JP4030627B2 - Integrated liquid crystal display panel with image sensor function - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to an integrated liquid crystal display panel having an image sensor function, and in particular, an active matrix panel composed of a pixel portion composed of a plurality of pixel electrodes, a portable terminal having a pixel portion, and an electronic device such as a personal computer. And a manufacturing method thereof.
[0002]
[Prior art]
There is known a liquid crystal panel in which a voltage is applied to a liquid crystal layer from a pixel electrode to align the liquid crystal and form an image on a display unit.
The configuration of a conventional liquid crystal panel will be briefly described below.
The element substrate in which the display portion and the peripheral circuit formed of a thin film transistor are formed over an insulating substrate and the counter substrate are bonded to each other by a spacer while a substrate interval is maintained by a spacer. The liquid crystal is provided between the element substrate and the counter substrate. The liquid crystal is sandwiched between a pair of substrates and surrounded by a seal portion. Further, a polarizing plate is provided on the substrate, and a backlight is provided on the back surface of the substrate.
[0003]
In the above conventional configuration, the element substrate refers to a substrate provided with an active matrix circuit and a peripheral circuit. Further, the counter substrate is a substrate provided so as to be opposed to the element substrate, on which a counter electrode, a color filter, and the like are formed.
[0004]
On the other hand, as an image sensor, it is currently used in a wide range of fields as an optical sensor for converting images of copying machines, digital still cameras, video cameras, facsimiles, etc. into electrical signals, and a device configuration incorporating an optical sensor module It is said.
[0005]
[Problems to be solved by the invention]
The present inventor operates a conventional method and apparatus for manufacturing an active matrix display device at a low cost, that is, a device having both a display function and an imaging function, that is, a device having a liquid crystal panel and an image sensor on the same substrate. Thought to get.
[0006]
As described above, when the liquid crystal panel and the image sensor are manufactured on the same substrate, various problems due to the manufacturing on the same substrate have occurred.
[0007]
In particular, since a glass substrate is used, various incident light affects the sensor unit and causes noise. For example, as shown in FIG. 6, scattered light from the counter substrate and incident light from the TFT substrate side can be cited as causes of noise. In addition, since a backlight is used for liquid crystal display, light from the backlight affects the sensor unit. In particular, as shown in FIG. 6, light 606 that has been repeatedly reflected in a complicated manner in the glass substrate has been a problem.
[0008]
[Problems to be solved by the invention]
It is an object of the present invention to provide an inexpensive liquid crystal display panel having a sensor unit capable of reading a good image with respect to a liquid crystal display panel having a display unit and an image sensor on the same substrate.
[0009]
In particular, it is an object of the present invention to prevent noise caused by light incident on the sensor unit repeatedly in a complicated manner.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the sensor unit of the present invention is configured to be surrounded by a light shielding material or a light absorption film.
[0011]
The configuration of the present invention disclosed in this specification includes a display portion and a sensor portion on a transparent substrate, and the display portion includes a matrix pixel electrode and a first electrode connected to the pixel electrode. An active element, and the sensor unit includes a photoelectric conversion element and a second active element connected to the photoelectric conversion element, and a first light is provided on a side of the sensor unit. An absorber is provided, and a portion of the second substrate facing the transparent substrate that faces the sensor portion has a window through which light enters, and the second substrate is the transparent of the second substrate. Surrounding the window is a first light-shielding object provided on the surface opposite to the substrate and a second light-absorbing material provided on the surface of the second substrate facing the transparent substrate. Having a portion corresponding to the lower portion of the sensor portion on the surface opposite to the surface of the sensor portion of the transparent substrate. An integral liquid crystal display panel having an image sensor function, wherein the second light-shielding material is provided.
[0012]
In another aspect of the invention, the width of the first light absorber is 0.01 μm or more, the width of the first light absorber is 10 μm to 5 cm, and 1 is an integrated liquid crystal display panel having an image sensor function , wherein the width of the light absorber is 100 μm to 3 cm .
[0013]
Note that in the above structure, the light absorber is an integrated liquid crystal display panel having an image sensor function, wherein the light absorber is made of an organic resin material in which a pigment or a carbon-based material is dispersed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An integrated liquid crystal display panel having an image sensor function according to this embodiment will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional configuration diagram of the present embodiment, and FIG. 2 is a top view of the present embodiment.
