Ballast and projector

A ballast and trigger technology, applied in the field of projectors, can solve problems such as slow rise in electrode temperature, increased insulation tolerance, poor lighting, etc.

Inactive Publication Date: 2006-12-13
SEIKO EPSON CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, at the time of next lighting, since the position of the glow discharge is not determined by the output of the normal flip-flop circuit, the electrode temperature rises slowly, and the mercury cannot be vaporized, resulting in poor lighting.
In addition, in the high-pressure discharge lamp of the system in which the output of the flip-flop circuit is supplied to only one electrode, there is a problem that the insulation resistance around the one electrode must be increased.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0023] figure 1 It is a circuit diagram of the ballast according to Embodiment 1 of the present invention. The ballast is composed of a rectifier circuit 2 for rectifying the AC power source 1, an inverter 3, a trigger transformer 4, a trigger transformer drive circuit 5, and a control unit 6. The output terminal of the trigger transformer 4 is connected to a high-pressure discharge lamp 7 . The rectifier circuit 2 is composed of an inductor L1, a switching element S1, and a diode D. As shown in FIG. The inverter 3 is composed of four switching elements S2-S5 that are fully bridged. The switching elements S2, S5 and S4, S3, through alternate conduction control, convert the DC voltage from the rectifier circuit 2 into an AC voltage, and output it to Trigger Transformer4. The trigger transformer 4 outputs a high voltage to the high pressure discharge lamp 7 as will be described later. The high-pressure discharge lamp 7 is a reflective light source device, and the luminous tu...

Embodiment approach 2

[0029] Figure 4 It is a circuit diagram of the flip-flop transformer 4 according to Embodiment 2 of the present invention. The trigger transformer 4 is composed of two trigger transformers 4a and 4b. When the excitation current is supplied to the respective primary coils T1a and T1b under the control of the trigger transformer drive circuit 5, the secondary coils T2 and T3 can obtain and image 3 The waveforms shown are the same as the output voltage.

Embodiment approach 3

[0031] Figure 5 It is a configuration diagram of an optical system of a projector incorporating the ballasts of Embodiments 1 and 2 described above in an illumination optical system. in addition, Figure 5 The Ballast 10 includes figure 1 The rectifier circuit 2, the inverter 3, the trigger transformer 4, the trigger transformer drive circuit 5, and the control unit 6 make the high-pressure discharge lamp 7 of the illumination optical system 100 light as described above, thereby preventing the In some cases, the lighting failure of the high-pressure discharge lamp may occur.

[0032] The projector has: an illumination optical system 100, dichroic mirrors 210, 212, reflection mirrors 220, 222, 224, an incident side lens 230, a relay lens 232, three field lenses 240, 242, 244, three liquid crystal panels 250, 252 , 254 , polarizers 251 , 253 , 255 , 256 , 257 , and 258 , cross dichroic prism 260 , and projection lens 270 respectively disposed on the output side and incident ...

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PUM

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Abstract

The present invention provides a ballast capable of eliminating lighting failures and reducing insulation resistance, and a projector equipped with the ballast. The ballast has a trigger transformer (4), and a trigger transformer drive circuit (5) that supplies an excitation current to the primary coil of the trigger transformer (4) at the start of lighting, and the trigger transformer (4) supplies the high-pressure discharge lamp The electrode (73) (base end electrode) and electrode (75) (front end electrode) of (7) apply the opposite voltage of polarity, and, make the absolute value of the voltage applied on the electrode (75) be greater than that applied to the electrode (73) ) the absolute value of the voltage on.

Description

technical field [0001] The present invention relates to a ballast for lighting a high-pressure discharge lamp such as a high-pressure mercury lamp or a metal halide lamp, and a projector incorporating the ballast. Background technique [0002] There is a trigger circuit in the ballast of the prior art. When lighting, generally the output of the left-right symmetrical trigger circuit is applied to the two electrodes of the high-pressure discharge lamp, or the output of the trigger circuit is applied to the high voltage A high-pressure discharge lamp is turned on on one electrode of the discharge lamp (for example, refer to Patent Documents 1 and 2). [0003] [Patent Document 1] JP-A-2003-316440 [0004] [Patent Document 2] JP-A-2003-151786 [0005] However, due to the structure of the high-pressure discharge lamp, when the lamp is turned off after lighting, the cooling of the left and right electrodes becomes unbalanced. This cooling imbalance causes more of the enclosed m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B41/14H01F38/10
CPCH05B41/288
Inventor 大川一夫
Owner SEIKO EPSON CORP
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