JPH0522221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid crystal display board having a 3-digit, 7-segment numerical display section for displaying film sensitivity information, light emission angle information, etc., and a drive circuit for this liquid crystal display board. and a DC that constitutes the power supply section.
- A strobe device equipped with a waste prevention circuit that forcibly stops the oscillation operation of the DC converter circuit under predetermined conditions, wherein the numeric display section of the liquid crystal display board can also be used to display the operating status of the waste prevention circuit. It is related to the device.

Conventional technology Conventionally, in strobe devices, film sensitivity,
For example, Japanese Patent Application Laid-Open No. 1983-1980 shows a device that displays the set aperture value of a camera using a 7-segment numerical display.
A device such as that proposed in Publication No. 4133 is well known. This device calculates the flash control range of the strobe device from film sensitivity and aperture value information, and
The result is displayed, and the 7-segment numerical display is used only to confirm the setting information.

On the other hand, Japanese Patent Application Laid-Open No. 50-120873 discloses that in a camera equipped with a 7-segment display for displaying photographing information, the display is displayed even when a drop in the power supply voltage of the camera is detected. A battery checker configured to indicate the drop in power supply voltage has been disclosed and is well known.

Further, a display device configured to display numbers or alphabetic characters on a 3-digit, 7-segment number display as described above is also well known from Japanese Utility Model Application Publication No. 56-38337.

On the other hand, various waste prevention circuits have been proposed or put into practical use for the purpose of preventing energy wastage or forgetting to turn off the power switch in strobe devices.

For example, in Japanese Patent Application Laid-Open No. 52-20826, there is a DC-DC
A strobe device that stops the oscillation operation of a converter circuit under predetermined conditions has been disclosed, and Japanese Patent Application Laid-Open No. 1982-
Publication No. 60424 describes an oscillation transformer having three windings: primary, secondary, and feedback, and a transistor that causes the oscillation transformer to oscillate by intermittent current flowing through the primary winding, and this transistor is made inoperable. A strobe device including a switching circuit is disclosed, in which a display means is connected to the primary winding and operates during an off period of the transistor during oscillation operation.

Problems to be Solved by the Invention As described above, various display means have been proposed or put into practical use in strobe devices.

However, when it comes to displaying or confirming the operating status of the above-mentioned waste prevention circuit, it still has the disadvantage that it cannot be easily performed as described below.

That is, the device disclosed in Japanese Unexamined Patent Publication No. 52-20826 mentioned above only discloses that it is equipped with a waste prevention circuit, and cannot display or check its operating state.

Furthermore, the device disclosed in Japanese Patent Application Laid-open No. 56-60424 is
It is characterized by having a display means that operates during the off period of the transistor that causes the oscillation transformer to oscillate,
It is possible to notify that the oscillation of the DC-DC converter circuit has stopped. Looking at the notification structure, the above-mentioned display means is provided in the primary winding of the oscillation transformer, and on the other hand, the above-mentioned oscillation is activated when the power switch is turned off. This also results in a stop if turned off.
Even when the power supply switch is turned off, the same notification operation as when the waste prevention circuit is activated is performed, making it difficult to distinguish between them, which is inconvenient in terms of displaying or confirming the operating status of the waste prevention circuit. For example, when attempting to restart the oscillation of a DC-DC converter circuit, if it is not possible to distinguish whether the oscillation stopped was due to the power switch being turned off or due to the operation of the waste prevention circuit, it may be necessary to operate the power switch again. It is not possible to immediately determine whether it is necessary to reset the waste prevention circuit or to reset the waste prevention circuit, resulting in an inconvenience of poor operability.

The present invention was developed in consideration of the above-mentioned disadvantages, and it is possible to always use film sensitivity information etc. to indicate that the oscillation of the DC-DC converter circuit is stopped not by turning off the power but by the operation of the waste prevention circuit. It is an object of the present invention to provide a strobe device that can be recognized by a user of the strobe device by displaying alphabetic characters on the numeric display section of a liquid crystal display board that displays .

