Browse Prior Art Database

High Brightness Color Liquid Crystal Display Projector

IP.com Disclosure Number: IPCOM000119170D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 111K

Publishing Venue

IBM

Related People

Ishikawa, M: AUTHOR [+2]

Abstract

Disclosed is a high brightness color Liquid Crystal Display (LCD) projector which reuses the non-selected polarized light without an additional polarizing beam splitter. The projector optics comprises: 1. a lamp 2. a reflector 3. a collimator lens 4. a quarter wave plate 5. a polarizing beam splitter 6. a green transmitting (red and blue reflecting) dichroic mirror 7. the first reflecting type LCD panel 8. a blue reflecting (red and green transmitting) dichroic mirror 9. the second reflecting type Liquid Crystal Display panel 10. red transmitting (green reflecting) dichroic mirror 11. the third reflecting type LCD panel, and 12. a projection lens (Fig. 1).

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High Brightness Color Liquid Crystal Display Projector

      Disclosed is a high brightness color Liquid Crystal Display
(LCD) projector which reuses the non-selected polarized light without
an additional polarizing beam splitter.  The projector optics
comprises:
   1.  a lamp
   2.  a reflector
   3.  a collimator lens
   4.  a quarter wave plate
   5.  a polarizing beam splitter
   6.  a green transmitting (red and blue reflecting) dichroic mirror
   7.  the first reflecting type LCD panel
   8.  a blue reflecting (red and green transmitting) dichroic mirror
   9.  the second reflecting type Liquid Crystal Display panel
  10.  red transmitting (green reflecting) dichroic mirror
  11.  the third reflecting type LCD panel, and
  12.  a projection lens (Fig. 1).

      The randomly-polarized light emitted from the lamp (1), such as
a metal halide lamp, is reflected by the spherical reflector (2) and
focuses on the center of the lamp.  The focused light and directly
emitted light are collimated by the collimator lens (3).  The
collimated beam goes through the quarter (4).  But, because the
incident beam is randomly-polarized, the transmitted beam is still a
randomly polarized  beam, too.  The beam is then split into two
linearly polarized beams by  the Polarized Beam Splitter (PBS) (5).
The p-polarized component, which  transmits through the PBS, is then
split into two beams by the green transmitting dichroic mirror (6).
The Green and P-polarized component  (GP) which transmits the
dichroic mirror is reflected by the first LCD  panel, and its
polarization direction is modulated by an LCD panel according to the
electrical signal applied to the LCD panel. Modulated  light is
s-polarized light and reflected by a PBS.  The reflected light  is
projected onto the screen by a projection lens (12).  The red (RP)
and blue (BP) components are reflected by the dichroic mirror (6) and
returns to the PBS.  The s-polarized component, which is reflected by
the PBS,  is also split into two beams by the blue reflecting
dichroic mirror (8).  The Blue and S-polarized component (BS) are
reflected by the second  LCD panel (9) and its polarization direction
is modulated by the LCD panel according to the electrical signal
applied to the LCD panel. The  modulated light is p-polarized light
and is reflected by a dichroic mirror (8) which transmits PBS.  The
transmitting light is projected onto  the screen by a projection lens
(12).  The s-polarized red and green components which transmit the
dichroic mirror (8) are separated into two  beams by the red
transmitting dichroic mirror (10).  The S-polarized Red  component
(RS) which transmit the dichroic mirror (10) is reflected by  the
third LCD panel (11...