JP2001109394A - Display device integrated with image recognition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intelligent new display device integrated with an image recognition device having a pixel matrix, image sensor and peripheral circuit to drive those, that is, having both of an image recognizing function and a display function. SOLUTION: The display device has a plurality of pixels having active elements and arranged in a matrix, an active matrix substrate used as the electrode of the pixels, and a plurality of sensors disposed in a matrix on the active matrix substrate. The sensor has a photoelectron conversion element, and when an external image is to be read, the light passing through a light- transmitting material is used to read the information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates to an apparatus having both an image recognition function and an image display function. In particular, the present invention relates to a device having an active matrix display function device including a plurality of thin film transistors (TFTs) arranged in a matrix.

[0003]

2. Description of the Related Art In recent years, information devices such as personal computers have become widespread, and demands for reading various information as electronic information into personal computers and the like have increased. For this reason, scanners have attracted attention as means for reading what is printed on paper or the like. However, this scanner
It is independent as a peripheral device, and there are problems such as difficulty in operation and difficulty in location.

In such a situation, a liquid crystal panel in which a color scanner and a touch panel are integrated has been put to practical use. The configuration will be briefly described. First, there is a liquid crystal panel, on which a color scanner using a line sensor is arranged. When using a scanner, an original is placed on the screen, and the line sensor is scanned and read. This required a large area and volume.

Recently, a TFT technique using polycrystalline silicon called a polysilicon TFT has been intensively studied. As a result, a driving circuit having a shift register circuit and the like can be manufactured using a polysilicon TFT, and an active matrix type in which a pixel portion and a peripheral driving circuit for driving the pixel portion are integrated on the same substrate. Liquid crystal panels have come to practical use. For this reason, liquid crystal panels have been reduced in size and weight, and used for various information devices such as personal computers, video cameras and digital cameras, and display units of portable devices. In addition, self-luminous display devices such as organic EL are also being developed.

[0006]

Recently, a small portable information processing terminal device (mobile computer), which is more portable and cheaper than a notebook personal computer, and is inexpensive, has become popular. For example, an active matrix type liquid crystal panel is mainly used. Such an information processing terminal device is capable of inputting data by a touch pen method from a display unit. However, in order to input character / drawing information or video information on paper, a scanner or a digital camera as described above is used. It is necessary to connect to a peripheral device for reading the image. Therefore, the portability of the information processing terminal device has been impaired. In addition, it imposes an economic burden on the user to purchase peripheral equipment.

[0007] The active matrix type liquid crystal display device is also used for a display unit of a TV conference system, a TV phone, an Internet terminal, and the like. In these systems and terminals, cameras (C
Although the display unit and the reading unit (sensor unit) are separately manufactured and modularized, the manufacturing cost is high.

[0008] In addition, portability is the main feature of the portable information terminal device. Therefore, it is desired to reduce the volume as much as possible. In order to reduce this volume, various improvements such as downsizing of parts have been added,
At present, it is difficult to reduce the size of the battery portion serving as a power supply because of the limitation that the length of time for actually using the device cannot be sacrificed. Therefore, it has been desired not only to improve the battery, but also to suppress the power consumption of the terminal device itself, thereby reducing the volume of the battery component and securing a certain use time. It has been pointed out that most of this power consumption is due to the light sources required in liquid crystal displays.

An object of the present invention has been made in view of the above-mentioned problems, and has an object including a pixel matrix, an image sensor, and a peripheral circuit for driving them.
That is, an object of the present invention is to provide a new intelligent image recognition device integrated display device having both an image recognition function and a display function.

It is a further object of the present invention to manufacture a new intelligent semiconductor device at low cost by making the structure and manufacturing process of an image sensor compatible with the structure and manufacturing process of an active element. is there.

[0011]

In order to solve the above-mentioned problems, the present invention provides a semiconductor device and a peripheral drive circuit semiconductor device for a display pixel matrix portion for displaying an image,
A sensor unit for capturing image information is provided in the same panel. In this case, the sensor section has various effects by being provided on a substrate provided with active elements for display. On the other hand, it can also be achieved by providing it on the counter substrate side that constitutes the display panel.

A display device for displaying an image has a structure in which a pixel which is a minimum unit of a screen has both an electrode portion for reflecting light and an electrode portion for transmitting light. The configuration of the present invention is as described below.