Means for Solving the Problems The strobe device according to the present invention has three digits 7 for displaying film sensitivity information, light emission angle information, etc.
It is equipped with a liquid crystal display board having a numerical display section of the segments and a waste prevention circuit which has a drive circuit for this liquid crystal display board and forcibly stops the oscillation operation of a C-DC converter circuit constituting a power supply section under predetermined conditions. In a strobe device, the operating state of the waste prevention circuit is detected when the power is on, and the waste prevention circuit operates to control the DC-DC voltage.
An operation detection circuit that generates an output signal when the oscillation operation of the converter circuit stops, and a drive control that operates when the output signal is supplied and causes the numeric display section that normally displays numbers to display alphanumeric characters. and a control circuit that generates a signal and supplies it to the drive circuit.

Function Since the strobe device according to the present invention is configured as described above, the drive circuit of the liquid crystal display panel having the 3-digit, 7-segment number display section normally operates to display numbers on the number display section, On the other hand, when the operation detection circuit detects the operation of the waste prevention circuit and a drive control signal is supplied from the control circuit, the operation is performed so that the numerical display section displays alphabetic characters.

Therefore, the alphanumeric display on the numeric display section of the liquid crystal display panel can notify that the oscillation of the DC-DC converter circuit has been stopped due to the operation of the waste prevention circuit, rather than the power being turned off.

Embodiments Hereinafter, embodiments of the strobe device of the present invention will be described.

FIG. 1 is a block diagram showing an electrical circuit diagram of an embodiment of a strobe device according to the present invention.

In the figure, 1 indicates a power switch that controls the supply of power 2 to a well-known DC-DC converter circuit 3,
4 is a main capacitor charged by the DC-DC converter circuit 3; 5 is a trigger circuit for triggering the flash discharge tube 6; and 7 is a liquid crystal display panel having a 3-digit, 7-segment numerical display for displaying film sensitivity, for example. , 8 has a changeover switch 9 composed of, for example, a shift switch, which changes the display on the liquid crystal display board 7, and a drive circuit that causes the liquid crystal display board 7 to perform a display operation. A waste prevention circuit operates after a predetermined time to stop the oscillation operation of the DC-DC converter circuit 3 and prevent energy wastage; 11 is an operation detection circuit that detects when the waste prevention circuit 10 is in operation and generates an output signal; , 12 indicate control circuits that are operated by the output signal from the operation detection circuit 11 and control the operation of the drive circuit 8 in order to change the display on the liquid crystal display panel 7, respectively.

Now, regarding the operation of the strobe device according to the present invention having the configuration as described above, first, when the power switch 1 is turned on, the power source 2 is supplied to the DC-DC converter circuit 3.
starts operating, and the main capacitor 4 is charged.

When the trigger circuit 5 operates with the main capacitor 4 fully charged, the flash discharge tube 6 emits light.

Further, needless to be described in detail, the liquid crystal display panel 7 displays the desired film sensitivity value by the drive circuit 8 as soon as the power switch 1 is turned on, and furthermore, this display is configured to be changed by the operation of the changeover switch 9. There is.

On the other hand, as mentioned above, the waste prevention circuit 10 operates, for example, after a predetermined period of time has elapsed after the power switch 1 is turned on, and stops the oscillation operation of the DC-DC converter circuit 3. Although not included, a reset circuit is provided which resets the time measurement of the predetermined time when the trigger circuit 5 is activated or the changeover switch 9 is operated.

When waste prevention circuit 10 operates, operation detection circuit 11 detects this and generates an output signal to cause control circuit 12 to operate.

When the output signal from the operation detection circuit 11 is supplied, the control circuit 12 controls the operation of the drive circuit 8 of the liquid crystal display panel 7 .

The operation control of the drive circuit 8 by this control circuit 12 has priority over the control operation of the liquid crystal display board 7 by the drive circuit 8 up to that point, and no matter what the content of the numerical display that was displayed up to that point, it is This is a forced control to display characters. To give a concrete example, as shown in FIG.
Until then, for example, the ASA sensitivity value "400" was displayed in the state (a), but it was forcibly changed to "OFF" as shown in the same figure (b).
The control operation is like switching to an English character display.

