Geometrical instruments – Gauge – Collocating
Reexamination Certificate
2000-12-12
2003-01-07
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Gauge
Collocating
C033S645000, C250S491100, C356S401000
Reexamination Certificate
active
06502324
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a method of alignment between sheet materials, which is suitably used for alignment, for example between a liquid crystal display cell and a lenticular lens, which constitute a liquid crystal display panel, a method of alignment, a substrate assembling method and an aligning apparatus.
2. Prior Art
There has been a remarkable progress in the popularization of a liquid crystal display device as an image display device used for a monitor of a personal computer and various other monitors. The liquid crystal display of this type is generally constructed in such a manner that a backlight as a sheet light source for illumination is disposed on the backside of a display panel, a liquid crystal surface having a given extent is illuminated to have uniform brightness as a whole, and thus an image formed on the liquid crystal display surface of the display panel can be visible.
The conventionally used display panel includes signal and gate lines, a TFT having an amorphous silicon layer or the like formed thereon, a color filter, and so on, all of which are laminated between two glass substrates. In such a display panel, a light emitted from the backlight is dispersed into three colors of R (Red), G(Green) and B (Blue) by the color filter to form a pixel of each of R, G and B colors.
Especially, in a projection type liquid crystal display device, the quantity of transmitted lights is increased by condensing incident lights using the lenticular lens and converging the lights to the opening portion of the pixel. The example thereof is described in Japanese Patent Laid-Open No. Hei 3-244286.
In recent years, as a technology for removing filters from the display panel, the display panel using the lenticular lens has been developed.
FIG. 12
schematically shows the structure of such a display panel using the lenticular lens. In
FIG. 12
, a reference numeral
1
denotes a liquid crystal display cell; and
2
a lenticular lens.
The liquid crystal display cell
1
includes a liquid crystal sealed in between two glass substrates
3
A and
3
B, a signal line
4
s,
a gate line (not shown), a TFT device, a display electrode, and so on. In the glass substrate
3
A, a black matrix
5
is formed to cover the signal line
4
s
and the gate line.
The lenticular lens
2
includes a number of arrayed condenser lens portions
7
formed to be roughly circular-arc in section. As shown in
FIGS. 12 and 13
, the roughly circular-arc section of each of the condenser lens portions
7
is formed to be continuous in the extended direction of the signal line
4
s.
Each condenser lens portion
7
is formed such that in the width direction thereof, totally three opening portions
8
can be positioned between joints
7
a
and
7
a
of the other condenser lens portions
7
arrayed in both sides thereof, each opening portion
8
being defined by a black matrix
5
and forming one pixel.
In such a display panel having the lenticular lens
2
, a light emitted from the backlight unit (not shown) as a light source is dispersed into three colors of R, G and B by a diffraction grating provided in the backlight unit, and the dispersed lights are made incident on the lenticular lens
2
. In this case, the incident angles of the dispersed lights are different from one another for each color, and each dispersed light is parallel rays of light. Thus, the light of each color condensed at the condenser lens portion
7
of the lenticular lens
2
forms an image at each of the three opening portions
8
arrayed between the joints
7
a
and
7
a.
As a result, the pixels of three colors, R, G and B are formed side by side in the width direction of each condenser lens portion
7
.
In the manufacturing process of such a display panel, in order to accurately align the position of each color image (light) formed by the light condensed at the condenser lens portion
7
of the lenticular lens
2
with the position of each opening portion
8
formed in the glass substrate
3
A, alignment must be performed between the lenticular lens
2
and the liquid crystal display cell
1
.
For the purpose of performing alignment between the lenticular lens
2
and the liquid crystal display cell
1
, technologies have already been disclosed in Japanese Patent Laid-Open No. Hei 8-211515 and Japanese Patent Laid-Open No. Hei 9-113215. According to the technology disclosed in Japanese Patent Laid-Open No. Hei 8-211515, a mark for alignment is formed in the lenticular lens
2
or a substrate of the opposite side thereof (liquid crystal display cell
1
), and alignment is performed by using this mark. According to Japanese Patent Laid-Open No. Hei 9-113215, a “planar area” not roughly circular-arc in section is formed in the lenticular lens
2
, and alignment is performed by viewing this planar area through a microscope.
However, in the foregoing conventional technologies, the mark for alignment must be provided in the lenticular lens
2
or the substrate, and the planar area must be formed in the lenticular lens
2
. Thus, extra time and labor for forming such a mark or a planar area were necessary.
In its manufacturing process, the lenticular lens
2
is cut out in a specified size from a web continuous in the extended direction of the condenser lens portion
7
roughly circular-arc in section. At this time, the mark for alignment or the planar area is formed in this web manufacturing stage. If the mark for alignment or the planar area is formed beforehand in the web, the position of cutting the lenticular lens
2
out of the web is decided. Thus, if some defective spots are found, the position of cutting-out cannot be shifted, thus reducing yield.
Furthermore, the lenticular lens
2
and the liquid crystal display cell I must be stuck to each other with accuracy of, e.g.,
—
25 &mgr;m in order to prevent an image quality problem. However, for the lenticular lens
2
itself, the accuracy of pitches for the condenser lens portions
7
is set equal to
—
20 &mgr;m in the manufacturing process. Thus, for this sticking, alignment between the lenticular lens
2
and the liquid crystal display cell
1
must be performed with very high accuracy of
—
5 &mgr;m.
SUMMARY OF THE INVENTION
The present invention was made with the foregoing technical problems in mind, and the object of the present invention is to provide a method of alignment between sheet materials, a method of alignment, a substrate assembling method, and an aligning apparatus, which are capable of easily and surely performing highly accurate alignment and suppressing a reduction in material yield.
In order to achieve the foregoing object, according to the present invention, a method of alignment between sheet materials comprises the steps of: setting a focus of a microscope on a first sheet material in the laminated state of first and second sheet materials to perform measurement for a position of a specified portion of the first sheet material, setting the focus of the microscope on the second sheet material to perform measurement for a position of a specified portion of the second sheet material; and performing alignment between the first and second sheet materials based on the measured positions of the first and second sheet materials.
By changing the focus of the microscope in the laminated state of the first and second sheet materials, the positions of the first and second sheet materials based on the microscope as a reference can be respectively understood.
In this case, the second sheet material may be transmissive or non-transmissive. However, brightness necessary for the position measurement at the microscope must be secured. Any order for the measurements of the specified portions of the first and second sheet materials can be employed.
If the second sheet material is a lens sheet having a plurality of lens portions arrayed side by side, the position of the lens sheet is measured at the joint of the lens portions adjacent to each other. The joint of the lens portions is sufficiently thin compared with a signal line
Colgan Evan George
Heitoh Tsuneo
Noguchi Michikazu
Suzuki Masaru
Jagan Mirellys
Scully Scott Murphy & Presser
Underweiser, Esq. Marian
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