JPH09160014A - Active matrix type liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the malfunction of thin-film transistors(TFTs) by light leakage currents and the degradation in the contrast of liquid crystal display elements by surely suppressing the incidence of the light of a UV region to far IR region on the (i) type semiconductor films of these TFTs. SOLUTION: First light shielding films 21 consisting of a material which absorbs the light of visible band wavelengths and has the transmittance of <=0.5% of the light in the visible region are formed it regions between the respective pixels on a substrate 9 of an opposite panel 2. Next, the second light shielding films 22 consisting of a material which absorbs the light of the wavelength bands of the UV region and the near IR region to far IR region are formed on the respective TFTs 7 so as the cover the channel regions of the (i) type semiconductor films 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display element that controls light transmission by a liquid crystal to display an image.

[0002]

2. Description of the Related Art In an active matrix type liquid crystal display device, a thin film transistor panel and a counter panel are joined together through a frame-shaped sealing material, and liquid crystal is sealed in a gap between both panels inside the sealing material. Become.

A thin film transistor panel includes a plurality of transparent pixel electrodes vertically and horizontally arranged on a transparent substrate made of glass, a plurality of thin film transistors connected to the pixel electrodes, and a plurality of gate signals supplied to the thin film transistors. Of gate lines and a plurality of data lines for supplying a data signal to the thin film transistor are formed in a grid pattern. In the counter panel, a black light-shielding black mask made of Cr is formed on a transparent substrate made of glass or the like, and is opposed to all pixel electrodes in the thin film transistor panel via an insulating film on the black mask. A transparent counter electrode is formed.

Openings are formed in the black mask so as to face the respective pixel electrodes of the thin film transistor panel, and in a liquid crystal display element for displaying a color image, color filters are formed corresponding to the respective openings of the black mask. . The outer surface of the counter panel is usually used as an image display surface.

[0005]

The i-type semiconductor film made of a-Si (amorphous silicon) in a thin film transistor has a property of absorbing light in a wide wavelength range from ultraviolet rays to far infrared rays. Each thin film transistor of the thin film transistor panel faces a black mask made of Cr provided on an opposite panel and is shielded from light by this black mask, but Cr transmits light in a wavelength range near 910 nm which is a near infrared region. Therefore, light in this wavelength range is emitted by the thin film transistor i.
The incident light is incident on the semiconductor film, and the light leakage current caused by the incident makes the operation of the thin film transistor unstable, resulting in display defects such as reduction in contrast.

The present invention has been made by paying attention to such a point, and an object thereof is to reliably suppress the incidence of light in the ultraviolet region to the far infrared region on the i-type semiconductor film of the thin film transistor and to perform the light irradiation. An object of the present invention is to provide an active matrix type liquid crystal display element capable of preventing malfunction of a thin film transistor due to a leak current.

[0007]

In order to achieve such an object, the present invention is a thin film transistor in which a plurality of pixel electrodes and a plurality of thin film transistors corresponding to these pixel electrodes are formed on a transparent substrate. A panel and a counter panel formed by forming a counter electrode on a transparent substrate are joined with a frame-shaped sealing material, and a liquid crystal is sealed in a gap surrounded by the sealing material and both panels. In the active matrix liquid crystal display element, a first light-shielding film made of a material that absorbs light in a visible band wavelength so as to cover at least the channel region of the semiconductor film of the thin film transistor,
A second light-shielding film made of a material that absorbs light in the wavelength range of the ultraviolet region and the near-infrared to far-infrared region is formed.

