3. OPTICAL SYSTEM

3-1. Configuration

 

No.

Name

Description

 

 

 

Light source of the optical system. AC lighting system 120W, arc length 1.3 mm.

 

1

UHP lamp

As the arc length is shorter than the conventional metal halide lamp, the light source

Lamp

operates as an ideal light point source and this improves the light convergence factor.

 

 

Also, the color temperature gets higher and this allows to reproduce more natural

unit

 

 

 

 

white color.

 

 

 

 

2

Parabolic

Parabolic reflector converges light emitted from the UHP lamp forward in approximate

 

reflector

parallel light beams and illuminates the liquid crystal panel.

 

 

 

3

UV IR filter

Optical filter to pass necessary visible rays and cut unnecessary ultraviolet rays and

 

 

infrared rays among light emitted from the UHP lamp.

 

 

 

 

4

Multi-lenses

Two multi-lenses A and B allow a circular beam light emitted from the light source to

 

illuminate the square liquid crystal panel evenly, thus providing projected pictures

 

A, B

 

 

with less brightness variation.

 

 

 

 

5

Polarization

Separates the illuminating light from the light source into P polarization light and S

 

light beam

 

polarization light and leads both light to the multi-lens B with a little angle.

 

 

splitter (PBS)

 

 

 

 

6

Phase

Converts the polarization direction of incident light via the multi-lens B into another

 

difference

direction. Here, P polarization light waveform separated by PBS is converted into

 

 

plate

another S polarization light waveform.

 

7

Condenser

Converges the illuminating light emitted from the light source into the liquid crystal

 

lens

panel.

 

 

 

 

Dichroic

Separates the white light emitted from the light source into RGB three primary colors.

 

8

The white light emitted from the light source reflects B light using a dichroic mirror 1

 

mirror

and the RG lights pass through the dichroic mirror 1. Of the RG lights passed, G light

 

 

Mirror

 

 

is reflected by the dichroic mirror 2 and R light passes.

box

9

Full reflection

Reflection mirror to lead the R and B lights separated by the dichroic mirrors 1 and 2

unit

mirror

to the liquid crystal panel.

 

 

10

Field lens

Light transmitted through liquid crystal panel is converged in direction of focal point

 

and effectively entered entrance pupil of the projection lens.

 

 

 

 

 

 

In the R axis optical path which is longer than those of G, B, the relay lens works as

 

11

Relay lens

a correction lens to arrange the illumination distribution of the liquid crystal panel

 

 

 

surface with that of other liquid crystal panel.

 

 

 

The illumination lights separated into RGB have the S polarizing waveform compo-

 

 

 

nent in processing the PBS and phase difference plate operation previously de-

 

 

 

scribed.

 

 

Incident side

The incident side polarized plate arranges the illumination light more effective direct

 

 

polarizing waveform. The phase difference plate used works to converge the S

 

12

polarized

polarizing waveform into the P polarizing waveform which fits to the transparent axis

 

plate/Phase

of the liquid crystal panel.

 

 

difference

Since the phase difference plate possesses the wavelength characteristics for light,

 

 

plate

each RGB axis employs exclusive phase difference plate. These polarizing plates

 

 

 

and difference plates are constructed in one plate by attaching each other, and put

 

 

 

on a glass plate.

 

 

 

To increase the color purity ratio of three primary colors, the glass plate possess the

 

 

 

dichroic filter characteristics for RG axis.

 

 

 

Light exit side polarized plate is put on the light exit plane. When no signal voltage is

 

 

 

applied, the polarization direction of transmission light rotates by 90 degrees. When a

 

 

 

voltage is applied, the polarization direction is controlled owing to the voltage

 

 

Liquid crystal

applied. That is, the liquid crystal panel employs such general TN type liquid crystal.

Prism

13

In this model, the incidence/exit polarization plate is placed (in normally white mode)

panel

so that the light transmission amount becomes maximum (white) when no voltage is

unit

 

 

 

added and the light transmission amount becomes minimum (black) when maximum

 

 

 

 

 

 

voltage is added.

 

 

 

According to the liquid crystal panel specification, exclusive panel for each RGB axis

 

 

 

is employed and shown by identification seals.

 

14

Cross prism

Works to mix RGB lights passed through the liquid crystal panel.

 

 

 

Demodulated by the video signal on the liquid crystal panel and projects pictures

 

 

 

displayed on the liquid crystal at a screen. Light axis of the projection lens is set at

Projec-

 

Projection

upper side of center of the liquid crystal panel and this realizes easy viewing of the

15

panel because the projected screen position is upper than the unit position. The

tion

lens

projected light shows S polarizing waveform and is compatible with the polarizing

lens

 

 

 

screen.

 

 

 

 

 

 

The projection lens employs the zoom & focus system and allows to project enlarging

 

 

 

a picture upto maximum approx. 300 inch.

 

 

 

 

3-1

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Toshiba TLP510U, TLP511E, TLP510E, TLP511U manual Optical System, Name Description