Therefore, the user of the strobe device according to the present invention can confirm that the oscillation operation of the DC-DC converter circuit 3 is not due to the power switch 1 being turned off but due to the wastage prevention circuit 10 by seeing the above-mentioned English character display “OFF”. It is possible to recognize that it has stopped because it has started operating.

Effects of the Invention As described above, the strobe device according to the present invention has a liquid crystal display panel having a 3-digit, 7-segment numerical display for displaying film sensitivity, etc. In a strobe device having a waste prevention circuit that stops the oscillation operation of the DC converter circuit under predetermined conditions, an alphabetic character is displayed on the numeric display section of the liquid crystal display board based on the output from the detection circuit that detects the operation of the waste prevention circuit. Since the operation of the drive circuit of the liquid crystal display board is forcibly controlled, unlike the case where the operation of the waste prevention circuit is detected and the detection result is simply displayed, the operation of the drive circuit of the liquid crystal display panel is forcibly controlled, and the operation can be performed without adding any special display system, unlike the case where the operation of the waste prevention circuit is detected and the detection result is simply displayed. By using the numeric display section of the liquid crystal display board, which normally displays shooting information, as the alphanumeric display section, the oscillation stop of the DC-DC converter circuit does not mean turning off the power, but rather activates the waste prevention circuit. It has the effect of easily informing what is being done by the action.

In addition, since the strobe device according to the present invention can independently notify the operation of the waste prevention circuit as described above, when attempting to restart the oscillation operation of the DC-DC converter circuit, it can immediately recognize the operation necessary for restarting the oscillation operation of the DC-DC converter circuit. It also has the effect of being able to

Therefore, when restarting the oscillation operation of the DC-DC converter circuit, if there is a difference in operation between the restart operation of the power supply and the reset operation of the waste prevention circuit, for example, If the contents displayed by the display, such as film sensitivity, are not reset by the above-mentioned reset operation, but are reset by turning the power off again, that is, if the contents stored in the memory are erased by turning the power off, If you do not recognize the situation in which oscillation has stopped when re-operating the above, you should reset the waste prevention circuit, but if you mistakenly re-operate the power supply, the contents of the numerical display mentioned above may change. In other words, the inconvenience of having to reset the contents of the memory may occur, but the present invention has the advantage that the above-mentioned inconvenience does not occur because the oscillation stop situation can be notified and recognized. are doing.

It is needless to mention in detail that the amount of energy consumed in the display operation itself by the above-mentioned liquid crystal display panel can be extremely reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a strobe device according to the present invention, and FIGS. 2A and 2B are examples of display of a numeric display section of the strobe device according to the present invention. 1...Power switch, 2...Power supply, 3...DC
-DC converter circuit, 4...Main capacitor, 5
... Trigger circuit, 6 ... Flash discharge tube, 7 ... Liquid crystal display board, 8 ... Drive circuit, 9 ... Changeover switch, 10 ... Waste prevention circuit, 11 ... Operation detection circuit, 12 ... Control circuit .

Claims (1)

[Claims] 1. A liquid crystal display panel having a 3-digit, 7-segment numerical display section for displaying film sensitivity information, light emitting irradiation angle information, etc., and a DC-DC converter circuit that has a drive circuit for this liquid crystal display panel and constitutes a power supply section. In a strobe device equipped with a waste prevention circuit that forcibly stops oscillation operation under predetermined conditions, the operating state of the waste prevention circuit when the power is on is detected, and the waste prevention circuit operates to control the DC- an operation detection circuit that generates an output signal when the oscillation operation of the DC converter circuit stops;
a control circuit that operates when the output signal is supplied, generates a drive control signal for displaying alphabetic characters on the numeric display section of the liquid crystal display panel that normally displays numbers, and supplies the drive control signal to the drive circuit; The driving circuit is controlled to display numbers on the numeric display section at all times, and to display alphabetical characters on the numeric display section when the drive control signal is supplied, and to turn on the power when the alphanumeric characters are displayed. A strobe device that notifies the oscillation stop state of the DC-DC converter circuit due to the operation of the waste prevention circuit in the state.