JP5430415B2 - Strobe device - Google Patents

Description

  The present invention relates to a strobe device for irradiating an irradiation target with strobe light as auxiliary light for photographing.

  For example, a strobe device built in a digital camera or the like is a subject that is irradiated with strobe light in order to enable shooting within a predetermined effective shooting range in a dark environment such as at night or in the rain. It irradiates toward. In such a strobe device, for example, a xenon tube (Xe tube) is used as a light-emitting tube, and an outer peripheral surface of the xenon tube is coated with a conductive transparent film called Nesa coating over the entire circumference. This nesa coating is pressed against an aluminum vapor deposition layer formed on the inner surface of the reflector (reflective shade).

  Thus, when the trigger voltage applied to the trigger terminal fixed to the reflector is applied to the xenon tube through the contact portion between the aluminum vapor deposition layer of the reflector and the nesa coating of the xenon tube, it is enclosed in the xenon discharge tube. The emitted xenon (Xe) gas is excited as a whole, and the emission current easily flows. When the emission current flows through the xenon tube, the xenon tube discharges and emits light.

  By the way, in Patent Document 1, in the irradiation angle variable strobe device that changes the irradiation angle by moving the arc tube in the direction of the light emission optical axis, the arc tube and the trigger terminal are connected by an electrically connecting spring member that can be deformed and expanded. Thus, there has been proposed a configuration in which a trigger voltage can always be reliably applied to the arc tube even if the arc tube is freely moved with respect to the reflector.

JP-A-62-273516

  However, in conventional strobe devices including those proposed in Patent Document 1, when light emission is repeated for a long period of time, a film in a portion in contact with the Nesa-coated reflector formed on the outer peripheral surface of the arc tube is formed. This disappears, and the resistance between the reflector and the nesa coating increases, so that the trigger voltage applied to the nesa coating is lowered, resulting in a problem that the light emission property is lowered and the light emission timing becomes unstable.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a strobe device that does not cause deterioration in light emission or instability of light emission timing even if light emission is repeated.

  In order to achieve the above object, an invention according to claim 1 is provided with an arc tube that is coated with a nesa coating over the entire circumference of an outer peripheral surface, and a reflector to which the nesa coating of the arc tube is pressed, and a trigger voltage is provided. A strobe device that applies light to the arc tube through a contact portion between the reflector and the Nesa coating to emit light from the arc tube, and includes a rotation mechanism that rotates the arc tube around its axis. To do.

  According to a second aspect of the present invention, in the first aspect of the present invention, the axial ends of the arc tube are rotatably supported by metal terminal bearings, the rotary shaft arranged in parallel with the arc tube, and the rotation The rotating mechanism is configured by a pair of belts wound between the shaft and the outer periphery of both ends of the arc tube in the axial direction.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the rotating mechanism rotates the arc tube by a predetermined angle for each predetermined number of times of light emission.

  According to the invention of claim 1, even if the nesa coating of the arc tube disappears due to light emission, the fresh nesa coating that has not disappeared by rotating the arc tube around its axis contacts the reflector. Even if light emission is repeated for a long period of time, the light emission property does not deteriorate, and the light emission timing does not become unstable.

  According to the second aspect of the present invention, when the rotating shaft of the rotating mechanism is rotated manually or automatically, the rotation of the rotating shaft is transmitted to the arc tube via a pair of pulleys and a belt, and the arc tube rotates. Therefore, a fresh nesa coating that has not disappeared can be brought into contact with the reflector, and a decrease in light emission due to repeated light emission for a long period of time can be prevented, and the light emission timing can be stabilized.

  According to the invention of claim 3, by rotating the arc tube by a predetermined angle every predetermined number of times of light emission, the fresh nesa coating can be brought into contact with the reflector before the nesa coating disappears. It is possible to prevent the deterioration, stabilize the light emission timing, and improve the durability of the strobe device. Note that labor can be saved by automatically rotating the arc tube by a predetermined angle for each predetermined number of times of light emission.

It is the perspective view which looked at the strobe device concerning the present invention from diagonally forward. It is the perspective view which looked at the strobe device concerning the present invention from the slanting back. It is the A section enlarged detail drawing of FIG. It is a partial side view of the main part of the flash device according to the present invention. It is a front view of the xenon tube of the strobe device according to the present invention. It is an electric circuit diagram of the strobe device according to the present invention.

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

  FIG. 1 is a perspective view of the strobe device according to the present invention as seen from an oblique front, FIG. 2 is a perspective view of the strobe device as seen from an oblique rear, FIG. 3 is an enlarged detail view of part A in FIG. FIG. 5 is a front view of a xenon tube of the strobe device, and FIG. 6 is an electric circuit diagram of the strobe device.

  The strobe device 1 according to the present embodiment is built in a digital camera or the like and emits strobe light in order to enable photographing within a predetermined photographing effective range even in a dark environment such as at night or in rainy weather. As shown in FIG. 1 and FIG. 2, an xenon tube 2 that is a light emitting tube that is long in the width direction and strobe light from the xenon tube 2 are irradiated to the object. A reflector 3 that reflects the light and a transparent lens (not shown) that covers the front surface (light emitting surface) of the reflector 3 are provided.