In the invention according to claim 2,
The first light-shielding film was formed in a region between each pixel on the substrate of the counter panel, and the second light-shielding film was formed on each thin-film transistor so as to cover the channel region of the semiconductor film. In the invention according to claim 3, the first light-shielding film is formed on the substrate in the counter panel and in a portion of a region facing each of the thin film transistors, and To
The second light-shielding film is formed so as to cover the channel region of the semiconductor film. In the invention according to claim 4, the first light-shielding film is formed in a region between pixels on the substrate in the counter panel. The light-shielding film and the second light-shielding film are stacked to be formed, and in the invention according to claim 5, the channel region of the i-type semiconductor film is covered on each thin film transistor. The second light-shielding film is formed, and the first light-shielding film is formed on the second light-shielding film and in a portion extending over a region between pixels.
The invention according to claim 6 is characterized in that the second light-shielding film and the first light-shielding film are laminated on each of the thin film transistors so as to cover a channel region of a semiconductor film, In the invention according to claim 7, the first light-shielding film is made of a carbon black-based material made of a mixture of carbon and resin, and has a light transmittance in the visible region.
It is 0.5% or less, and the second light-shielding film is characterized by being made of a pigment-based material in which a dark pigment is dispersed in a resin.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment. 1 and 2, the thin film transistor panel 1 and the counter panel 2 are shown.
The alignment film above is omitted.

FIG. 3 is a schematic cross-sectional view of an active matrix type liquid crystal display element. In this liquid crystal display element, a thin film transistor panel 1 and a counter panel 2 are joined together via a frame-shaped sealing material 3, A liquid crystal 4 is enclosed in a space surrounded by the panels 1 and 2 and the frame-shaped sealing material 3.

In the thin film transistor panel 1, a large number of pixel electrodes 6 and thin film transistors 7 corresponding to the pixel electrodes 6 are arranged in a matrix on a transparent substrate 5 such as glass, and polyimide or the like is further formed on the substrate 5. The alignment film 8 is formed. The opposite panel 2 is
A color filter 10 is formed on a transparent substrate 9 such as glass (the lower surface in the figure), and a single plate-shaped counter electrode 11 facing all of the pixel electrodes 6 is formed on the color filter 10. An alignment film 12 made of polyimide or the like is formed on the counter electrode 11.

As shown in FIGS. 1 and 2, the thin film transistor 7 is made of Al or Al formed on the substrate 5.
A gate electrode G made of a system alloy, a transparent gate insulating film 15 made of Si N (silicon nitride) formed on the gate electrode G, and a gate electrode G on the gate insulating film 15 facing the gate electrode G. Formed by a-Si (amorphous silicon) i-type semiconductor film 16, and n formed by a-Si doped on the i-type semiconductor film 16 except for its channel region The type semiconductor film 17 and the drain electrode D and the source electrode S formed on the n-type semiconductor film 17. Reference numeral 18 is a blocking insulating film made of Si 2 N formed on the channel region of the i-type semiconductor film 16. The blocking insulating film 18 is an i-type semiconductor during etching for separating the n-type semiconductor film 17 in the channel region. Membrane 1
It is provided to prevent 6 from being damaged.

The gate electrode G of the thin film transistor 7
Are integrally formed with the gate line GL wired on the substrate 5, and the gate line GL is covered with the gate insulating film 15, and the pixel electrode 6 and the data line DL are formed on the gate insulating film 15. Has been formed.

The pixel electrode 6 is a transparent conductive film such as ITO, and one edge thereof is connected to the source electrode S of the thin film transistor 7. The data line DL is formed integrally with the drain electrode D of the thin film transistor 7, and the data line DL and the drain electrode D and the source electrode S are formed.
Is formed of a metal such as Al or an Al-based alloy.

On the other hand, in the counter panel 2, as shown in FIG. 1, a first light-shielding film 21 is formed on the substrate 9 (lower surface in the figure), and a color is formed so as to cover the first light-shielding film 21. A filter 10 is formed, and this color filter 1
A transparent counter electrode 11 that faces all the pixel electrodes 6 of the thin film transistor panel 1 is formed on top of 0.

In FIG. 2, the pattern of the first light-shielding film 21 is shown by hatching, and the first light-shielding film 21 forms a large number of openings 21a corresponding to the respective pixel electrodes 6 of the thin film transistor panel 1. It is formed as a grid pattern, and the areas of the pixels are optically divided by the openings 21a,
The color filters 10 colored red, green and blue are formed corresponding to the respective openings 21a of the light shielding film 21. The size of each opening 21a of the light-shielding film 21 is such that even if a slight horizontal displacement occurs between the thin film transistor panel 1 and the counter panel 2, the displacement is absorbed and the pixel region is appropriately divided. In order to be able to do so, it is formed to be slightly smaller than the size of the pixel electrode 6.

