JP3257555B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape carrier package for driving a liquid crystal used in a liquid crystal display device (hereinafter referred to as a TCP (Tape Carrier Package) for a liquid crystal driver).
In particular, a liquid crystal suitable for a notebook personal computer (hereinafter, referred to as a notebook PC), a word processor (hereinafter, referred to as a word processor), and the like, which is small, light, thin, and requires low power consumption and has excellent portability. It relates to TCP for drivers.

[0002]

2. Description of the Related Art At present, two thirds of a laptop personal computer (hereinafter referred to as a laptop PC).
Are notebook PCs with excellent portability, and in a few years, all of the laptop PCs are going to become notebook PCs.

A liquid crystal driver T suitable for this notebook PC
As a CP, a narrow TCP type mounting a slender string-like liquid crystal driving LSI chip having an 80-channel output or a 160-channel output, that is, a so-called slim TCP or a micro TCP (hereinafter referred to as a micro TCP) TCP for a liquid crystal driver. Has been proposed. Further, in this method, the bump pitch of the LSI chip is adjusted to the outer lead pitch width as much as possible to reduce the bent portion on the tape pattern.

However, when the outer lead pitch width is set to LSI
In order to match the bump pitch of the chip,
It is obvious that the aspect ratio of the LSI chip is increased and various measures are required to relax the stress on the LSI chip during inner lead bonding.

[0005] By mounting such a micro TCP on a liquid crystal element, it is possible to reduce a portion around the liquid crystal element, that is, a portion called a frame (hereinafter, referred to as a frame), and to reduce the size of the liquid crystal module. , Thinner and lighter weight can be achieved.

However, from the viewpoint of reducing the cost of the liquid crystal module for notebook PCs, these proposed micro TCPs cannot yet meet the market requirements in terms of cost.

Further, the reliability of the liquid crystal module after the micro TCP is mounted on the liquid crystal panel,
The stress concentration on the inner lead and the input-side outer lead increases as much as the P width decreases, and disconnection or the like occurs.

[0008]

The above prior art is based on LS
I-chip production yield, TCP tape production yield and T
Micro T, such as yield of mounting LSI chip on CP tape
No consideration has been given to achieving high yield and high reliability in the CP production yield, and in terms of reducing the cost of the micro TCP, and eventually reducing the cost and the reliability of the liquid crystal module and the notebook PC itself. Even had limitations.

An object of the present invention is to use a conventional liquid crystal driver LSI chip which can be manufactured at a high yield in view of the LSI chip manufacturing yield and the total yield of TCP.
The distance from the chip to the outer lead on the output side is set to a length that can be bent using a large diameter tube such as a cold cathode tube for backlight, etc.
Achieving P.

Further, by applying the liquid crystal driver TCP to a liquid crystal module, the frame can be reduced.
An object of the present invention is to reduce the size, weight, thickness, and cost of a notebook PC.

[0011]

An object of the present invention is to use a large-diameter cold-cathode tube or the like used for a so-called edge-light type backlight in which a light source such as a cold-cathode tube is arranged on the side surface of a light guide. By using a structure in which the liquid crystal driver TCP is bent and used (hereinafter referred to as a bent TCP), a high-yield and highly-reliable bent TCP can be achieved. In addition, by applying this bent TCP, reliability is improved. A liquid crystal module having a small frame with high flexibility can be achieved.

The terminal portion of a liquid crystal element (a typical length is about 3
A light source of a backlight (a typical tube diameter is about 3 to 4 mm) is arranged under the light guide plate, and a TCP for a liquid crystal driver is arranged under the light guide plate along a large curvature of the light source, thereby forming a bent portion. Bending stress can be minimized. In addition, since the bending stress of the liquid crystal driver TCP is minimized and arranged below the light guide plate, the frame can be minimized with high reliability.

As described above, by folding the TCP for the liquid crystal driver by using a tube diameter (about 3 to 4 mm) of a cold cathode tube or the like having a large curvature, a frame generated around the display portion of the liquid crystal display element is formed. Can be made equal to or less than the terminal portion of

By using the folded TCP of the present invention, a liquid crystal module with a small frame can be achieved, and a small and lightweight notebook PC can be achieved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal display device using a tape carrier package type liquid crystal driving LSI suitable for carrying out the present invention will be described in detail with reference to the drawings.

Tape carrier package type liquid crystal driving L
SI is TA using a tape wired with a copper foil pattern.
B (Tape Automated Bonding) technology, L for driving liquid crystal
This is the one on which the SI chip is mounted.

