Liquid crystal cells – elements and systems – Particular structure – Particular illumination
Reexamination Certificate
2002-04-23
2004-08-31
Nguyen, Dung T. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Particular illumination
C349S113000, C349S095000
Reexamination Certificate
active
06784952
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reflection type semiconductor display device of a direct viewing type, and more particularly, to a reflection type liquid crystal display device (liquid crystal panel). The present invention also relates to a semiconductor device with a reflection type liquid crystal display device mounted thereon.
A semiconductor device as referred to in the present invention may be, for example, information processing equipment such as a notebook-sized personal computer, a lap top type personal computer, an electronic notebook, or a mobile computer, a video camera, a digital still camera, a car navigation system, or a cellular telephone.
2. Description of the Related Art
Recently, an intensive study and development have been carried out with regard to manufacturing technology of liquid crystal panels to make it possible to provide liquid crystal panels at a relatively low cost. Further, as the information society where Internet, electronic mail, and the like are utilized has been developed, notebook-sized personal computers (hereinafter abbreviated as notebook-sized PCs) have rapidly become more popular.
With regard to digital still cameras and video cameras, as they have been allowed to have liquid crystal panels mounted thereon such that images taken can be viewed on the spot, they have become widely accepted by consumers.
Liquid crystal panels fall into transmission type ones and reflection type ones. In a transmission type liquid crystal panel, illumination light is transmitted through the liquid crystal panel from a back light provided at the back so that the user can visually confirm the display. On the other hand, a reflection type liquid crystal panel does not need a back light, and the display can be seen through reflection of external light on the liquid crystal panel. Such a back light consumes about 90% of power consumption of the transmission type liquid crystal panel, and thus, power consumption of a transmission type liquid crystal panel is large. On the other hand, though the display quality level of a reflection type liquid crystal panel is inferior to that of a transmission type liquid crystal panel, power consumption of a reflection type liquid crystal panel is smaller than that of a transmission type liquid crystal panel, and thus, a reflection type liquid crystal panel is advantageous when used in a notebook-sized PC or a mobile PC.
One reason of the inferiority of the display quality level of a reflection type liquid crystal panel to that of a transmission type liquid crystal panel could be the insufficient amount of light when it is used indoors.
These days, in order to solve the problem of the insufficient amount of light, a technique to provide a reflection type liquid crystal panel with a front light is adopted to supplement insufficient amount of light when it is used indoors. However, in this case, since a fluorescent lamp similar to that used as a back light of a transmission type liquid crystal panel is used as the front light, leading to larger power consumption, the advantage of a reflection type liquid crystal panel cannot be obtained.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made in view of the above problem, and an object of the invention is to provide a reflection type semiconductor display device having high display quality level without insufficiency of the amount of light even when it is used indoors.
In order to solve the above problem, according to the present invention, light other than incident light on a liquid crystal panel is utilized as an auxiliary light source of a reflection type semiconductor display device.
FIG. 1
shows a schematic structural view of a reflection type semiconductor display device using a reflection type liquid crystal panel according to the present invention. Reference numerals
101
,
102
, and
103
denote a main body, a reflection type liquid crystal panel, and an optical fiber array, respectively. The optical fiber array
103
includes a plurality of optical fiber cables
104
. Each of the optical fiber cables
104
is a bundle of a plurality of optical fibers, examples thereof being shown in
FIGS. 2A and 2B
. The optical fiber array is used as means for taking in external light.
In
FIGS. 2A and 2B
, reference numeral
201
denotes an optical fiber, an enlargement thereof being shown at the lower portion in
FIGS. 2A and 2B
. The optical fiber
201
has a core and a clad. The index of refraction of the core is larger than that of the clad, and light travels as it repeats total internal reflections at the interface between the core and the clad. A coating
202
is formed of a resin or the like. A reinforcing material
203
is formed of a resin or the like.
It is to be noted that, in the optical fiber cable
104
shown in
FIG. 2A
, a bundle of tightly packed optical fibers is covered with the coating
202
. Further, in the optical fiber cable
104
shown in
FIG. 2B
, the reinforcing material
203
fills the space among the optical fibers to improve the strength.
Next, reference is made to FIG.
3
.
FIG. 3
shows a sectional view of a reflection type liquid crystal panel according to the present invention. Reference numeral
301
denotes a substrate. Reference numerals
302
and
303
denote driver TFTs (thin film transistors). Reference numerals
304
,
305
,
306
, and
307
denote a pixel TFT, a reflection electrode, liquid crystal, and a counter substrate, respectively. It is to be noted that the pixel TFT can be made of amorphous semiconductor film or polycrystalline semiconductor film. Also it is to be noted that a transparent electrode (not shown) is provided under the counter substrate.
The optical fiber cables
104
are positioned such that light taken in from one end of each of the optical fiber cables
104
is emitted from the other end thereof to the counter substrate. Consequently, incident light entered into the optical fiber cables travels through the optical fibers, enters the counter substrate
307
, traveling through the counter substrate
307
, and then enters the liquid crystal. It is to be noted that the upper surface of the counter substrate
307
is appropriately processed to allow incident light on the liquid crystal by eliminating the requirement for the total internal reflections of light traveling through the substrate at the interface. The processing condition can be most suitably set through simulation or the like. In
FIG. 3
, the upper surface of the counter substrate
307
is formed with patterns, but the present invention is not limited thereto.
Alternatively, as shown in
FIG. 4
, the panel may be structured to use a counter substrate used in a general reflection type liquid crystal panel and a light guide plate
408
. Reference numeral
401
denotes a substrate. Reference numerals
402
and
403
denote driver TFTs. Reference numerals
404
,
405
,
406
, and
407
denote a pixel TFT, a reflection electrode, liquid crystal, and a counter substrate, respectively. In this case, the upper surface of the light guide plate
408
is processed so as to eliminate the requirement for the total internal reflections of incident light traveling through the light guide plate
408
at the interface.
It is to be noted that any suitable means may be used to allow incident light taken in by the optical fiber cables
104
to travel through the counter substrate or the light guide plate into the liquid crystal.
The present invention will be described in view of the structure.
According to the present invention, there is provided a reflection type semiconductor display device in which light emitted from one end of an optical fiber enters said reflection type semiconductor display device, wherein the light is external light taken in from the other end of the optical fiber.
Further, according to the present invention, there is provided a reflection type semiconductor display device in which light emitted from one end of an optical fiber enters a counter substrate of said reflection type s
Cook Alex McFarron Manzo Cummings & Mehler, Ltd.
Nguyen Dung T.
Qi Mike
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