and to the indicator element and operative when conductive for carrying energizing current for the indicator element to cause the indicator element to generate a indication having a first character;

an astable multivibrator also connected to the battery and to the indicator element and operative when switched on for causing the indicator element to be energized to generate an indication having a different second character; and

means connected to the battery, the semiconductor element and the astable multivibrator operative for maintaining the semiconductor element conductive when the battery voltage is in a first range and operative for preventing and permitting oscillation of the astable multivibrator when the battery voltage is outside or in a second range, respectively, the astable multivibrator comprising an operational amplifier having inverting and non-inverting inputs, and RC-stage connected to the inverting input and a reference voltage divider connected to the battery and having a tap connected to the non-inverting input, said means including a semiconductor switch having a main-electrode path connected to the astable multivibrator to prevent and permit oscillation of the multivibrator in dependence upon the conduction state of the semiconductor switch and a voltage divider connected to the camera battery and having a tap connected to the control electrode of the semiconductor switch.

2. The circuit defined in claim 1, the main-electrode path of the semiconductor switch being connected in the operating-voltage line of the operational amplifier.

3. The circuit defined in claim 1, the main-electrode path of the semi-conductor switch being connected across the capacitor of the RC-stage of the astable multivibrator.

4. The circuit defined in claim 1, the operational amplifier having a feedback branch connected between its output and its non-inverting input, the feedback branch including a voltage-dependent resistor connected to undergo a change of resistance in dependence upon the battery voltage and thereby in dependence thereon vary the feedback resistance of the operational amplifier.

5. The circuit defined in claim 4, the feedback branch including at least two resistors, said means including at least one semiconductor short-circuiting switch connected across a respective one of the at least two resistors, said means including means for rendering the short-circuiting switch conductive or non-conductive in dependence upon the value of the battery voltage.

6. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an illuminatable indicator element and means connected to the indicator element and to the battery operative when the battery voltage is in a predetermined range of values for supplying the indicator element with energizing current illuminating the indicator element, the energizing current comprising a steady component resulting in a steady component of illumination of the indicator element and superimposed thereon a pulsating component resulting in a superimposed pulsating component of illumination of the indicator element giving the illumination of the indicator element the visually perceivable character of a distinct flicker visually distinguishable from simple steady illumination and visually distinguishable from on-off blinking action, the energizing current consisting at least predominantly of a steady current resulting in a visually perceived non-flickering steady illumination of the indicator element when the battery voltage is in a further range of values.

7. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an illuminatable indicator element and means connected to the indicator element and to the battery operative when the battery voltage is in a predetermined range of values for supplying the indicator element with energizing current illuminating the indicator element, the energizing current comprising a steady component resulting in a steady component of illumination of the indicator element and superimposed thereon a pulsating component resulting in a superimposed pulsating component of illumination of the indicator element giving the illumination of the indicator element the visually perceivable character of a distinct flicker visually distinguishable from simple steady illumination and visually distinguishable from on-off blinking action, the energizing current consisting substantially exclusively of a pulsating component when the battery voltage is in a further range of values resulting in an on-off blinking illumination of the indicator element visually distinguishable from the aforementioned flicker.

8. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an illuminatable indicator element and means connected to the indicator element and to the battery operative when the battery voltage is in a predetermined range of values for supplying the indicator element with energizing current illuminating the indicator element with energizing current illuminating the indicator element, the energizing current comprising a steady component resulting in a steady component of illumination of the indicator element and superimposed thereon a pulsating component resulting in a superimposed pulsating component of illumination of the indicator element giving the illumination of the indicator element the visually perceivable character of a distinct flicker visually distinguishable from simple steady illumination and visually distinguishable from on-off blinking action, the energizing current consisting at least predominantly of a steady current resulting in a visually perceived non-flickering steady illumination of the indicator element when the battery voltage is in a first range, the energizing current consisting at least predominantly of a pulsating current resulting in a visually perceived on-off blinking illumination of the indicator element when the battery voltage is in a second range, the on-off blinking illumination being distinguishable from the aforementioned flicker, said predetermined range in which the aforementioned flicker occurs being a range of battery voltage values shared by overlapping portions of said first and second ranges.

9. The circuit defined in claim 8, said means including means operative when the battery voltage is in said predetermined range for supplying the indicator element with an energizing current whose steady component is lower in value than the steady component furnished for establishing said non-flickering steady illumination, whereby to lower the steady component of illumination to an extend such that the pulsating component of illumination can readily be visually perceived despite its superposition upon an also perceivable steady component of illumination.

10. The circuit defined in claim 8, the pulsating current component increasing in frequency with decreasing battery voltage.

11. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an indicator element, and means operative when the battery voltage is in a high range for effecting simple steady illumination of the indicator element, when the battery voltage is in a lower range effecting a pulsating illumination of the indicator element with a frequency which progressively increases as the battery voltage progressively declines, and ceasing to illuminate the indicator element at all when the battery voltage has declined to a predetermined value.

12. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an illuminatable indicator element, and means operative for supplying illuminating current to the indicator element as a function of progressively decreasing battery voltage, the illuminating current effecting steady illumination of the indicator element when the battery voltage is in a range of high values, and as the battery voltage progressively decreases through a further range effecting superimposed steady and pulsating illumination of the indicator element with the steady and pulsating components of illumination being respectively low enough and high enough to result in a readily perceived flickering illumination readily distinguished from said steady illumination and also readily distinguishable from simple on-off blinking action, and as the battery voltage progressively decreases through a still lower range effecting on-off blinking action with a frequency which progressively increases as the battery voltage progressively decreases but then undergoes an abrupt and marked increase in frequency when the battery voltage has decreased down to a predetermined value.

13. In a still or motion-picture photographic camera having a battery, a battery-monitoring circuit operative for monitoring the condition of the battery and indicating battery condition to the user, the circuit comprising an indicator element, and means operative when the battery voltage has decreased and entered a predetermined range of values for effecting pulsating illumination of the indicator element with a frequency which progressively increases with progressive decrease of battery voltage but then undergoes an abrupt increase of frequency when the battery voltage has decreased to a predetermined value, whereby the progressive increase in the frequency of the pulsating illumination gives the user an effect of progressively increasing urgency whereas the abrupt increase in the frequency of the pulsating illumination gives the user an effect of extreme urgency.