[0016]
As shown in FIG. 1, the liquid crystal display unit has a structure in which a liquid crystal 106 is provided between an element substrate 100 and a counter substrate 101. On the element substrate 100, a display portion 104 made of a thin film transistor and a sensor portion 105 made of a photoelectric conversion element are formed. A light absorption film 107 is provided on the side of the sensor unit. The element substrate 100 and the counter substrate 101 are bonded to each other with a sealing material 103 containing a material that absorbs or blocks light. Further, an external light shield 110 is provided at a position corresponding to the lower part of the sensor portion on the back surface of the element substrate 100, and the external light shield 111 is similarly provided on the counter substrate 101. In order to further improve the light shielding property, the light shielding material 111 and the light absorption film 108 are provided on both surfaces of the counter substrate.
[0017]
As shown in FIG. 2, the liquid crystal display unit 104, the peripheral drive circuit 112, and the sensor unit 105 are provided on the same substrate. The external light shield 111 of the counter substrate has a window for reading an optical signal.
[0018]
Among these light shields, the light absorption film 107 provided on the side portion of the sensor portion is formed simultaneously with the element in the element substrate manufacturing process. The light absorption film 107 is desirably formed in contact with the element substrate as much as possible. The thickness of the light absorption film 107 is 0.01 to 1 μm, preferably 0.1 to 0.5 μm. The light absorption film 107 is provided mainly for the purpose of absorbing light that is repeatedly reflected in a complicated manner in the glass substrate. Therefore, as the width of the groove is wider than the thickness, the light reflected in the substrate can be absorbed. The groove width of the light absorption film 107 is 0.01 μm or more, preferably 10 μm to 5 cm, typically 100 μm to 3 cm.
[0019]
Instead of the light absorption film 107, a groove may be formed in a grit shape (fine mesh shape), and a light absorbing material may be buried in the groove. Then, after the element substrate is completed, the light shields 110 and 111 are attached to the substrate. The material of the light shielding material and the light shielding film is not particularly limited as long as it blocks light.
[0020]
With the above structure, light that is repeatedly reflected in a complicated manner in the glass substrate is absorbed by the light absorption film 107 provided in contact with the substrate while being repeatedly reflected in the glass substrate. Further, the light from the backlight 109 can be blocked by the light blocking members 110 and 111 and the light absorption film 107.
[0021]
【Example】
Examples of the present invention will be described below, but the present invention is of course not limited to these examples.
[Embodiment 1] In this embodiment, an example of a manufacturing process of an integrated liquid crystal display panel having an image sensor function in which a sensor portion is surrounded by a light absorbing film or a light shielding material and light incident as noise is blocked is shown in FIGS. 4 will be described in detail.
[0022]
First, the base film 301 is formed on the entire surface of the transparent substrate. A glass substrate or a quartz substrate can be used as the transparent substrate 300. A silicon oxide film having a thickness of 200 nm was formed as a base film by plasma CVD.
[0023]
Next, an amorphous silicon film was formed to a thickness of 30 to 100 nm, preferably 30 nm, by plasma CVD, and irradiated with excimer laser light to form a polycrystalline silicon film. Note that as a method for crystallizing the amorphous silicon film, a thermal crystallization method called SPC, an RTA method of irradiating infrared rays, a method using thermal crystallization and laser annealing, or the like can be used.
[0024]
Next, the polycrystalline silicon film is patterned to form an island-shaped semiconductor layer 302 constituting the source region, drain region, and channel formation region of the TFT. Next, a gate insulating film 303 covering these semiconductor layers is formed. The gate insulating film is formed to a thickness of 120 nm by plasma CVD using silane (SiH ₄ ) and N ₂ O as source gases. [Fig. 3 (A)]
[0025]
Next, an aluminum film is formed to a thickness of 300 to 500 nm, in this embodiment, 300 nm by sputtering. In order to suppress generation of hillocks and whiskers, the aluminum film contains scandium (Sc), titanium (Ti), and yttrium (Y) in an amount of 0.04 to 1.0% by weight.