First, the appearance and structure of the tape carrier package type liquid crystal driver of the present invention will be described in detail with reference to FIGS. FIG. 1 shows its appearance, and FIG. 2 shows its cross-sectional structure.

FIG. 1 is an external view of a tape carrier package type liquid crystal driver of the present invention. In the figure, 1 is a base tape, 2 is an LSI chip, 3 is an output outer lead, 4 is an input outer lead, 5 is an output wiring, 6
Is an input side wiring, 7 is an inner lead, 8 is a device hole, 9 is an input outer lead hole, 10 is a solder resist, and 11 is a sprocket hole (or perforation).

As shown in FIG.
Patterns were arranged on a polyimide film having a width of 12 mm at a pitch of 12 perforations. The outer lead portions 3 and 4 were arranged in a pattern so as to be perpendicular to the sprocket hole 11. That is, since a particularly large stress is applied to the vicinity of the sprocket hole portion 11 at the time of manufacturing the tape carrier, the outer lead portion 3 requiring high dimensional accuracy is required.
By arranging the outer lead portions 4 in the direction different from the stress direction without arranging the outer lead portions 4 in the vicinity of the sprocket hole portion 11, the cumulative dimensional tolerance of the outer lead portions 3 and 4 is minimized.

FIG. 2 shows a sectional structure of a TCP for a liquid crystal driver according to the present invention. In the figure, 1 is a base tape, 2 is an LSI chip, 3 is an output outer lead, 4 is an input outer lead, 5 is an output wiring, 6 is an input wiring, 7 is an input wiring.
Is the inner lead, 9 is the input outer lead hole,
10 is a solder resist, 12 is an adhesive, 13 is a bump,
14 is a sealant.

As shown in FIG. 1, the TCP for a liquid crystal driver of the present invention has a three-layer structure, that is, a structure comprising a base tape 1 / adhesive 12 / copper foil patterns 3, 4, 5, 6, and 7.

The TCP for a liquid crystal driver of the present invention is a structure of a different material, and there are several combinations. In this embodiment, a 75 μm-thick polyimide-based film (Kapton V, Upilex S, SS) is used for the base tape 1, and an epoxy-based adhesive, wiring materials 3, 4, and 4 are used for the adhesive 12. Copper foil (rolled copper foil, electrolytic copper foil) of 35 μm thickness as 5, 6, 7; epoxy resin as sealing material 14; epoxy solder resist, outer lead etc. for solder resist 10; Solder plating was used for plating 6 and 7.

In this embodiment, the outer leads 3, etc.
Solder plating was used for 4, 5, 6, 7 plating,
There are tin plating and gold plating, etc., which should be determined in consideration of the wiring pitch of the outer leads 3, 4, 5, 6, 7, and the reliability such as chemical migration.

In this embodiment, a three-layer structure, ie, base tape 1 / adhesive 12 / copper foil patterns 3, 4, 5,
Although a tape having a structure of 6,7 is used, but a tape having a two-layer structure without using the adhesive 12, that is, a tape having a structure of base tape 1 / copper foil pattern 3,4,5,6,7, can be used to achieve dimensional accuracy. It is self-evident that the reliability is improved.

FIG. 3 shows the structure of a color liquid crystal module using the liquid crystal driver TCP of the present invention. 2, reference numeral 2 denotes a liquid crystal driver LSI chip, 18 denotes a liquid crystal display panel, 19 denotes a bent TCP of the present invention, 20 denotes a printed board, 21 denotes a cold cathode tube, 22 denotes a light guide (or light guide plate), and 23 denotes reflection. Reference numeral 24 denotes a diffusion sheet, 25 denotes a lamp reflection sheet, 26 denotes a double-sided adhesive tape, 27 denotes a lamp guide, and 28 denotes a white reflection film. In the figure, a super TN color liquid crystal panel is used for the liquid crystal panel 18, and the backlight is a 3 mm thick acrylic plate for the cold cathode tube 21, a 3 mm thick acrylic plate for the light guide or light guide plate 22, and a thickness for the reflective sheet 23. A 0.1125 mm polyester sheet, a 0.1 mm thick polyester sheet on the diffusion sheet 24, a 0.125 mm thick polyester sheet with silver vapor deposited on the lamp reflection sheet 25, and a double-sided adhesive tape 26 Is a non-woven fabric with an acrylic adhesive, lamp guide 2
7 was made of silicon rubber, and the white reflective film 28 was made of a polyester ink containing titanium oxide as a main component, or an acrylic ink containing titanium oxide as a main component.

