Television – Video display – Projection device
Reexamination Certificate
2000-01-28
2003-09-23
Lee, Michael H. (Department: 2614)
Television
Video display
Projection device
C348S734000, C348S705000
Reexamination Certificate
active
06624854
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a projection image display device operated by a remote controller (referred to as a “remote control transmitter”, hereinafter). More particularly, the invention relates to a projection image display device capable of controlling a plurality of projection image displays by one remote control transmitter, and a projection image display device provided with a plurality of remote control signal receiving sections.
2. Description of the Prior Art
In exhibitions, training courses, and so on, projection image displays are used to project images on large screens. In particular, a projection image display called a liquid crystal projector is widely used as it is easily connected to a computer, VTR or the like.
The liquid crystal projector comprises a liquid crystal panel for generating an image according to a signal outputted from the computer, VTR or the like, and an optical engine for projecting the image generated by the liquid crystal panel on the screen in an enlarged manner.
FIG. 1
shows in outline an optical engine of a liquid crystal projector. A light source
50
is, for instance a metal halide lamp, and a dichroic ref lector
51
is arranged around this light source
50
. The dichroic reflector
51
orients a light emitted from the light source
50
in one direction. In the front side of a travelling direction of the light emitted from the light source
50
, a reflection mirror
52
a
is arranged at an angle of 45° to an optical axis. A UV (ultraviolet-ray)/IR (infrared-ray) cut filter
53
is arranged in the front side of an travelling direction of the light reflected by the reflection mirror
52
a
. Further down the front side from the cut filter
53
, a dichroic mirror
54
a
for separating a blue light (B), a dichroic mirror
54
b
for separating a green light (G) and a reflection mirror
52
c
are arranged all at angles of 45° to the optical axis. A reflection mirror
52
b
is arranged above the dichroic mirror
54
a
; a dichroic mirror
54
c
above the dichroic mirror
54
b
; and a dichroic mirror
54
d
above the reflection mirror
52
c
. The reflection mirror
52
b
and the dichroic mirrors
54
c
and
54
d
are respectively arranged in parallel with the dichroic mirrors
54
a
and
54
b
and the reflection mirror
52
c
. Also, a projection lens
57
is arranged in a side direction of the dichroic mirror
54
d.
A capacitor lens
55
a
and a liquid crystal panel
56
a
for a blue image are arranged between the reflection mirror
52
b
and the dichroic mirror
54
c
. A capacitor lens
55
b
and a liquid crystal panel
56
b
for a green image are arranged between the dichroic mirrors
54
b
and
54
c
, and a capacitor lens
55
c
and a liquid crystal panel
56
c
for a red image are arranged between the dichroic mirror
54
b
and the reflection mirror
52
c
. Each of the liquid crystal panels
56
a
to
56
c
has a structure, which is built by sealing in a liquid crystal between two transparent substrates: one transparent substrate including a plurality of pixel electrodes arranged in a matrix form, and the other including counter electrodes arranged oppositely to the pixel electrodes. By controlling a voltage applied between the pixel electrode and the counter electrode for each pixel, a transmitted light quantity is adjusted for each pixel to generate an image.
With the liquid crystal projector constructed in the above manner, a light emitted from the light source
50
is reflected on the reflection mirror
52
a
, and ultraviolet and infrared rays are removed from the light while passing through the filter
53
. Then, the light passed through the filter
53
is separated by the dichroic mirror
54
a
into a blue light (B) to be reflected on the mirror
54
a
and a light to transmit through the mirror
54
a
. The light reflected on the mirror
54
a
is further reflected on the reflection mirror
52
b
, and passes through the capacitor lens
55
a
to reach the liquid crystal panel
56
a
. Then, a transmittance of the blue light (B) is controlled for each pixel by means of an image signal supplied to the liquid crystal panel
56
a
, and a blue image is generated.
On the other hand, the light transmitted through the dichroic mirror
54
a
is separated by the dichroic mirror
54
b
into a green light (G) to be reflected on the dichroic mirror
54
b
and a red light (R) to transmit through the same. The green light (G) obtained by separation performed by the dichroic mirror
54
b
passes through the capacitor lens
55
b
to reach the liquid crystal panel
56
b
. Then, a transmittance of the green light (G) is controlled for each pixel by means of an image signal supplied to the liquid crystal panel
56
b
, and a green image is generated. Likewise, the red light (R) transmitted through the dichroic mirror
54
b
passes through the capacitor lens
55
c
to reach the liquid crystal panel
56
c
, and a red image is generated by means of an image signal supplied to the liquid crystal panel
56
c
. The blue image generated by the liquid crystal panel
56
a
transmits through the dichroic mirror
54
c
. By the dichroic mirror
54
c
, the blue image is synthesized with the green image generated by the liquid crystal panel
56
b
. Then, by the dichroic mirror
54
d
, the synthesized image is further synthesized with the red image generated by the liquid crystal panel
56
c
. The image synthesized in this manner is then projected through the projection lens
57
on the screen.
Usually, the liquid crystal projector can be remotely controlled on its operations including input signal switching, brightness adjustment, contrast adjustment, zooming, focusing, lamp turning ON/OFF, and so on, and operations regarding voices (volume adjustment or the like) by using a remote control transmitter.
FIG. 2
is a block diagram showing an electric circuitry of a conventional liquid crystal projector. A video signal and a synchronizing signal outputted from a computer or a video device enter a liquid crystal driving circuit
62
. The liquid crystal driving circuit
62
separates the video signal into an R signal for a red image, a G signal for a green signal and a B signal for a blue image. The driving circuit
62
supplies these R, G and B signals respectively to a liquid crystal panel (R panel)
63
a
for a red image, a liquid crystal panel (G panel)
63
b
for a green image and a liquid crystal panel (B panel)
63
c
for a blue image together with the synchronizing signal.
A control unit
61
sends a signal specifying a display starting position and a signal specifying resolution to the liquid crystal driving circuit
62
. The control unit
61
controls a digital/analog converter (abbreviated to “DAC”, hereinafter)
64
, and changes brightness and contrast. In addition, the control unit
61
also controls a character generator
65
, and displays a menu screen, a setting screen or the like by the liquid crystal driving circuit
62
. In addition, the control unit
61
controls a cooling fan
71
by a fan driving circuit
70
.
An operation panel
72
includes various operation buttons provided to be operated by a user. An IR receiving section
73
receives infrared rays transmitted from a remote control transmitter (not shown), and outputs a signal to the control unit
61
. Upon having received the signal from the IR receiving section
73
, the control unit
61
analyzes the signal, and controls each section according to the analyzing result.
FIG. 3
is a flowchart showing processing performed by the control unit
61
at the time of receiving a remote control signal.
In step S
51
, the control unit
61
monitors the presence or absence of a signal from the IR receiving section
73
. Upon having received a signal from the IR receiving section
73
, the process moves to step S
52
, where analysis of a code of the received signal starts. Then, in step S
53
, determination is made as to whether the code is normal or not. If it is determined that the code is not normal, then, the process ignores the received signal an
Fujita Masaya
Isogai Hiroyuki
Fujitsu Limited
Greer Burns & Crain Ltd.
Lee Michael H.
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