JPS6327422Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a trigger device for a flash discharge light emitting device having a ring-shaped discharge tube.

As is widely known, this type of flash discharge light emitting device is often used as an illuminator for close-up photography. However, such a light emitting device has a ring-shaped light emitting section, and the light emitting section is attached to the tip of the camera lens barrel, making it difficult to illuminate the subject. Distribution becomes uniform. For this reason, while it is suitable for close-up photography of flat objects, when photographing three-dimensional objects, the result is a photograph with little sense of perspective.

On the other hand, when such a light emitting device is used to take a close-up photograph of a shiny object, there is a drawback that the light emitting portion appears as a ring-shaped image.

The purpose of this invention is to eliminate the above-mentioned drawbacks, and its feature is that by partially emitting light from a ring-shaped discharge tube, it creates shadows on the subject and gives a sense of perspective to the photograph. .

According to the present invention, the two main electrodes are connected to the main discharge capacitor, and in a flash discharge light emitting device equipped with a ring-shaped discharge tube that emits light when triggered by a trigger device, the two main electrodes are connected to the main discharge capacitor. two independent trigger electrodes A provided on one side of the discharge tube surface and the other side of the discharge tube surface,
B, a selection switch that connects the trigger electrodes A and B simultaneously or selected one to the trigger transformer, and when one of the trigger electrodes A or B is selected by the selection switch, the other trigger It consists of a changeover switch that connects electrode A or B to ground.

According to the above-mentioned present invention, in addition to making the entire discharge tube emit light, it is also possible to make only the discharge tube part on one side or the other side emit light depending on the shooting situation. It is possible to give a shading effect.

Embodiments of the present invention will be described below with reference to the drawings.

The drawing shows a ring-shaped discharge tube of a flash discharge light emitting device and a partial electric circuit attached thereto. In this drawing, 1 is a well-known ring-shaped discharge tube filled with xenon gas;
An anode 1a and a cathode 1b, which are main electrodes, are provided at symmetrical positions.
A main discharge capacitor 2 is connected to a and 1b. The main discharge capacitor 2 is a well-known capacitor that is charged to a high voltage during the preparation stage for light emission.

A and B are the trigger electrodes of the discharge tube 1 described above,
Trigger electrode A on the left side and trigger electrode B on the right side with the main electrodes 1a and 1b as a border are mutually independent electrodes. Note that these trigger electrodes A and B can be formed in the same manner as in the prior art, for example, by applying a conductive paint to the surface of the discharge tube 1 in a band shape. Reference numeral 3 designates an externally operable selection switch for selecting the trigger electrodes A and B. As shown in the figure, this selection switch 3 consists of a two-throw changeover switch, and connects terminals 3a, 3b, 3c, and 3d and a common terminal 3e. We are prepared. The terminal 3b is the trigger electrode A, and the terminal 3c is the trigger electrode B.
The common terminal 3e is connected to the secondary coil of the trigger transformer 4. The trigger transformer 4 is a well-known transformer that generates a high voltage in a secondary coil in response to the closing of a synchro switch (not shown).

Reference numeral 5 designates an externally operable changeover switch that selects and connects the trigger electrode A or B to earth, and is provided with terminals 5a, 5b, 5c, and a common terminal 5d. Then, connect the terminal 5a to the trigger electrode B
, connect terminal 5c to trigger electrode A,
Further, the common terminals 5d are respectively connected to the negative potential side circuit of the main discharge capacitor 2.

It is convenient if the selection switch 3 and the changeover switch 5 described above are configured to work together, and
These switches 3 and 5 can be configured as one switch device.

Next, the operation of the above embodiment will be explained.

When the selection switch 3 and the changeover switch 5 are turned on as shown by the solid lines in the figure, the trigger electrode A is selected, and when light emission is started in this state, the left half of the discharge tube 1 emits light. That is, if a high voltage is generated in the secondary coil of the trigger transformer 4 during the well-known trigger operation, this voltage is applied to the trigger electrode A via the terminals 3e and 3b of the selection switch 3, while the trigger electrode B is Since the discharge tube 1 is connected to the ground circuit through the terminals 5a and 5d of the changeover switch 5, only the left half of the discharge tube 1 forms a discharge path, and therefore the discharge tube 1 is connected to the main discharge capacitor 2.
Only the left half emits light due to the accumulated energy.

When the selection switch 3 and changeover switch 5 are switched as shown by the dotted lines in the figure, only the right half of the discharge tube 1 emits light. That is, in this switching state, the high voltage generated in the secondary coil of the trigger transformer 4 is applied to the trigger electrode B via the terminals 3e and 3c of the selection switch 3, and the trigger electrode A is applied to the terminals 5c and 5c of the selector switch 5. Since it is connected to the ground circuit via 5d, only the right half of the discharge tube 1 emits light in the same manner as described above.

When the selection switch 3 is operated to a position between the solid line and the dotted line shown in the figure and the terminals 3b and 3c are placed in the position, and the selector switch 5 is placed in the terminal 5b position, the entire discharge tube 1 emits light. That is, when the switches 3 and 5 are operated in this way, the high voltage generated in the secondary coil of the trigger transformer 4 is applied to the trigger electrodes A and 5.
Both of these electrodes A or B are disconnected from the ground circuit, while being applied to B simultaneously.

As described above, according to the present invention, the entire discharge tube or only one side or the other side can be made to emit light, so the method of illumination can be determined according to the shooting conditions and the state of the subject. For example, if you set the discharge tube so that only one side emits light, you can illuminate the subject diagonally from above and create appropriate shadows. The result is a photograph with a sense of perspective and gravity, and even if the subject is glossy, by illuminating it as described above, the image of the light-emitting part appearing together with the subject can be sufficiently eliminated.

Furthermore, when two trigger electrodes A and B are provided in one discharge tube as in the present invention, the excitation voltage that would have been applied to one trigger electrode is also induced to the other trigger electrode, causing the discharge tube to become However, in this invention, the excitation voltage is applied to one trigger electrode while the other trigger electrode is grounded, so there is no such drawback as mentioned above, and the part of the discharge tube Light emission is ensured.

In the above embodiment, the discharge tube 1 is shown in which the main electrodes 1a and 1b are located at symmetrical positions, but the present invention is a discharge tube in which the main electrodes 1a and 1b are located at asymmetric positions. can also be implemented in the same way.

[Brief explanation of the drawing]

The drawing shows one embodiment of the present invention, and is a simplified diagram showing a ring-shaped discharge tube and a partial electric circuit attached thereto. 1...Discharge tube, 1a, 1b...Main electrode, A, B
...Trigger electrode, 2...Main discharge capacitor, 3
...Selection switch, 4...Trigger transformer, 5
...changeover switch.

Claims (1)

[Scope of utility model registration request] The two main electrodes are connected to the main discharge capacitor,
In a flash discharge light emitting device equipped with a ring-shaped discharge tube that emits light when triggered by a trigger device, each of the above two main electrodes is provided on one side of the discharge tube surface and the other side of the discharge tube surface with the two main electrodes as boundaries. two independent trigger electrodes A and B; a selection switch that connects the trigger electrodes A and B simultaneously or a selected one to a trigger transformer;
A trigger device comprising a changeover switch that connects the other trigger electrode A or B to ground when one of the trigger electrodes A or B is selected by the selection switch.