The first light-shielding film 21 absorbs light in the visible wavelength range (300 to 700 nm), and particularly has a light transmittance of 0.5% or less in the visible region and reflects light with a wavelength of 550 nm. A material having a ratio of 1.5% or less, for example, a carbon black-based material made of a mixture of carbon and resin is used, and the film thickness is formed in the range of 0.5 to 2.0 μm.

On the other hand, on each of the thin film transistors 7, a second region that covers at least the channel region of the i-type semiconductor film 16 is formed.
The light shielding film 22 is formed. This second light shielding film 22
Is a material that absorbs light in the ultraviolet region (200 to 400 nm) and near infrared to far infrared region (700 to 1000 nm), for example, a pigment-based material in which a dark pigment is dispersed in a resin. The film thickness is 0.5 to 1.0 μm. And, in particular, in order to efficiently absorb the light of the wavelength of the ultraviolet region (200 to 400 nm), the particle size of the dark pigment dispersed in the resin is set to 0.2 μm or less, and the surface resistance value per unit area of the film is set. 10 ¹⁴ Ω / □ (specific resistance 10 ⁹ Ω · cm)
There is.

The second light-shielding film 22 is the i-type semiconductor film 1
In order to prevent incidence of light to the channel region of No. 6 due to wraparound, a film is formed from the channel region to a region above the source electrode S and the drain electrode D, and further, a specific alignment of liquid crystal molecules at the edge portion. In order to prevent the occurrence of the above, the side surface of the thin film transistor 7 is formed in a tapered shape of about 15 to 65 ° along the protruding tapered shape.

In the liquid crystal display element having such a structure, the surface of the opposite panel 2 on the outer surface side of the substrate 9 is used as an image display surface. Therefore, external light is incident from the opposite panel 2 toward the thin film transistor panel 1. .

When the thin film transistor 7 is projected from the outside light incident side, the first light shielding film 21 and the second light shielding film 22 are sequentially overlapped with the thin film transistor 7. Become. The first light shielding film 21 is
It is made of a material that absorbs light in the visible wavelength range (300 to 700 nm) and that has a light transmittance of 0.5% or less, especially in the visible range.
The second light-shielding film 22 is formed in the ultraviolet region (200 to 400 n).
m) and a material that absorbs light in the near infrared to far infrared region (700 to 1000 nm) wavelength band, the visible band wavelength (of the light incident from the counter panel 2 toward the thin film transistor 7) The light of 300 to 700 nm) is absorbed by the first light shielding film 21, and the ultraviolet region (200 to 400 nm) transmitted through the first light shielding film 21 and the near infrared to far infrared region (700 to 1000 nm). The light in the wavelength band is absorbed by the second light-shielding film 22, and as a result, the light in the ultraviolet region to the far-infrared region is suppressed from entering the i-type semiconductor film 16 of the thin film transistor 7, and therefore the light leakage current is caused. The malfunction of the thin film transistor 7 is prevented, and the occurrence of display defects such as reduction in contrast is eliminated.

The first light-shielding film 2 on the image display side
No. 1 is a material that absorbs light in the visible region and has a low reflectance of 1.5% or less, so the reflection on the image display surface can be significantly reduced compared to the conventional Cr film, and the image display quality is improved. To do.

In the first embodiment, the first light-shielding film 21 is formed so as to cover the entire region between the pixels, but as shown in FIGS. 4 and 5 as the second embodiment, the thin film transistor is formed. 7 may be provided only in a partial position facing 7, and even in this case, of the light incident from the facing panel 2 toward the thin film transistor 7,
Light in the visible band wavelength (300 to 700 nm) is absorbed by the first light shielding film 21 formed on the counter panel 2, and
UV region (200-400 nm) transmitted through the light-shielding film 21 of
And light in the near infrared to far infrared region (700 to 1000 nm) wavelength band is formed on the thin film transistor 7.
Is absorbed by the light-shielding film 22 of the thin film transistor 7, and eventually the i-type semiconductor film 16 of the thin film transistor 7 is prevented from being incident with light in the ultraviolet region to the far infrared region, and malfunction of the thin film transistor 7 due to light leakage current is prevented. The occurrence of display defects such as deterioration of the display is eliminated.

