JPH04115246A - Arc correcting mechanism for xenon lamp - Google Patents

Abstract

PURPOSE:To hold a magnet at a fixed position at all times and to stabilize arc discharging by arranging a roller rotatably in a hole bored in the rear peak part of a reflector and fitting the magnet for arc correction to the roller. CONSTITUTION:When a display device is tilted at a proper angle and light is projected on a screen, the xenon lamp 1 and a reflecting mirror 2 rotate corresponding to the angle. As the reflecting mirror 2 rotates, the roller 15 also rotates along the edge of the hole 14, but does not shift in position and is held at the same position. Further, a holding part material 17 is rotatable about the roller 15, so even if the roller 15 rotates, the material is held in a perpendicular state at all times to position the magnet 8 below the reflecting mirror 2 without fail. Therefore, even when the display device is used while tilted by more than a constant angle, the disorder of arc discharging due to convection can be corrected and the stable arc discharging is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for transmitting information such as images to films, photographic films, oil film light valves, liquid crystal light bulbs, etc. (hereinafter collectively referred to as carriers). a display device and an overhead 10 for displaying and enlarging and projecting this information;
This invention relates to an arc correction mechanism for a xenon lamp used in a dioctor device.

[Prior Art] Disgray devices and overhead projector devices illuminate a carrier on which information such as images is formed with a high-brightness light source, and project the transmitted light or reflected light onto a screen in an enlarged manner. It has excellent features such as high resolution, ability to project in bright rooms, and real-time display. A xenon lamp is usually used as a high-intensity light source for this type of device. A xenon lamp is filled with xenon gas, has a continuous spectrum similar to daytime sunlight from ultraviolet rays to infrared rays, and has excellent color rendering properties. but,
Its performance cannot be fully demonstrated unless various conditions are met. One of the conditions is the direction in which the electrodes are set. In other words, with the electrode axis of the xenon lamp vertical, ±1
If used within a range of 5°, the arc will be stable over a wide current range and the specified life will be maintained. ) When a reflecting mirror is used, the light utilization efficiency is improved by 20 to 30%, and it has the characteristic that a specified target can be maintained.

Therefore, normally, the first priority is to improve the light utilization efficiency, and as shown in FIG. I was using it.

However, when installed horizontally, the arc discharge 5 (FIG. 4) generated between the cathode 3 and anode 4 is unstable due to the convection 6 of xenon gas, resulting in a problem that the lamp life is shortened. That is, it is preferable that the arc discharge 5 is performed horizontally from the center of the xenon lamp, but the convection 6 of the xenon gas
If the arc 5 were to float upward and touch the glass tube, it could explode in the worst case.

Therefore, in this type of device, an arc correction mechanism is provided to stabilize the arc discharge 5.

As the arc correction mechanism, a magnet 8 is generally used as shown in FIG. 5, and the arc 5 is bent upward by magnetic lines of force 9 perpendicular to the current 7 flowing from the anode 4 to the cathode 3 based on Fleming's left-hand rule. It prevents This magnet 8 is attached to the F of the reflecting mirror 2 (Fig. 3).
At a position corresponding to the center of the xenon lamp 1 when facing the
They are fixed via Brague yl~10 so that the south poles are opposed in the horizontal direction perpendicular to the optical axis.

Incidentally, Fl is a force that tries to lift the arc 5 due to the convection current 6, and F2 is a force that tries to pull the arc 5 downward with the magnets 1 to 8.

[Problem to be solved by the invention] By the way, such arc correction a! When using a display device with an ellipse, it is best to project horizontally, that is, at right angles to the screen, but due to the nature of the projector, in some cases it may be projected at ±15°1 as shown in Figure 6.
It may be used by fanning it by 5 degrees (for example, 45 degrees). In this case, since the axis of the xenon lamp 1 is perpendicular to the projection axis, the arc correction magnet 8 also rotates together with the reflecting mirror 2, and is shifted from the bottom of the xenon lamp 1. Therefore, the magnitude and direction of the force that the arc 5 receives is F, and there is a problem that the arc discharge 5 becomes unstable due to the magnet 8 that is supposed to be correcting it.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to be able to always hold the magnet in a fixed position regardless of changes in the projection angle with respect to the screen, and to prevent arc discharge. An object of the present invention is to provide a stabilizing arc correction mechanism for a xenon lamp.

