JPS58209050A - Strobe flush tube - Google Patents

Abstract

PURPOSE:To perform automatic strobe photographying stably even for close distance, by providing a strip having conductive surface extending in the longitudinal direction of a flush tube between the anode and cathode of the flush tube while one end is contacting with the trigger electrode on the surface of the flush tube. CONSTITUTION:A bulb 1 made of a thin transparent glass for encapsulating Xenon gas is provided with an anode 2 and cathode 3 at opposite ends. A trigger electrode 4 composed of a conductor is formed into a strip and secured on the surface in the circumferential direction of the bulb 1. The conductive strip 5 is formed with a thin rod having conductive surface such as a lead, where one end is connected to the electrode 4 while the other end is secured to the surface of the bulb 1 to extend toward the anode 2 in parallel with the longitudinal direction of the bulb 1. Consequently the astable section of the light emission characteristic at th rising portion can be eliminated, to increase the light emission gradually in proportion to the flux even for the automatic strobe photographying for close distance thus to control the exposure properly.

Description

DETAILED DESCRIPTION OF THE INVENTION In particular, the present invention relates to a robot flash tube for improving the rising edge of light emission characteristics, which is important during autostroboscopic photography.

An auto strobe measures the brightness of a subject illuminated by a flash tube, stops firing when the amount of reflected light reaches a predetermined value, and adjusts the flash duration so that the amount of light on the image plane remains constant. control.

Therefore, in auto strobe photography where the subject is at close range, the amount of light received is short-term, and the amount of light reflected from the subject is stronger than in auto strobe photography when the subject is far away. When the predetermined value is reached, the flash tube stops emitting light in a short time. In other words, in close-range autostrobe photography, the flash tube's light emission time is short (light emission near the peak of the light emission characteristics).

On the other hand, as shown in the graph in Figure 1 showing the luminescence characteristics of the rising part of a typical V-type flash tube, the luminance is not proportional to time and is fine and irregular immediately after the start of discharge light emission. It is known that there is a so-called unstable region where the

Therefore, when shooting with auto flash, especially when shooting at close range, the amount of light emitted from the flash tube in the unstable region accounts for a large proportion of the total amount of light emitted, so the amount of light reflected from the subject also increases. The overall change will be irregular. This causes a photometry error in a photometry circuit that converts the received reflected light into a photocurrent and integrates it directly into the photoelectric generator 2 capacitor.
4017, where the brightness level corresponds to the magnitude of the received reflected light is compared with the level corresponding to the film sensitivity and aperture value, the brightness level changes irregularly. Larger photometry error7
This has the disadvantage that an error occurs in the exposure amount controlled based on this photometry, making it impossible to always obtain an appropriate and constant amount of light on the image plane.

The inventiveness is related to the above circumstances, especially the light emission that becomes an auto strike difference at close range! Removed the unstable area in the standing part of the change ■
The purpose of this invention is to provide an L-r-bore flash tube for ~.

The inventor has developed an electrically conductive device that contacts the trigger electrode on the flash tube. 1; By arranging the body so as to extend toward the anode side, the light emitting characteristics of the rising part of the flash tube can be made into a smooth curve in which the luminous flux continuously increases in proportion to time. discovered.

The uninvented strobe flash tube is based on such a discovery, and comprises a stroboscopic flash tube having a material on the surface of the flash tube, extending along the length of the flash tube between the cathode and the anode of the flash tube, and having one end in contact with a trigger electrode. It is characterized by having a conductive strip on the surface.

The conductive band may be made of a lead wire, but if a conductive film is formed in a band shape by metal oxide sputtering or the like, it can be mass-produced and the manufacturing process can be significantly reduced. be shortened.

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

FIG. 2 is a front view showing a strobe flash tube according to an embodiment of the present invention, and FIG. 3 is a graph showing the light emission characteristics of the rising portion of the strobe flash tube shown in FIG. A tube 1 made of elongated transparent glass that seals xenon gas has an anode 2 and a cathode 3, which are discharge electrodes, at both ends thereof. A trigger electrode 4 made of a conductor to which a high voltage is applied to cause electron emission from the cathode 3 at the start of discharge light emission.
is formed into a band shape and is fixed on the surface of the tube 1 in the circumferential direction. The conductive band 5 has a thin bar shape and is formed of, for example, a lead wire having a conductive surface 2, one end of which is in contact with the trigger electrode 4, and the other end is parallel to the length direction of the bulb 1 and extends toward the anode 2. It is fixed to the surface of the tube 1 as shown in FIG. 4 - What is important here is that at least the surface of the conductive strip 5 has conductivity 2 and that at least this surface is in a conductive state with the trigger electrode, so as long as this satisfies Z. For example, a metal oxide such as indium oxide or tin oxide may be formed in the form of a film so as to be in contact with the trigger electrode 4.

Here, to describe one experimental result in this example, tube 1
The xenon gas sealed inside is 350mmHg~6
5 0g) Under the conditions of I-I, j17, the diameter is 0. 2
If one lead wire with a length of 50 inches to 100% of the distance from the cathode 3 to the anode 2 is installed within the range of 0.3 mm to 0.3 mm, the result will be as shown in Figure 3. The light emission characteristics at the rising edge of the light emitting device have eliminated the unstable region shown in the conventional example shown in FIG. 1, and have become a smooth curve in which the luminous flux gradually increases in proportion to time.

Note that there are various types of flash tubes with different shapes of the bulb 1 and the shapes of the discharge electrodes of the anode 2 and cathode 3, and the light emitting characteristics of the rising part of the flash tubes are also different. The light emitting characteristics of the rising part are improved depending on the type of terminal (4) where the contact part is wide and narrows towards the tip (or where it extends in a spiral shape towards the anode 2), and the number of terminals (4). It may be changed as appropriate so that the

As explained in detail above, the strobe flash tube of the present invention is provided with a conductive strip on the surface of the flash tube, one end of which is in contact with the trigger electrode, and the other end of which extends toward the anode. By removing the area and creating a smooth curve in which the luminous flux gradually increases in proportion to time, even when shooting with an auto strobe at close range, the luminous flux from the flash tube gradually increases in proportion to time. Avoid photometry error 7 (be able to control the exposure amount appropriately and always obtain a constant amount of light on the image plane).

[Brief explanation of the drawing]

Fig. 1 is a graph showing the light emitting characteristics of the rising part of a conventional flash tube. Fig. 2 is a front view of a strobe flash tube showing an embodiment of the present invention. Fig. 3 is a graph showing the strobe flash tube shown in Fig. 1. 2 is a graph showing light emission characteristics 2 at the rising edge of FIG. 1...Tube 2...Anode 3...
・・・・Cando 4・・・・・・・・・Trigger electrode 5
・・・－・・・・・・Conductive band

Claims (5)

[Claims] (1) A strip is provided on the surface of the flash tube, extending in the length direction of the flash tube between the cathode and anode of the flash tube, and having at least one surface electrically conductive and in contact with the trigger electrode at one end. Features a strobe flash tube. (2) The strobe flash tube according to claim 1, wherein the conductive band has a width of 0.2 mm to 0.3 mm. (3) The strobe flash tube according to claim 1 or 2, wherein the conductive band has a length that is 50% to 100% of the distance between the cathode and the anode. (4) The strobe flash tube according to claim 1, 2, or 3, wherein the conductive band is a conductive film made of a metal oxide. (5) The strobe flash tube according to claim 1, 2, or 3, wherein the conductive band has a circular cross section.