FIG. 6 shows a third embodiment. In this third embodiment, the first light-shielding film is formed in the area between the pixels on the substrate 9 of the counter panel 2. Two
The first light shielding film 22 and the second light shielding film 22 are stacked.

The first light-shielding film 21 has a visible band wavelength (300
From a mixture of carbon and resin that absorbs light up to 700 nm) and that has a light transmittance of 0.5% or less in the visible region and a light reflectance of 1.5% or less for the wavelength of 550 nm. Made of carbon black material,
The film thickness is 0.5 to 2.0 μm. The second light-shielding film 22 is a material that absorbs light in the ultraviolet region (200 to 400 nm) and near infrared to far infrared region (700 to 1000 nm) wavelength band, for example, a dark pigment dispersed in a resin. It is made of pigment-based material and has a film thickness of 0.5 to 1.0 μm. And especially in the ultraviolet region (200-400 n
In order to efficiently absorb the light of wavelength m), the particle size of the pigment is 0.2 μm or less.

A plurality of openings 23 having substantially the same size as the pixel electrodes 6 in the thin film transistor panel 1 are formed in the first light-shielding film 21 and the second light-shielding film 22 in the laminated state so as to face each pixel electrode 6 in a matrix. It is formed into a shape.
The color filters 10 colored red, green, and blue are formed corresponding to the openings 23, and the counter electrode 11 is formed on the color filters 10.

An example of the step of forming the first and second light-shielding films 21 and 22 will be described. First, the substrate 9 is washed, and a carbon black-based resist material for the first light-shielding film is placed on the substrate 9. Coating is performed using a spinner or the like, and this coating film is prebaked.

Next, on the coating film of the resist material,
The pigment-based resist material for the second light-shielding film is applied using a spinner or the like, and this applied film is prebaked. Next, the coating films of the two layers of resist material are collectively exposed and developed to form first and second light-shielding films 21 having a predetermined pattern,
Get 22.

After that, the substrate 9 is washed by high-pressure water washing, and post-baking is performed after this washing to fire the first and second light-shielding films 21 and 22. In the liquid crystal display device having such a configuration, the surface of the opposite panel 2 on the outer surface side of the substrate 9 is used as an image display surface, and therefore external light is incident from the opposite panel 2 toward the thin film transistor panel 1.

When the thin film transistor 7 is projected from the outside light incident side, the first light shielding film 21 and the second light shielding film 22 are arranged so as to overlap the thin film transistor 7. . The first light-shielding film 21 is made of a material that absorbs light in the visible band wavelength (300 to 700 nm) and has a light transmittance of 0.5% or less particularly in the visible region. Is in the ultraviolet range (200-400 nm)
Since it is made of a material that absorbs light in the wavelength range of near infrared to far infrared (700 to 1000 nm), the visible band wavelength (300 to 300 nm) of the light incident from the counter panel 2 toward the thin film transistor 7 is absorbed. The light of 700 nm) is absorbed by the first light-shielding film 21, and the wavelength band of the ultraviolet ray region (200 to 400 nm) and the near-infrared to far-infrared ray region (700 to 1000 nm) transmitted through the first light-shielding film 21. Light of the thin film transistor 7 is absorbed by the second light-shielding film 22.
Light from the ultraviolet region to the far infrared region is suppressed from entering the type semiconductor film 16, so that the thin film transistor 7 is prevented from malfunctioning due to a light leak current, and a display defect such as a decrease in contrast is eliminated.

The first light-shielding film 2 on the image display side
No. 1 is a material that absorbs light in the visible region and has a low reflectance of 1.5% or less, so the reflection on the image display surface can be significantly reduced compared to the conventional Cr film, and the image display quality is improved. To do.

FIG. 7 shows a fourth embodiment. In the fourth embodiment, a second light shielding film 22 is formed on the thin film transistor 7, and the second light shielding film 22 is further formed. A first light-shielding film 21 is formed by stacking on top.

The second light shielding film 22 is formed by the thin film transistor 7
Is formed on at least a portion of the i-type semiconductor film 16 that covers the channel region. The first light-shielding film 21 covers the second light-shielding film 22 and is spread in a region serving as a region between pixels to form a lattice pattern.