  The reflector 3 is disposed so as to cover a part of the xenon tube 2 from the back side, and includes a front reflecting portion (vertical wall) 3A and side reflecting portions (side walls) 3B formed at both side ends thereof. An aluminum vapor deposition layer is formed on the inner surface of the reflector 3, and an elliptical shape or a free-form surface close to an ellipse is adopted as the longitudinal cross-sectional shape of the front reflecting portion 3A so that as much light as possible can be controlled. The portion 3B is formed in a tapered shape that opens toward the front (light emission direction).

  A trigger electrode 4 is attached to the back surface of the reflector 3, and a metal terminal 5 extending from a trigger coil 18 (see FIG. 6) described later is connected to the trigger electrode 4.

  As shown in FIGS. 1 and 2, both ends of the xenon tube 2 pass through the left and right side reflecting surfaces 3B of the reflector 3 and protrude to the outside of the reflector 3, and the glass tube 2a of the discharge part is formed. A round bar-like electrode terminal 2b is inserted through the center of both left and right ends of the electrode. Then, in a predetermined axial length range of the outer peripheral surface of the glass tube 2a accommodated inside the reflector 3 of the xenon tube 2, as shown in FIG. 5, a nesa coating 6 that is a conductive transparent film is provided. It is coated all around. And this nesa coating 6 is press-contacted to the aluminum vapor deposition layer of 3 A of front reflection parts of the reflector 3, as shown in FIG.

  Thus, in the strobe device 1 according to the present embodiment, the electrode terminals 2b provided at both ends of the xenon tube 2 are supported by the bearings 8 formed at the tips of the metal terminals 7 (see FIG. 3 and FIG. 3). As a result, the xenon tube 2 can be rotated about its axis. The xenon tube 2 is rotated by a rotating mechanism 10, and the rotating mechanism 10 includes, as shown in FIGS. 1 and 2, a rotating shaft 11 disposed in parallel to the rear of the xenon tube 2, and The rotating shaft 11 and a pair of rubber belts 12 wound around the outer periphery of both ends in the axial direction of the xenon tube 2 are configured. Here, the xenon tube 2 is pulled with a predetermined force in the direction of the arrow (rear) in FIG. 2 by the rubber belt 12, so that the nesa coating 6 formed on the outer peripheral surface of the xenon tube 2 is deposited on the aluminum of the reflector 3. Pressed to the layer. It should be noted that the force for pulling the xenon tube 2 by the rubber belt 12 is sufficient that the nesa coating 6 is in contact with the aluminum vapor deposition, and if this force is too large, the contact resistance between the nesa coating 6 and the aluminum vapor deposition increases. The rotation of 2 is inhibited.

  Here, the configuration of the electric circuit and the light emission principle of the strobe device 1 according to the present embodiment will be described below with reference to FIG.

  The strobe device 1 includes a light emitting circuit 16 configured by providing a xenon discharge tube 2 and an IGBT (Insulated Gate Bipolar Transistor) 15 in a discharge loop of a main capacitor 14, a trigger capacitor 17 for exciting the xenon tube 2, and a trigger. A trigger means 19 including a coil 18 and an IGBT driver 20 for controlling ON / OFF of the IGBT 15 by controlling application of a gate voltage to the IGBT 15 based on a light emission signal transmitted from a CPU (not shown) are provided.

  Thus, the CPU (not shown) built in the camera body sets the light emission time of the xenon tube 2 using the brightness of the external light, the distance at which the focus is set, and the like as parameters, and turns on the light to the IGBT driver 20. The signal is output for the set time. Then, since the IGBT driver 20 applies the gate voltage to the gate 15a of the IGBT 15, the IGBT 15 is turned on and the trigger voltage charged in the trigger capacitor 17 of the trigger means 19 is boosted by the trigger coil 18 to be triggered electrode 4 To be applied. Then, the trigger voltage applied to the trigger electrode 4 is applied to the xenon tube 2 through a contact portion between the aluminum vapor deposition layer of the reflector 3 and the nesa coating 6 of the xenon tube 2, and the xenon sealed in the xenon tube 2. (Xe) The gas is entirely excited, and a light emission current (collector current) easily flows. At the same time, the light emitting circuit 16 becomes conductive, and a light emission current (collector current) flows from the main capacitor 14 to the xenon discharge tube 2 so that the xenon tube 2 discharges and emits light.

  As described above, when a predetermined set time elapses after the xenon tube 2 emits light, a light emission OFF signal is output from the CPU to the IGBT driver 20. Then, the application of the gate voltage from the IGBT driver 20 to the IGBT 15 is turned off, and when the gate voltage falls below a predetermined threshold value, the IGBT 15 is also turned off and the light emitting circuit 16 becomes non-conductive, and the light emission current (collector current) in the light emitting circuit 16 is turned off. ) Is interrupted and the light emission of the xenon tube 2 is stopped.