As shown in the figure, the liquid crystal driver TCP 19 of the present invention is arranged under the light guide or the light guide plate 22 by utilizing the large radius of curvature of the cold cathode tube 21.
Since the stress applied to the inner leads of the TCP 19 can be minimized, the frame size can be reduced, and a highly reliable liquid crystal module can be achieved.

In order to minimize the stress applied to the inner leads of the liquid crystal driver TCP 19,
The solder resist in the bent portion of the liquid crystal driver TCP 19 was not formed on the entire surface, but was arranged in stripes at a specific pitch in parallel with the cold cathode tubes.

As another embodiment for minimizing the stress applied to the inner leads of the liquid crystal driver TCP 19, the base tape 1 and the copper foils 3, 4, 5,
There is a method of reducing the thickness of 6, 7. In this method, it is necessary to reinforce the sprocket holes by backing them with copper foil or to improve the mechanical strength by alloying the copper foil.

As shown in the figure, the liquid crystal driver TCP 19 of the present invention is bent under the backlight by utilizing the diameter of the cold cathode tube 21, and is arranged below the backlight. It was mounted with a width of about 5 mm. Further, a thin backlight comprising the liquid crystal panel 18, the cold cathode tube 21, the light guide 22 and the like were integrated by a metal frame having a thickness of 0.5 mm. With this configuration, the module thickness is about 8 mm, the module weight is about 500 g, and the power consumption is about 4 W
Of the notebook PC color liquid crystal module.

FIG. 4 shows a TCP 19 for a liquid crystal driver according to the present invention.
1 shows a configuration of a color liquid crystal panel for a notebook PC using the same. The liquid crystal panel 18 shown in FIG.
3) x 400 dots (pixel pitch: 0.27mm x 0.27m
m, pixel size: 0.255 mm x 0.255 mm, screen diagonal size: 8.0 inches), upper and lower electrode substrates (material: soda-lime glass, thickness: 0.2 mm)
7 mm) 131, 132, liquid crystal 140, birefringent film (Nitto Denko: uniaxially stretched polycarbonate film) 1
21, upper and lower polarizers (Nitto Denko: G1220DU, transmittance: 40%) 111,112. The lower electrode substrate 132 has a black matrix (pigment type, thickness: 0.7).
１1.3 μm) 137, color filter (pigment type, thickness: 1.5 to 2.5 μm) 138, smoothing film (epoxy resin, thickness: 0.7 to 1.3 μm) 139, lower transparent Electrode (ITO, sheet resistance: 15Ω / □) 133, alignment film (polyimide resin, thickness: 0.07 to 0.13 μm) 1
On the other hand, an upper transparent electrode (ITO, sheet resistance: 15Ω / □) 13 is formed on the upper electrode substrate 131.
4, insulating film (film material: SiO ₂ , thickness: 0.07 to 0.13)
μm) 135 and an alignment film 136 are formed.

The alignment film 136 on the upper and lower electrode substrates 131 and 132 is subjected to a rubbing process, and
Liquid crystal (Merck mixed liquid crystal, liquid crystal layer thickness: 6μ)
m) A spiral structure was formed in which 140 was twisted 260 degrees.

Further, on the opposite side of the lower electrode substrate 132 where the color filter 138 is formed, the birefringent film 12 is formed.
1, lower polarizing plate 112, upper electrode 1 of upper electrode substrate 131
An upper polarizing plate 111 was disposed on the side opposite to the side where 34 was formed.
Although FIG. 2 shows a configuration in which a color filter is formed on the lower electrode substrate 132 having a small number of electrodes for ease of electrode formation, a color filter is formed on the upper electrode substrate in consideration of ease of liquid crystal panel assembly. Is advantageous.

The liquid crystal panel 18 and the thin, low power consumption backlight 30 are constituted. This backlight 3
Light guide plate (material: acrylic, thickness: 3m)
m) 22, cold cathode tube (Matsushita: K-C240T4E7)
2, tube diameter: 4mm) 21, reflective sheet (diafoil:
W-400, thickness: 0.125 mm 23, diffuser sheet (made by Kimoto: D-204, thickness: 0.1 mm) 24, reflector sheet for lamp (made by Kimoto: GR-38W, thickness: 0.1 mm)
1mm) 25, double-sided adhesive tape (Nitto Denko: No. 50)
0) 26, a lamp guide (silicon rubber) 27, and a white reflective film (dispersant: titanium oxide, base material: polyester resin) 28.