According to one embodiment of the present invention, an active matrix substrate having a plurality of pixel portions having active elements and arranged in a matrix, and using a reflective material and a translucent material as electrodes of the pixel portions And a plurality of sensor units arranged in a matrix on the active matrix substrate, wherein the sensor unit has a photoelectric conversion element, and when reading an external image, The above object is achieved by adopting a configuration in which information is read out using light transmitted through the translucent material.
In addition, by forming the active element at this time by a TOP (top) gate type TFT or a bottom gate type TFT, the above object is achieved according to each embodiment.

According to one embodiment, a plurality of pixel portions having active elements and arranged in a matrix are provided;
A display device, comprising: an active matrix substrate using a reflective material and a translucent material as electrodes of the pixel portion; and a plurality of sensor portions arranged in a matrix on a counter substrate forming a display panel. And the sensor unit comprises:
The above object is achieved by including a photoelectric conversion element and reading information using light transmitted through the translucent material when reading an external image. In addition, the above object is achieved by providing a structure in which a color filter is provided over the counter substrate in the above structure.

According to one embodiment, a plurality of pixel portions having active elements and arranged in a matrix are provided.
An active matrix substrate using a reflective material and a translucent material as electrodes of the pixel portion, and a plurality of sensor portions arranged in a matrix on the active matrix substrate, a display device, The sensor part is
The above object is achieved by including a photoelectric conversion element, wherein at least a part of the photoelectric conversion element is extended so as to overlap with the active element.

According to one embodiment, an active matrix substrate having active elements and a plurality of pixel portions arranged in a matrix, and a plurality of sensor portions arranged in a matrix on the active matrix substrate are provided. The above object is attained by the pixel device provided in the pixel also serving as a capacitor for image recognition provided in the sensor unit. Furthermore, by using a reflective material and a translucent material as electrodes of the pixel portion in such a configuration, the above object is achieved. Further, a reflective material and a translucent material are used as electrodes of the pixel portion, and these materials also serve as at least a part of an electrode constituting a capacitance portion for image recognition provided in the sensor portion. Thereby, the above object is achieved.

A typical embodiment of the apparatus of the present invention will be described below with reference to the drawings and the like. Note that the image recognition device-integrated display device of the present invention is not limited to the embodiments described below.

Referring to FIG. FIG. 1 shows an example of a circuit configuration that can be applied to an image recognition device-integrated display device of the present invention. For convenience of explanation, in FIG.
Although the circuit configuration of a semiconductor device having (vertical × horizontal) pixels is shown, many pixels are actually formed on an actual substrate. For example, in the case of a display device of the VGA standard, the number of pixels is 640 × 480, and that of the SVGA standard is 800 ×
600. Peripheral drive circuits are simply represented by blocks.

Reference numeral 101 denotes a pixel TFT; 102, a liquid crystal;
3 is an auxiliary capacitor, 104 is a sensor TFT, 105 is a photodiode PD, 106 is an auxiliary capacitor, 107 is a signal amplification TFT, 108 is a reset TFT, 109 and 11
0 is an analog switch. Reference numeral 120 denotes a bias TFT, 121 denotes a transfer TFT, 122 denotes a sample and hold capacitor, 123 denotes a discharge TFT, 124 denotes a final buffer amplification TFT, and 125 denotes a final buffer bias TFT. The circuit constituted by these 101 to 108 is called a matrix circuit.

Further, 101 and 103 are pixel units A, 1
04, 105, 106, 107 and 108 are referred to as a sensor section B. 111 is a sensor output signal line, and 112 is an image input signal line. 113 and 114 are fixed potential lines. Reference numeral 115 denotes a pixel source signal line side driving circuit, 116 denotes a pixel gate signal line side driving circuit, 117 denotes a sensor horizontal driving circuit, and 118 denotes a sensor vertical driving circuit.

The display device integrated with the image recognition device of the present invention is
When displaying an image, an image signal (gradation voltage) input from an image input signal line is supplied to a pixel TFT by a pixel source signal line side driving circuit 115 and a pixel gate signal line side driving circuit 116, The liquid crystal sandwiched between the pixel electrode connected to the TFT and the counter electrode can be driven to display an image. In FIG. 1, the pixel source signal line side driving circuit 115 and the pixel gate signal line side driving circuit 1
Reference numeral 16 denotes an analog drive circuit that handles analog image signals, but is not limited to this. That is, a digital drive circuit equipped with a D / A conversion circuit that handles digital video signals may be used.