The material of the second light-shielding film 22 in this embodiment is composed of ultraviolet rays (200 to 400 nm) and near infrared rays.
A material that absorbs light in the wavelength band in the far infrared region (700 to 1000 nm), for example, a pigment-based material in which a dark pigment is dispersed in a resin, has a film thickness of 0.5 to 1.0 μm.
In addition, the particle size of the pigment is 0.2 so that light with a wavelength in the ultraviolet range (200 to 400 nm) can be efficiently absorbed.
μm or less.

The material of the first light-shielding film 21 absorbs light in the visible band wavelength (300 to 700 nm), and particularly has a light transmittance of 0.5% or less in the visible region and has a wavelength of 550 nm. A material having a reflectance of 1.5% or less, for example, a carbon black-based material made of a mixture of carbon and resin,
The film thickness is 0.5 to 2.0 μm.

On the substrate 9 of the counter panel 2, color filters 10 colored red, green and blue are formed corresponding to the respective pixel electrodes 6, and all the thin film transistor panels 1 are formed on the color filters 10. A transparent counter electrode 11 that faces the pixel electrode 6 of is formed.

In the liquid crystal display device having such a structure, the surface of the opposite panel 2 on the outer surface side of the substrate 9 is used as an image display surface. Therefore, external light is incident from the opposite panel 2 toward the thin film transistor panel 1. .

Here, the second thin film is formed on the thin film transistor 7.
The light-shielding film 22 and the first light-shielding film 21 are laminated and arranged, and the second light-shielding film 22 is formed in the ultraviolet region (200 to 400).
nm) and near infrared to far infrared region (700 to 1000 nm)
The first light-shielding film 21 absorbs light in the visible band wavelength (300 to 700 nm) and has a light transmittance of 0.5% or less particularly in the visible region. Since it is made of a material, of the light incident from the counter panel 2 toward the thin film transistor 7, light in the visible band wavelength is absorbed by the first light shielding film 21.
The light in the ultraviolet region and the near-infrared region to the far-infrared region transmitted through is absorbed by the second light-shielding film 22, so that the i-type semiconductor film 16 of the thin film transistor 7 is incident with the light in the ultraviolet region to the far-infrared region. Therefore, malfunction of the thin film transistor 7 due to light leakage current is prevented, and display defects such as reduction in contrast are eliminated.

Since the first light-shielding film 21 is formed from the region above the thin film transistor 7 to the region between the pixels, the first light-shielding film 21 prevents light from leaking between the pixels. And good display quality is obtained.

Furthermore, as in this embodiment, by providing the first light-shielding film 21 and the second light-shielding film 22 on the thin film transistor panel 1, the misalignment when the panels 1 and 2 are joined is absorbed. Therefore, it is not necessary to form the first light-shielding film 21 in a large size, and the aperture ratio can be increased. Since the first light-shielding film 21 is made of a carbon black resin material, there is no inconvenience of generating a parasitic capacitance with the wiring.

FIG. 8 shows a fifth embodiment. In the fifth embodiment, the first light-shielding film 21 and the second light-shielding film 22 are provided only in the region above each thin film transistor 7.
Are laminated.

The material of the second light-shielding film 22 is a material that absorbs light in the wavelength range of the ultraviolet region (200 to 400 nm) and the near infrared region to the far infrared region (700 to 1000 nm), for example, a dark color in resin. It is a pigment-based material in which the pigment of
The film thickness is 0.5 to 1.0 μm. The particle size of the pigment is 0.2 μm or less in order to efficiently absorb light having a wavelength in the ultraviolet region (200 to 400 nm).

The material of the first light-shielding film 21 absorbs light in the visible band wavelength (300 to 700 nm), and particularly has a light transmittance of 0.5% or less in the visible region and a wavelength of 550 nm. A material having a light reflectance of 1.5% or less, for example, a carbon black-based material made of a mixture of carbon and a resin, and having a film thickness of 0.5 to 2.0 μm.

Since the fifth embodiment has a structure in which the first light-shielding film 21 and the second light-shielding film 22 are stacked and provided only in the region above the thin film transistor 7, they are collectively patterned. It is possible to form.