A pigment-dispersed black matrix (width: 25 μm) 137 formed by photolithography is disposed on the lower electrode substrate 112 at a pitch of 90 μm, and a pigment-dispersed color matrix formed by printing is formed thereon. Filter 138 was placed.

The color filter 138 is formed by dispersing an organic pigment or an inorganic pigment in a melamine epoxy resin, and has a film thickness set in a range of 1.5 μm to 2.5 μm. Also, the black matrix 137
Is mainly obtained by dispersing carbon in an acrylic resin, and has a thickness of 0.7 μm to reduce the transmittance to 2% or less.
The one set in the range of 1.3 μm was used.

The pigment type black matrix 13
7, the conventional chromium (film thickness: 0.1)
As compared with a color liquid crystal display device using a black matrix formed with a thickness of about μm, a large reduction in surface reflected light can be achieved.

In this embodiment, the color filter 138 is used.
Are formed under the lower substrate side transparent electrode 134 by a printing method because of the advantage of forming the electrodes 133 and 134, and the black matrix is formed by a photolithography method. However, in order to provide an inexpensive color liquid crystal panel, the printing method is used. It is desirable to form a black matrix by the following.

In order to form a black matrix by a printing method, it is necessary to form a high-precision alignment mark or obtain an equivalent mark on the mark so as to obtain an overlay accuracy with a lower electrode formed on a color filter. It is necessary to devise such a method as to obtain the accuracy. That is, when a color filter is formed on the lower electrode side, the alignment mark,
Another important point is the alignment between the color filter formed below the lower electrode and the upper electrode. In this regard, if a color filter is formed below the upper electrode, the alignment between the lower electrode and the upper electrode becomes easier.

In the color liquid crystal display device of the present invention, the thickness of the liquid crystal layer and its uniformity are important factors that affect the display characteristics of brightness, contrast, and color range.
In order to make the thickness of the liquid crystal layer uniform, it is desirable to form a color filter with the same smoothness as the upper and lower electrode substrates.

In the color liquid crystal display device of the present invention, the dispersion amount of the pigment or the spectral transmittance characteristic of the color filter is specified so that the three characteristics of the color filter, namely, the smoothness, the color purity and the transmittance, are satisfied in a well-balanced manner. By doing so, it is possible to use a backlight having a configuration in which a fluorescent discharge tube is arranged on the side surface of the light guide, thereby achieving a reduction in thickness, weight, and power consumption.

In the color liquid crystal display device of the present invention, the point of the pigment dispersion type color filter 138 formed by this printing method is a point, and the smoothness, color purity, transmittance and the balance of these three characteristics on the color filter 138 are balanced. In consideration of,
Through experiments, the amount of pigment dispersion in the color filter was optimized.

FIG. 5 shows the relationship between the dispersion amount of the pigment and the transmittance, contrast ratio, and stimulus purity. As shown in the figure,
If the lower limits of the transmittance, the contrast ratio and the stimulus purity are respectively set to T = 5%, Cr = 10, Pr = 10%,
The range of the pigment dispersion amount satisfying all three characteristics is approximately 25
It has been found that the setting should be made in the range of% to 5%. However, the thickness of the color filter at this time is approximately 1.5 μm.
It is important to specify within the range of .about.2.5 .mu.m. That is, the spectral transmittance characteristic of the color filter is determined substantially by the product of the amount of dispersion of the pigment and the film thickness of the color filter.

In consideration of the balance between the three display characteristics of brightness, contrast, and color specification range, the thickness of the module, and the power consumption, the dispersion amount of the pigment is preferably 23% to 8%.
%, The color filter film thickness is approximately 1.7 μm to 2.
It turned out that it is sufficient to specify the range of 3 μm. Therefore,
In this embodiment, a color filter 138 having a pigment dispersion amount of about 15% is provided.

FIG. 6 shows the spectral transmittance characteristics of the color filter 138, in which the dispersion amount of the pigment is approximately 15% and the film thickness of the color filter is approximately 2 μm, and the pigment dispersion used in the conventional laptop personal computer. The dispersion amount is approximately 30%, and the thickness of the color filter is approximately 2 μm. In the figure, 410 and 411 are red spectral characteristics, and 420 and 421.
Indicates the spectral characteristics of green, and 430 and 431 indicate the spectral characteristics of blue.
Color filters identified as 5%, 411, 421, 43
Reference numeral 1 denotes a color filter in which the amount of pigment dispersion is specified to be about 30%. As shown in the figure, the transmittance in a wavelength region other than the intended color is increased, contrary to the conventional one, to improve the transmittance of the color filter and to improve the smoothness of the color filter as compared with the conventional one. The point is that it has been improved about three times.

