IMAGE PROJECTION SYSTEM BY MEANS OF DIRECT CURRENT TYPE HIGH VOLTAGE DISCHARGE

• US 20100026726A1
• Filed: 09/28/2006
• Published: 02/04/2010
• Est. Priority Date: 09/28/2006
• Status: Abandoned Application

• Current Assignee: Phoenix Electric Co., Ltd.
• Original Assignee: Phoenix Electric Co., Ltd.
• Inventors: Fujii, Toshitaka, Nakagawa, Atsuji
• Application Number:
  US12/443,205
• Publication Number:
  US 20100026726A1
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406

Abstract

The image projection system is capable of freely adjusting a tone to suit user preferences. The system has a synchronization signal generating device that generates a synchronization signal composed of a plurality of on-off patterns in synchronism with rotation of a color filter and outputs each of predetermined power levels corresponding one-to-one with the on-off patterns to the high-pressure discharge lamp at fixed timing.

Claims

1. An image projection system comprising a DC high-intensity discharge lamp, a rotary color filter which separates a first light flux applied from the high-pressure discharge lamp into a plurality of colors, a reflective optical element which gives gradation to and performs picture signal-based modulation on a second light flux having passed through the color filter, DC lighting means for driving the high-pressure discharge lamp with a direct current, a projection lens system which projects a third light flux reflected by the optical element onto a screen, and a synchronization signal generating device which detects rotation of the color filter and generates a synchronization signal, wherein the synchronization signal generating device generates a synchronization signal composed of a plurality of on-off patterns in synchronism with rotation of the color filter and outputs each of predetermined power levels corresponding one-to-one with the on-off patterns to the high-pressure discharge lamp at fixed timing.

2. The image projection system according to claim 1, wherein a maximum value of the power levels is set to be not less than 1.1 times a minimum value of the power levels.

3. The image projection system according to claim 1, wherein electrodes of the high-pressure discharge lamp are configured such that an anode is larger in mass than a cathode.