That is, to explain the process in this case, first, the substrate 5 on which the thin film transistor 7 is formed is washed. Then, a pigment-based resist material for the second light-shielding film is applied onto the substrate 5 on which the thin film transistor 7 is formed by using a spinner or the like, and the applied film is pre-baked.

Next, on the coating film of the resist material,
The carbon black resist material for the first light-shielding film is applied using a spinner or the like, and this applied film is pre-baked. Next, the coating films of the two layers of resist material are collectively exposed and developed to obtain first and second light-shielding films having a predetermined pattern.

When exposing the two-layer resist material, ultraviolet rays are irradiated from the outer surface side of the substrate 5 to expose the gate wiring G.
L and the source electrode S and drain electrode D of the thin film transistor 7 are used as a mask for the exposure, and self-alignment (rear surface exposure) can be adopted for efficient exposure.

After that, the substrate 5 is washed by high-pressure water washing, and post-baking is performed after the washing to burn the first and second light-shielding films 21 and 22. In the liquid crystal display device having such a configuration, the surface of the opposite panel 2 on the outer surface side of the substrate 9 is used as an image display surface, and therefore external light is incident from the opposite panel 2 toward the thin film transistor panel 1.

Here, on the thin film transistor 7, the first
The light-shielding film 21 and the second light-shielding film 22 are stacked and arranged,
The second light shielding film 22 is formed in the ultraviolet region (200 to 400 n).
m) and a material that absorbs light in the near-infrared to far-infrared (700-1000 nm) wavelength band, the first light-shielding film 21 absorbs light in the visible band wavelength (300-700 nm). In particular, since it is formed of a material having a light transmittance of 0.5% or less in the visible region, the light incident on the thin film transistor 7 from the opposing panel 2 in the ultraviolet region (200 to 40
0 nm) and near infrared to far infrared region (700 to 1000 nm)
Light in the wavelength band of is absorbed by the second light shielding film 22, and light in the visible band wavelength (300 to 700 nm) is absorbed in the first light shielding film 21.
The absorption of light in the ultraviolet region to the far infrared region is suppressed on the i-type semiconductor film 16 of the thin film transistor 7, so that malfunction of the thin film transistor 7 due to light leakage current is prevented, and the contrast is lowered. The occurrence of the display defect of is eliminated.

FIG. 9 shows the thickness of the light-shielding film and OD (Optical).
Dencity) value is shown. The A curve shown in this graph is the characteristic of a single-layer light-shielding film formed of a pigment-based resin material in which a dark pigment is dispersed in a resin, and the B curve is a characteristic in which a dark pigment is dispersed in the resin. It is a characteristic of a light-shielding film having a two-layer structure of a layer of a pigment material and a layer of a carbon black material made of a mixture of carbon and a resin.

As shown in this graph, the light-shielding film (B curve) having a two-layer structure of a pigment material layer and a carbon black material layer is used even if the same film thickness is compared. But,
O is better than a single-layer light-shielding film (A curve) formed of a pigment material.
It can be seen that the D value is high and the low transmittance is obtained.

Further, FIG. 10 shows the relationship between the wavelength of light and the reflectance of the light shielding film. The A curve shown in this graph is the characteristic of a single-layer light-shielding film formed of a pigment-based material in which a dark pigment is dispersed in a resin, and the B curve is a pigment in which a dark pigment is dispersed in the resin. The characteristics of a light-shielding film having a two-layer structure including a layer of a system material and a layer of a carbon black-based material made of a mixture of carbon and resin, and a C curve is a characteristic of the light-shielding film made of a metal of Cr. The thickness of each light-shielding film is 1.0 μm.

As can be seen from this graph, a single-layer light-shielding film made of a pigment material (A curve) and a two-layer light-shielding film made of a pigment material layer and a carbon black material layer (B curve). In both cases, the reflectance is lower than that of the light shielding film (C curve) made of Cr metal. Further, the two-layer light-shielding film (B curve) made of the pigment-based material and the carbon black-based material can obtain a lower reflectance than the single-layer light-shielding film (A-curve) made of the pigment-based material. I understand.