[Means for Solving the Problems 1] In order to achieve the above object, the present invention provides a display device in which information formed on a carrier is irradiated with a xenon lamp and projected in an enlarged manner. A roller is rotatably arranged on the edge of the hole, and an arc correction magnet is housed in the roller via a holding member.

[Operation] In the present invention, when the reflecting mirror rotates around its optical axis, the roller rotates at that position and always sets the magnet at the same position.

[Example] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 is a sectional view showing an embodiment of the arc correction mechanism for a xenon lamp according to the present invention, and FIG. 2 is a rear view of a reflecting mirror. Components that are the same as those of the conventional mechanism shown in FIGS. 3 to 6 are designated by the same reference numerals, and their explanations will be omitted. In these figures, the inner surface of the reflection M2 forms an elliptical reflection surface, and the xenon lamp 1 is disposed with its center coincident with the first focal point HP□.

Reflected light 12 emitted from the xenon run 11 and reflected by the reflecting mirror 2 hits a cold mirror 13 and is reflected, irradiates a carrier (not shown), and is enlarged and projected onto a screen.

The xenon lamp 1 is arranged horizontally so that its center line coincides with the optical axis of the reflecting mirror 2.
protruding from behind. Further, a roller 1 is provided in the hole 14.
5 are rotatably arranged. The roller 15 is made of a non-ferrous metal such as aluminum, and has a groove 16 at the center of its outer peripheral surface that engages with the edge of the hole 14, thereby preventing it from falling out of the hole 14. Further, the upper end of the holding member ]-7 is attached to the shaft 18 of the roller 15 so as to be rotatable relative to the roller. Holding member 1
The lower end of the mirror 7 is bent diagonally downward along the lower surface of the reflecting mirror 2, and holds a magnet 8 for arc correction at its tip.

In such a configuration, when the display device is rotated at an appropriate angle and the image is projected onto the screen, the xenon lamp 1 and the reflecting mirror 2 rotate according to the angle. When the reflection M2 rotates, the roller 15 also rotates along the edge of the hole 14, but its position remains unchanged. Also,
Since the holding member 17 is rotatable relative to the roller 15, it always maintains a vertical state even when the roller 15 rotates, and the magnet 8 is always positioned below the reflecting mirror 2.

Therefore, even when the display device is used tilted at a certain angle or more, disturbances in arc discharge due to convection can be corrected, and stable arc discharge can be obtained.

[Effects of the Invention] As explained above, the arc correction mechanism for a xenon lamp according to the present invention has a roller rotatably disposed in the hole provided at the rear top of the reflector, and a roller for arc correction. Since the magnet V is installed through the holding member, even when the display device is used tilted, the magnet can always be positioned below the xenon lamp, and the disturbance of arc discharge due to xenon gas convection can be effectively prevented. It can be corrected reliably. Therefore, stable arc discharge can be obtained, the life of the xenon lamp can be extended, and the structure is simple, and the installation work to the reflecting mirror can be easily performed with one touch.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the arc correction mechanism for a xenon lamp according to the present invention, FIG. 2 is a rear view of a reflector, FIG. 3 is a sectional view showing a conventional example of the arc correction mechanism, and FIG. Figures 6 to 6 are diagrams showing the convection of xenon gas and the position of the magnet. 1... Xenon lamp, 2... Reflector, 3... Cathode, 4... Anode, 5... Arc discharge, 6... Convection,
8... Magnet, 9... Lines of magnetic force, 13... Cold mirror 14... Hole, 15... - Roller, 1617
...Holding member, 18...shaft. Groove, Figure 1

Claims (1)

[Claims] In a display device that irradiates information formed on a carrier with a xenon lamp and projects it in an enlarged manner, a roller is rotatably disposed on the edge of a hole formed at the rear top of a reflector surrounding the xenon lamp, and the roller An arc correction mechanism for a xenon lamp, characterized in that an arc correction magnet is attached to the xenon lamp via a holding member.