Further, in the display device integrated with the image recognition device of the present invention, the incident external image information (optical signal) is read by the photodiode PD105, which is a photoelectric conversion element, and is converted into an electric signal. An image is captured by the sensor vertical drive circuit 118. This video signal is taken into another peripheral circuit (memory, CPU, etc.) from the sensor output signal line 111.

FIGS. 2 and 3 show the state in which the display device integrated with the image recognition device of the present invention is disassembled into constituent parts. In FIGS. 2 and 3, the intervals between the components are shown large for convenience of explanation. 2 and 3, the semiconductor device of the present invention is used as TN (twisted nematic) mode normally white (white display when no voltage is applied). Also,
A liquid crystal display method of another mode such as an STN mode, an ECB mode, an FLC or AFLC liquid crystal, or a birefringent mode using a so-called V-shaped liquid crystal can also be used. Further, it may be used in normally black (black display when no voltage is applied).

Referring to FIG. FIG. 2 shows a case where the semiconductor device of the present invention is used in an image display mode. Reference numeral 201 denotes an active matrix substrate.
, A pixel source signal line side driving circuit 201-2, a pixel gate signal line side driving circuit 201-3, a sensor horizontal driving circuit 201-4, a sensor vertical driving circuit 201-5, and the like. Peripheral circuit 201-6
have. Note that an alignment film and the like are formed on the upper surface of the active matrix substrate, but are not shown here.

The fact that it is not possible to actually indicate due to the schematic diagram is 2
A liquid crystal material exists in the region indicated by 02. 2
Numeral 03 denotes a counter substrate having a transparent electrode and an alignment film (both not shown). Reference numerals 204 and 205 denote polarizing plates, which are arranged so as to cross each other. 206 is a backlight. Reference numeral 207 schematically shows a user (eye), and shows a state where the user is observing the semiconductor device of the present invention from above. Note that a glass substrate, a plastic substrate, or the like is provided above the upper polarizing plate 207 in order to prevent the polarizing plate from being scratched or dusted (not shown).

The active matrix substrate 201 is provided with a pixel electrode for display. FIG. 4 shows this pixel portion. Normally, the pixel electrode is made of a light-transmitting ITO or the like, but in the present invention, a light-transmitting material and a reflective material such as aluminum are used to partially pass light through the pixel. And a part for reflecting light.

The layout of the light-transmitting portion in the pixel can be arbitrarily determined, but the position and position of the portion can be determined in accordance with the characteristics required of the image recognition device-integrated display device of the present invention.
The area ratio can be changed. FIG. 4 shown as an example is shown in FIG.
It is an example of × 2 pixels. In FIG. 4, the reflective electrode 302 for display is used.
A transmission electrode 305 for display and a window 303 for sensor are arranged so as to sandwich it. With such an arrangement, the light transmitting window 303 for the sensor is surrounded by the reflective electrode 302 and the BM 304 formed so as to surround the pixel, so that light to the sensor does not sneak from another area when reading an image. Reading errors can be reduced.

When the semiconductor device of the present invention is used in the image display mode, it is based on a supplied video signal (a signal stored in a built-in memory or the like or a signal supplied from the outside). A gradation voltage is supplied to the pixel TFT to drive the liquid crystal 202. Note that color display can be performed using a color filter. In addition, when display is performed without turning on the backlight 206, the backlight 206 can be used as a reflective display panel using the reflective electrode 302, and power consumption can be reduced. In addition, when the display is not sufficiently visible in the reflection mode when the use condition is dark, the backlight can be turned on and display can be performed by the transmission electrode 305, and the power consumption of the panel can be adjusted as necessary.

Next, reference is made to FIG. FIG. 3 shows a case where the image recognition device-integrated display device of the present invention is used in the image reading mode. Refer to the description of FIG. 2 for the components constituting the device of the present invention. Reference numeral 301 denotes an image reading object, such as a business card or a photograph. Further, in FIG. 3, the image reading object 301 is shown at an interval from a polarizing plate (or a glass substrate or a plastic substrate (not shown)), but it is preferable that the image reading object 301 is arranged so as to be in close contact with the polarizing plate.