[0026]
Next, an anodic oxide film having a dense film quality (not shown) is formed on the surface of the aluminum film. To form the anodic oxide film, an aluminum film is used as an anode and platinum is used as a cathode in an ethylene glycol solution containing 3% tartaric acid, and a current is passed between the electrodes. The thickness of the anodized film is controlled by the applied voltage. In this embodiment, the thickness of the anodic oxide film is 10 to 30 nm.
[0027]
Next, a resist mask is formed, and the aluminum film is patterned to form an electrode pattern.
[0028]
Then, anodic oxidation is again performed to form porous anodic oxide films 306 on the side surfaces of the electrode patterns. In this case, the anodic oxidation step may be performed by passing an electric current between the electrodes in an aqueous oxalic acid solution having a concentration of 3% with the electrode pattern as an anode and platinum as a cathode. The thickness of the anodized film can be controlled by the voltage application time. The anodized film is used for forming a low concentration impurity region in the semiconductor layer in a self-aligning manner.
[0029]
Then, after removing the resist mask with a dedicated stripping solution, an anodic oxidation process is performed again to form an anodic oxide film 305 having a dense film quality around the electrode pattern. The electrode pattern that has not been anodized in the above anodization step functions as a substantial gate electrode. The anodic oxide film having a dense film quality formed around the gate electrode functions to electrically and physically protect the gate electrode. Furthermore, an offset structure can be formed in a self-aligned manner by these anodic oxide films.
[0030]
Next, in order to impart N-type conductivity to the semiconductor, P ions are doped. In this embodiment, an ion doping method is used. The conditions are a dose of 1 × 10 ¹⁵ / cm ² and an acceleration voltage of 80 kv. As a result, the gate electrode 304 and the anodic oxide film 305 function as a mask, and N-type impurity regions are formed in the semiconductor layers in a self-aligned manner (FIG. 3B).
[0031]
Next, after removing the porous anodic oxide film 306, P ions are doped again by an ion doping method. The doping conditions are a dose of 5 × 10 ¹³ / cm ² and an acceleration voltage of 70 kv. As a result, the regions where P ions are implanted in the two doping steps become N-type high concentration impurity regions 307 and 311, and the regions where P ions are implanted only in the second doping step are N-type low concentration impurities. Regions 308 and 310 are formed. In addition, a region where P ions are not implanted in the two doping steps becomes a channel formation region 309. (Figure 3 (C))
[0032]
In addition, an offset structure is formed in a self-aligned manner in the lower region of the dense anodic oxide film in the region between the source region and the drain region.
[0033]
Thereafter, although not shown, when a P-channel TFT constituting a CMOS structure is manufactured, the other semiconductor layer is covered with a resist mask in order to invert the N-type impurity region of the semiconductor layer to the P-type. In this state, B ions imparting P-type conductivity are implanted by ion doping. The conditions are a dose of 2 × 10 ¹⁵ / cm ² and an acceleration voltage of 65 kV. As a result, the conductivity type of the N-type impurity region is inverted to become a P-type impurity region. Then, laser annealing is performed to activate the doped P ions and B ions, whereby a P-channel TFT can be manufactured.
[0034]
Then, a first interlayer insulating film 312 is formed, and a contact hole reaching the N-type high concentration impurity region is formed. At this time, a large groove for forming a light shielding film is formed at the same time. Silicon is a stopper at the bottom of the contact hole, but since there is no stopper in the light absorption film formation region 320, the base film and a part of the substrate surface are also removed depending on the etching conditions. Further, it is preferable to remove the substrate surface because reflected light in the substrate is scattered.
[0035]
Alternatively, the contact hole forming step and the groove forming step for forming the light shielding film may be performed separately.
[0036]
Thereafter, a metal film is formed and patterned to form a wiring 313. [FIG. 3D] When obtaining a CMOS structure, the N-type high concentration impurity region and the P-type impurity region are connected by wiring in this step.
[0037]
In this embodiment, the first interlayer insulating film is formed of a silicon nitride film having a thickness of 500 nm. In addition to the silicon nitride film, a silicon oxide film or a silicon nitride film can be used as the first interlayer insulating film. Further, a multilayer film of these insulating films may be used.
