Liquid crystal projector and adjusting method thereof

• US 6,646,628 B2
• Filed: 07/30/2001
• Issued: 11/11/2003
• Est. Priority Date: 07/31/2000
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nagata, Yuji, Endo, Hiroaki, Shirochi, Yoshiki
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Dinh, Duc Q
• Application Number:
  US09/919,212
• Publication Number:
  US 20020011984A1
• Time in Patent Office: 834 Days
• Field of Search: 345/89, 345/96, 345/209, 345/690, 345/212, 345/214, 353/31, 348/744
• US Class Current: 345/96
• CPC Class Codes: H04N 2005/745 Control circuits therefor
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/312 Driving therefor driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08

Abstract

In active driving of liquid crystal panels (R, G, and B) corresponding to R, G, and B color by X shift registers (R, G, and B) and Y shift registers (R, G, and B), alternating-current driving is performed such that signals to be written to the R color and B color liquid crystal panels are opposite in polarity to a signal to be written to the G color liquid crystal panel and also Vcom voltage of each of the liquid crystal panels is adjusted to thereby reduce flicker. The Vcom voltage supplied to the B color liquid crystal panel, for example, is finely adjusted to reduce flicker of a synthetic image of the liquid crystal panels.

Claims

1. An adjusting method for a liquid crystal projector, said liquid crystal projector having a plurality of liquid crystal panels for forming a display frame by spatially combining pieces of light modulated by said plurality of liquid crystal panels with each other, said adjusting method comprising the steps of:

driving a pixel electrode of each of said liquid crystal panels by a R color signal, a G color signal and a B color signal, respectively, whose polarity is reversed in each frame;

driving an opposite electrode of each of said liquid crystal panels by a video pattern formed by line reversal and also dot line reversal to the G color liquid crystal panel opposite to the liquid crystal panel for B color and the liquid crystal panel for R color, respectively.

2. The adjusting method for a liquid crystal projector as claimed in claim 1, further comprising the step of:

adjusting a direct-current level of said video pattern signal of a B color liquid crystal panel so as to minimize a luminance variation of a synthetic image formed by spatially combining pieces of light modulated by said liquid crystal panels with each other.

3. The adjusting method for a liquid crystal projector as claimed in claim 1, further comprising the step of:

adjusting a direct-current level of said video pattern signal of a R color liquid crystal panel so as to minimize a luminance variation of a synthetic image formed by spatially combining pieces of light modulated by said liquid crystal panels with each other.

4. A liquid crystal projector with a plurality of liquid crystal panels for forming a display frame by spatially combining pieces of light modulated by said plurality of liquid crystal panels with each other, said liquid crystal projector comprising:

a driving circuit for driving a pixel electrode of each of said liquid crystal panels by a R color signal, a G color signal and a B color signal, respectively, whose polarity is reversed in each frame;

a driving circuit for driving an opposite electrode of each of said liquid crystal panels by a video pattern formed by line reversal and also dot line reversal to the C color liquid crystal panel opposite to the liquid crystal panel for B color and the liquid crystal panel for R color, respectively.

5. A liquid crystal projector as claimed in claim 4, further comprising:

an adjusting circuit for adjusting a direct-current level of said video pattern signal of a B color liquid crystal panel so as to minimize a luminance variation of a synthetic image formed by spatially combining pieces of light modulated by said liquid crystal panels with each other.

6. A liquid crystal projector as claimed in claim 4, wherein

an adjusting circuit for adjusting a direct-current level of said video Pattern signal of a R color liquid crystal panel so as to minimize a luminance variation of a synthetic image formed by spatially combining pieces of light modulated by said liquid crystal panels with each other.