When the image recognition device-integrated display device of the present invention is used in the image reading mode, no voltage is applied to the pixel TFT, and the display by all the pixels is set to white display. Thus, the surface of the image reading target 301 is irradiated with the light of the backlight 206 through the transmission electrode 305 for display. Light applied to the surface of the image reading target (document) 301 is reflected on the surface of the image reading target 301.

At this time, the reflected light has image information of the object 301 to be read. The reflected light passes through a glass substrate (not shown), a polarizing plate, a counter substrate, and liquid crystal, passes through a sensor transmission window 303 in a pixel portion, and is aligned with the active matrix circuit of the active matrix substrate. Is detected by the photodiode PD in the sensor section B, and is converted into an electric signal.

The image information converted into the electric signal is taken out from the sensor output signal line as described above and stored in a memory (which may be formed on the same substrate or may be arranged outside). Is done. Thus, the image of the image reading object 301 is captured.

Also, the case where a business card or a photograph is brought into close contact with the image recognition device-integrated display device of the present invention has been described.
It is also possible to capture a scenery, a person image, or the like in the sense of a digital camera and capture the image. In this case, the image is recognized without turning on the backlight 206.

The image converted into an electric signal by the sensor unit B can be displayed almost in real time by being displayed by the pixel unit A. Also,
The pixel portion A may be configured to be capable of displaying data from outside the image recognition device-integrated display device.

Next, the cross-sectional structure of the active matrix substrate constituting the image recognition device integrated display device of the present invention will be described. Please refer to FIG. The active matrix substrate of the image recognition device-integrated display device has a pixel portion A and a sensor portion B in one pixel as shown in FIG.

In FIG. 5, the pixel TFT and the sensor TF
T is shown. A light-shielding film 404 of the pixel TFT is provided on the substrate 400, and has a structure for protecting the pixel TFT from light incident from the back surface. Further, as shown in the figure, a configuration may be adopted in which a light shielding film 405 is provided on the sensor TFT on the sensor section B side. Further, the reset T of the sensor unit B is performed.
The FT or the TFT for signal amplification (both not shown) may be provided with a light shielding film (not shown). Further, these light-shielding films may be provided directly on the rear surface side of the substrate 400.

On the light shielding films 404 and 405, the base film 40 is formed.
1 is formed, the pixel TFT of the display section A, the sensor TFT of the sensor section B, the signal amplification TFT, and the reset TF
T and TFTs constituting a driving circuit and a peripheral circuit are simultaneously manufactured. Note that here, the back surface of the substrate 400
It refers to the substrate surface on which the TFT is not formed.
The configuration of these TFTs may be a top gate type TFT or a bottom gate type TFT. FIG. 5 shows a case of a top gate type TFT as an example.

Then, a lower electrode 420 connected to the electrode 419 of the sensor TFT is provided. This lower electrode 420
Forming the lower electrode of the photodiode (photoelectric conversion element),
It is formed in a pixel area other than the upper part of the pixel TFT. The photoelectric conversion layer 421 is provided on the lower electrode 420, and the upper electrode 422 is further provided thereon, whereby a photodiode is completed. Note that a light-transmitting electrode is used for the upper electrode 422.

On the other hand, the pixel TFT in the pixel portion is
A pixel light-transmitting electrode 424 connected to the pixel. Further, a reflective electrode 425 is formed in contact with this electrode. In FIG. 5, the reflective electrode is laminated on the light-transmitting electrode 424. However, the light-transmitting electrode 424 is patterned and a part of the reflective electrode 425 is formed.
And a structure having only a reflective electrode and a translucent electrode does not exceed the scope of the present invention.

The pixel translucent electrode 424 may be configured to cover the sensor section B and the wiring, and the positions of the reflective electrode and the translucent electrode can be arbitrarily arranged as described above.
In FIG. 5, the size of the pixel portion A and the size of the sensor portion B are different from the actual size for the sake of explanation. This size is a design matter that is changed according to the specifications of the image recognition device integrated display device as described above. When the wiring is covered, the display pixel capacitance is formed by using the insulating film between the wiring and the pixel electrode as a dielectric.