  Thus, when light emission is repeated in the strobe device 1, the film of the portion of the Nesa coating 6 that is coated on the outer peripheral surface of the xenon tube 2 that is in contact with the aluminum vapor deposition layer disappears, and the reflector 3 As described above, since the resistance between the nesa coatings 6 increases, the trigger voltage applied to the nesa coatings 6 decreases, causing problems such as a decrease in light emission and unstable light emission timing. In this embodiment, even if the nesa coating 6 of the xenon tube 2 disappears due to light emission, if the xenon tube 2 is rotated around its axis by the rotation mechanism 10, the fresh nesa coating 6 that has not disappeared is obtained. Since it contacts the aluminum vapor deposition layer of the reflector 3, the light emission is not deteriorated even by continuous light emission, and the light emission timing is unstable. It is not to become.

  That is, if the rotating shaft 11 of the rotating mechanism 10 is rotated manually or automatically, the rotation of the rotating shaft 11 is transmitted to the xenon tube 2 through a pair of rubber belts 12, and the xenon tube 2 rotates about its axis. Therefore, the fresh nesa coating 6 that has not disappeared can be brought into contact with the aluminum vapor deposition layer of the reflector 3 to prevent a decrease in light emission due to continuous light emission and to stabilize the light emission timing. Can do.

  By the way, in this embodiment, the number of times of applying the trigger voltage is counted on the camera body side, and the rotation mechanism 10 is driven and the xenon tube 2 is rotated by a predetermined angle every time the trigger voltage is applied 100 times. ing.

  Here, the single rotation angle of the xenon tube 2 is determined by the number of endurances required for the strobe device 1, and is obtained by the following equation in the present embodiment.

Rotation angle [°] = 360 [°] × (100 [times] ÷ endurance number [times])
Thus, by rotating the xenon tube 2 by a predetermined angle for every predetermined number of times of light emission, the fresh nesa coating 6 can be brought into contact with the aluminum vapor deposition layer of the reflector 3 before the nesa coating 6 disappears. Can be prevented, the light emission timing can be stabilized, and the durability of the strobe device 1 can be improved. Then, if the xenon tube 2 is automatically rotated by a predetermined angle every predetermined number of times of light emission as in the present embodiment, labor saving can be achieved.

  Here, Table 1 shows the results of an experiment on whether the flash device 1 emits light when the light emission signal is input 30 times while changing the trigger voltage, with or without the nesa coating 6.

低いトリガ電圧で発光した方がストロボ性能は高いことになるが、表１に示す結果によれば、ネサコーティング６がある場合はトリガ電圧が２１０Ｖで３０回の発光信号に対して３０回全て発光したのに対して、ネサコーティング６が消失して無くなっている場合にはトリガ電圧を２３０Ｖまで上げないと３０回の発光信号に対して３０回全て発光させることができないことが分かる。つまり、ネサコーティング６がある場合は無い場合よりも２０Ｖ低いトリガ電圧で発光させることができる。

Although the strobe performance is higher when light is emitted at a lower trigger voltage, according to the results shown in Table 1, when there is Nesa coating 6, the trigger voltage is 210V and light is emitted 30 times for 30 light emission signals. On the other hand, when the NESA coating 6 disappears and disappears, it can be understood that the light cannot be emitted 30 times for 30 light emission signals unless the trigger voltage is increased to 230V. That is, it is possible to emit light with a trigger voltage that is 20 V lower than when the Nesa coating 6 is present.

  The present invention is applicable to all strobe devices for cameras that use a light-emitting tube whose outer peripheral surface is coated with Nesa as a light source.

1 Strobe device 2 Xenon tube (arc tube)
2a Xenon tube glass tube 2b Xenon tube electrode terminal 3 Reflector 3A Reflector front reflector (vertical wall)
Side reflector of 3B reflector (horizontal wall)
4 Trigger electrode 5 Metal terminal 6 Nesa coating 7 Metal terminal 8 Bearing 10 Rotating mechanism 11 Rotating shaft 12 Rubber belt (belt)
14 Main capacitor 15 IGBT
15a IGBT gate 16 Light emitting circuit 17 Trigger capacitor 18 Trigger coil 19 Trigger means 20 IGBT driver

Claims (3)

An arc tube that is coated with nesa coating over the entire circumference of the outer peripheral surface, and a reflector to which the nesa coating of the arc tube is pressed, and a trigger voltage is emitted through a contact portion between the reflector and the nesa coating. In a strobe device for applying light to a tube and causing the arc tube to emit light,
A strobe device comprising a rotation mechanism for rotating the arc tube about its axis.   Both ends of the arc tube in the axial direction are rotatably supported by metal terminal bearings, and are wound between a rotation shaft arranged in parallel to the arc tube and the outer periphery of the rotation shaft and the axial end portions of the arc tube. The strobe device according to claim 1, wherein the rotating mechanism is configured by a pair of belts mounted.   The strobe device according to claim 1 or 2, wherein the rotating mechanism rotates the arc tube by a predetermined angle for every predetermined number of times of light emission.

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