Therefore, the third embodiment (FIG. 6)
As described above, the first light-shielding film 21 made of a carbon black-based material and the second light-shielding film 2 made of a pigment-based material are provided in a portion of the counter panel 2 which is a region between pixels on the substrate 9.
When the two are laminated, the reflection of external light on the image display surface can be more reliably reduced, and the display quality of the image is improved.

[0055]

As described above, according to the present invention,
Ultraviolet region for i-type semiconductor film of thin film transistor
It is possible to reliably suppress the incidence of light in the far infrared region,
Therefore, it is possible to prevent malfunction of the thin film transistor due to the light leakage current and to reliably eliminate the occurrence of display defects such as reduction in contrast. Further, the aperture ratio can be increased by collectively disposing the light shielding film on the thin film transistor side substrate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an active matrix liquid crystal display element according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a formation state of each light shielding film in the liquid crystal display element.

FIG. 3 is a sectional view schematically showing the overall structure of the liquid crystal display element.

FIG. 4 is a sectional view of a main part of an active matrix type liquid crystal display element according to a second embodiment of the present invention.

FIG. 5 is a plan view showing a formation state of each light shielding film in the liquid crystal display element.

FIG. 6 is a sectional view of a main part of an active matrix liquid crystal display element according to a third embodiment of the present invention.

FIG. 7 is a sectional view of an essential part of an active matrix type liquid crystal display element according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of a main part of an active matrix liquid crystal display element according to a fifth embodiment of the present invention.

FIG. 9 is a graph showing the relationship between the film thickness of the light shielding film and the OD value.

FIG. 10 is a graph showing the relationship between the wavelength of light and the reflectance of the light shielding film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thin film transistor panel 2 ... Opposite panel 3 ... Sealing material 4 ... Liquid crystal 5 ... Substrate 6 ... Pixel electrode 7 ... Thin film transistor 9 ... Substrate 11 ... Opposing electrode 21 ... Shading film 22 ... Shading film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01L 29/786 H01L 29/78 619B

Claims (7)

[Claims] 1. A thin film transistor panel formed by forming a plurality of pixel electrodes and a plurality of thin film transistors corresponding to these pixel electrodes on a transparent substrate, and a counter formed by forming a counter electrode on the transparent substrate. An active matrix type liquid crystal display device comprising a panel and a frame-shaped sealing material which are joined to each other, and liquid crystal is enclosed in a space surrounded by the sealing material and the both panels. At least a channel region of a semiconductor film of the thin film transistor. So as to cover the first light-shielding film made of a material that absorbs light in the visible band wavelength, an ultraviolet region and a near-infrared region.
An active matrix type liquid crystal display element, comprising: a second light-shielding film made of a material that absorbs light in a wavelength band of a far infrared region. 2. The first light-shielding film is formed in a region between pixels on the substrate of the counter panel, and the second light-shielding film is formed on the thin film transistors so as to cover the channel region of the semiconductor film. The active matrix type liquid crystal display device according to claim 1, wherein a light shielding film is formed. 3. The first light-shielding film is formed on a portion of a region of the counter panel facing the thin film transistors on the substrate, and the first light shielding film is formed on the thin film transistors.
The active matrix type liquid crystal display device according to claim 1, wherein the second light-shielding film is formed so as to cover the channel region of the semiconductor film. 4. The first light-shielding film and the second light-shielding film are laminated and formed in a region between pixels on a substrate of the counter panel. The active matrix type liquid crystal display element described. 5. A second light-shielding film is formed on each of the thin film transistors so as to cover a channel region of an i-type semiconductor film, and is formed on the second light-shielding film and in a region between pixels. The active matrix type liquid crystal display element according to claim 1, wherein the first light-shielding film is formed in a crossing portion. 6. The first light-shielding film and the second light-shielding film are stacked on each of the thin film transistors so as to cover a channel region of a semiconductor film. The active matrix type liquid crystal display element described. 7. The first light-shielding film is made of a carbon black-based material made of a mixture of carbon and a resin, and has a light transmittance of 0.5% or less in the visible region, and the second light-shielding film. Is made of a pigment-based material in which a dark pigment is dispersed in a resin.
Alternatively, the active matrix liquid crystal display element according to the item 6.