[0038]
In this embodiment, a laminated film made of a titanium film, an aluminum film, and a titanium film is formed as a metal film to be a wiring starting film by sputtering. These film thicknesses are 100 nm, 300 nm, and 100 nm, respectively.
[0039]
Through the above process, the light receiving portion TFT is completed at the same time.
[0040]
Next, a second interlayer insulating film 314 that covers the TFT is formed. The second interlayer insulating film is preferably a resin film that cancels out unevenness in the lower layer and obtains a flat surface. As such a resin film, polyimide, polyamide, polyimide amide, or acrylic can be used. The surface layer of the second interlayer insulating film may be a resin film in order to obtain a flat surface, and the lower layer may be a single layer or a multilayer of an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. In this embodiment, a polyimide film is formed to a thickness of 1.5 μm as the second interlayer insulating film.
[0041]
Next, a contact hole reaching the wiring of the light receiving portion TFT is formed in the second interlayer insulating film, and at the same time, the second interlayer insulating film is removed in a large groove shape for forming a light shielding film. Thereafter, a conductive film is formed. In this embodiment, a titanium film having a thickness of 200 nm is formed as the conductive film by a sputtering method.
[0042]
Next, the conductive film is patterned to form a lower electrode 315 connected to the light receiving portion TFT. Titanium or chromium can be used as the conductive film. [Fig. 3 (E)]
[0043]
Next, an amorphous silicon film 316 containing hydrogen (hereinafter referred to as an a-Si: H film) that functions as a photoelectric conversion layer is formed over the entire surface of the substrate.
[0044]
Next, a transparent conductive film 317 is formed on the entire surface of the substrate and patterned to form a transparent electrode of the photoelectric conversion element. ITO or SnO ₂ can be used for the transparent conductive film. In this embodiment, an ITO film having a thickness of 120 nm is formed as the transparent conductive film. At the same time, the amorphous silicon film and the transparent conductive film are removed to form a light shielding film. [FIG. 4 (A)]
[0045]
Next, an acrylic resin in which a black pigment is dispersed is applied to the groove by a spin coating method and cured to form a light absorption film 318 with a thickness of 0.3 to 5 μm. In this embodiment, the thickness of the light absorption film 318 is set to 0.5 μm. The groove width of the light absorption film 107 is 0.01 μm or more, preferably 10 μm to 5 cm, and 1 cm in this embodiment.
[0046]
In addition, the light absorption film 318 that absorbs light that is reflected in a complicated manner in the substrate is likely to absorb light when formed as close as possible to the substrate.
[0047]
The light absorption film 318 is a coating film that can be formed from a solution. As such a coating film, an organic resin film such as acrylic, polyimide, polyamide, epoxy, and polyimideamide is used. Further, as a film that can be formed from a solution, a silicon oxide-based coating film such as PSG or SiO ₂ can be used.
[0048]
The groove portion may have a structure in which a layer made of a light absorber and an insulating layer are stacked.
[0049]
Through the above steps, an element substrate as shown in FIG. 4C is completed.
[0050]
[Example 2]
In the first embodiment, an example in which the TFT constituting the light receiving element is made of a top gate type TFT is shown. In this embodiment, an example in which these TFTs are formed of bottom type TFTs is shown. FIG. 5 shows a cross-sectional configuration diagram of the element substrate of this example.
[0051]
The bottom gate TFT of this embodiment includes a gate electrode 505 formed on the base film 501, a semiconductor layer 502 formed on the gate insulating film 503, and a channel stopper 523 formed on the channel region of the semiconductor layer. And wirings 514 and 515 connected to the semiconductor layer. Reference numeral 518 denotes a lower electrode, 519 denotes a photoelectric conversion layer, and 520 denotes an upper electrode. Reference numeral 521 denotes a light absorption film.
[0052]
The light absorption film 521 is formed to a thickness of 0.5 to 4 μm. In this embodiment, the thickness of the light absorption film 318 is 0.8 μm. The groove width of the light absorbing film 107 is 0.01 μm or more, preferably 10 μm to 5 cm, and 3 cm in this embodiment.