However, the stimulus purity of the color filter of the present invention is slightly lower than that of a color filter having a pigment dispersion of about 30% used in a conventional laptop personal computer. Therefore, the color filter of the present invention is a light color filter as compared with the conventional color filter.

In order to use such a light color filter, the white balance using only the color filters or the white / black balance in the combination of the liquid crystal panel 18 and the backlight 30 in the module configuration shown in FIG. It is important to make the spectral transmittance characteristics in consideration of the following.

As described above, by combining the liquid crystal driver TCP of the present invention with a liquid crystal panel using a light color filter, a small, light, and low power consumption color liquid crystal module can be achieved.

[0048]

According to the present invention, a highly reliable bending T
CP can be achieved, and by applying the bent TCP of the present invention, the frame of the liquid crystal display can be minimized, and a small, highly portable
There is an effect that OA equipment such as a lightweight and thin word processor, a notebook PC, etc. can be achieved.

[Brief description of the drawings]

FIG. 1 is an external view of a liquid crystal driver TCP according to the present invention.

FIG. 2 is a sectional structural view of a TCP for a liquid crystal driver of the present invention.

FIG. 3 is a configuration diagram of a liquid crystal module using the liquid crystal driver TCP of the present invention.

4 is a sectional structural view of the color liquid crystal panel shown in FIG.

5 is a diagram showing the relationship among the transmittance, contrast ratio, and stimulus purity of a pigment dispersion panel of a color filter used in the color liquid crystal panel shown in FIG.

FIG. 6 is a spectral transmittance characteristic diagram of a color filter used in the color liquid crystal panel shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base tape, 2 ... LSI chip, 3 ... Output side outer lead, 4 ... Input side outer lead, 5 ... Output side wiring, 6 ... Input side wiring, 7 ... Inner lead, 8 ... Device hole, 9 ... Outer lead Hole, 10: solder resist, 11: sprocket hole, 12: adhesive, 1
3 ... Bump, 14 ... Sealant, 18 ... Liquid crystal panel, 19 ...
TCP for liquid crystal driver, 20: printed board, 21: cold cathode tube, 22: light guide plate or light guide, 23: reflection sheet, 24: diffusion sheet, 25: reflection sheet for lamp, 2
6: double-sided adhesive tape, 27: lamp guide, 28: white reflective film, 30: backlight.

Continuation of front page (72) Inventor Ken Saito 3300 Hayano Mobara-shi, Chiba Electronic Device Division, Hitachi, Ltd. (56) References JP-A-64-28621 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) G02F 1/1345 G02F 1/13357 H05K 1/14 H05K 1/18 H05K 3/36

Claims (2)

(57) [Claims] 1. A liquid crystal display panel, a light guide, and a light guide
In a liquid crystal display device having a light source arranged on a side surface, a device hole for mounting a semiconductor integrated circuit element, an organic insulating tape having a width of 35 mm or more having a plurality of sprocket holes, and affixed to the organic insulating tape, output side, and a metal thin film on which a wiring pattern having the input-side outer leads are formed, the input-side outer lead and the output side outer lead relative to the sprocket holes arrangement direction provided in the organic insulating tape The length of the outer lead on the output side is longer than the length of the outer lead on the input side from the end of the semiconductor integrated circuit element so as to reduce the diameter of the light source.
The liquid crystal display device characterized by using the liquid crystal drivers tape carrier package constructed as bent in use. 2. A liquid crystal display device having a light source disposed on one or both side surfaces of a light guide, wherein the light source is covered by a reflective sheet having a curved shape, and one surface of the light guide has A liquid crystal display panel is arranged, and on the other surface of the light guide, a device hole for mounting a semiconductor integrated circuit element, an organic insulating tape having a width of 35 mm or more having a plurality of sprocket holes, and affixed to the organic insulating tape. is, the output side of the semiconductor integrated circuit device, and a metal thin film wiring pattern is formed with an input side outer lead, provided the input side outer lead and the output side outer leads in the organic insulating tape place in a direction perpendicular to the sprocket hole arrangement direction, the distance from the end of the semiconductor integrated circuit device to said output side outer leads, said semiconductor Longer construction than the distance from the end of the AND circuit element to the input-side outer leads
Liquid crystal, and the wiring for connecting the output side outer lead from the end of the semiconductor integrated circuit device, characterized in that it places the tape carrier package the LCD driver along the reflective sheet covering the light source Display device.