[0053]
A manufacturing process of the bottom gate type TFT of this embodiment may be a known manufacturing method, and all TFTs are completed by the same process as in Embodiment 1.
[0054]
Example 3
FIG. 7 shows an example of an electronic device when the apparatus formed in the first embodiment or the second embodiment is modularized.
[0055]
FIG. 7A shows a notebook personal computer, and the panel of this embodiment is applied to the display portion 2001 and the sensor portion 2003. FIG. 7B illustrates a videophone with a sensor, which includes a small display portion 2101 and a sensor portion 2103. FIG. 7C illustrates an example in which the display portion 2201 and the two area sensors 2203 are applied to a notebook personal computer. FIG. 7D illustrates a portable information terminal with a sensor, which similarly includes a display portion 2301 and a sensor portion 2303.
[0056]
【The invention's effect】
In the present invention, in addition to the location of the sensor light receiving portion, an external light shielding material and a light absorption film are provided, thereby blocking scattered light in the substrate or light from the backlight and suppressing noise in the sensor portion.
[0057]
According to the present invention, an inexpensive liquid crystal display panel having a sensor unit capable of reading a good image can be obtained with respect to a liquid crystal display panel having a display unit and an image sensor on the same substrate.
[Brief description of the drawings]
FIG. 1 is a sectional structural view of the present invention (top TFT).
2 is a top view of the present invention. FIG. 3 is a fabrication process diagram of the present invention. FIG. 4 is a fabrication process diagram of the present invention. FIG. 5 is a sectional structure diagram of the present invention (bottom type TFT).
FIG. 6 is a diagram showing light repeatedly reflected in a complicated manner in a glass substrate. FIG. 7 is an application example of the present invention.
DESCRIPTION OF SYMBOLS 100 Element substrate 101 Opposite substrate 103 Black sealing material 104 Liquid crystal display part 105 Sensor part 106 Liquid crystal material 107 Light absorption film 108 Light absorption film 109 Backlight 110 External light shield 111 External light shield 112 Peripheral drive circuit part 300 Element substrate 301 Base film 302 Island-like semiconductor layer 303 Gate insulating film 304 Gate electrode 305 Dense anodic oxide film 306 Porous anodic oxide films 307 and 311 High-concentration impurity regions 308 and 310 Low-concentration impurity regions 309 Channel formation region 312 First interlayer insulating film 313 Wiring 314 Second interlayer insulating film 315 Lower electrode 316 Amorphous silicon film 317 Transparent conductive film 318 Light absorption film 600 Element substrate 601 Counter substrate 604 Liquid crystal display portion 605 Sensor portion 606 Intricate reflection repeatedly in the glass substrate Light 609 Backlight

Claims (5)

A display unit and a sensor unit on a transparent substrate;
The display unit includes a matrix-shaped pixel electrode and a first active element connected to the pixel electrode,
The sensor unit includes a photoelectric conversion element and a second active element connected to the photoelectric conversion element,
A side portion of the sensor unit is provided with a first light absorber,
The portion of the second substrate facing the transparent substrate that faces the sensor portion has a window through which light enters.
The second substrate is
A first light-shielding object provided on a surface of the second substrate opposite to the transparent substrate;
A second light-absorbing material provided on the surface on the side facing the transparent substrate of the second substrate, the possess surrounding the window,
An integral type having an image sensor function, wherein a second light-shielding object is provided at a portion corresponding to a lower portion of the sensor portion on the surface opposite to the surface of the sensor portion of the transparent substrate. LCD display panel. In claim 1,
An integrated liquid crystal display panel having an image sensor function, wherein the width of the first light absorber is 0.01 μm or more. In claim 1,
An integrated liquid crystal display panel having an image sensor function, wherein the width of the first light absorber is 10 μm to 5 cm. In claim 1,
An integrated liquid crystal display panel having an image sensor function, wherein the width of the first light absorber is 100 μm to 3 cm. In any one of Claims 1 thru | or 4,
The integrated liquid crystal display panel having an image sensor function, wherein the first light absorber is made of an organic resin material in which a pigment or a carbon-based material is dispersed.

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