The manufacturing process of the active element applicable to the device of the present invention is substantially the same as that of the conventional display except that a manufacturing process of a photosensor as a photoelectric conversion element is added. The configuration of this photosensor is formed by laminating or contacting different conductive types such as PIN, PI, and NI, or by laminating or contacting different materials such as Schottky or heterojunction, or a semiconductor material. You can use your own light sensitivity.

Thus, since a conventional manufacturing process can be used, it can be manufactured easily and at low cost. In addition, the device manufactured according to the present invention does not change in shape and size from a conventional panel even if it has a sensor function. Therefore, size and weight can be reduced.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the semiconductor device of the present invention will be described below, but the present invention is not limited to the following embodiment.

Example 1 In this example, a manufacturing process of one embodiment of the present invention will be described with reference to FIGS. In the following description, a pixel TFT and a sensor TFT are representatively described, but a reset TFT, a signal amplification TFT, an analog switch, a driving circuit, and a P-channel TFT forming a peripheral circuit.
And an N-channel type TFT can be simultaneously manufactured. Further, the arrangement of the pixel translucent electrode, the pixel reflection electrode, and the sensor window was performed such that the arrangement was planar as shown in FIG.

Referring to FIG. First, a base film 401 is formed on the entire surface of the transparent substrate 400. As the transparent substrate 400, a glass substrate or a quartz substrate having transparency can be used. As the base film 401, a silicon oxide film was formed to a thickness of 150 nm by a plasma CVD method. In the present embodiment, before this base film forming step, a light-shielding film 404 for protecting the pixel TFT from light from the back surface and a sensor TF
A light-shielding film 405 for protecting T from light from the back surface was provided. This light-shielding film may be made of a metal material such as Ta, W, Cr or the like, a compound thereof, Si, silicide, or a laminate of these and a metal.

Next, an amorphous silicon film was formed to a thickness of 30 to 100 nm, preferably 30 nm by a plasma CVD method, and then irradiated with excimer laser light to form a polycrystalline silicon film. As a method for crystallizing the amorphous silicon film, a thermal crystallization method called SPC, R
These may be further combined using a TA method, a method using thermal crystallization and laser annealing, or the like.

Next, the polycrystalline silicon film is patterned
An island-shaped semiconductor layer 402 constituting a source region, a drain region, a channel formation region of a pixel TFT, and a sensor T
An island-shaped semiconductor layer 403 which forms a source region, a drain region, and a channel formation region of the FT is formed. Then, a gate insulating film 406 which covers these semiconductor layers is formed. The gate insulating film 406 is formed to have a thickness of 100 nm by a plasma CVD method using silane (SiH ₂ ) and N ₂ O as a source gas (FIG. 6A).

Next, a conductive film is formed. Here, aluminum was used as the conductive film material, but Ta, W, T
It may be a film containing aN, WN, titanium, or silicon as a main component, or a stacked film thereof. In this embodiment, the aluminum film is formed in a thickness of 200 to 500 by sputtering.
It is formed to a thickness of nm, typically 300 nm. In order to suppress generation of hillocks and whiskers, scandium (Sc), titanium (Ti), and yttrium (Y) are contained in the aluminum film in an amount of 0.04 to 1.0% by weight.

Next, a resist mask is formed, the aluminum film is patterned to form an electrode pattern, and a pixel TFT gate electrode 407 and a sensor TFT gate electrode 408 are formed.

Next, an offset structure is formed by a known method. Alternatively, the LDD structure may be formed by a known method. Thus, impurity regions (source / drain regions) 409, 410, 412, 413 and channel regions 411, 414 are formed (FIG. 6).
(B)). In FIG. 6, only the sensor TFT and the pixel TFT which are N-channel TFTs are shown for convenience of description, but a P-channel TFT is also manufactured.
As an impurity element, P (phosphorus) or As (arsenic) is used for an N channel type, and B (boron) or Ga is used for a P type.
(Gallium) may be used.

Then, a first interlayer insulating film 415 is formed, and contact holes reaching the impurity regions 409, 410, 412, 413 are formed. Thereafter, a metal film is formed and patterned to form electrodes 416 to 419. At this time, wiring for connecting a plurality of TFTs is formed simultaneously.

In this embodiment, the first interlayer insulating film 415 is formed of a 500 nm thick silicon nitride film. As the first interlayer insulating film, a silicon oxide film or a silicon nitride film can be used in addition to the silicon nitride film. Further, a multilayer film of these insulating films may be used.

In this embodiment, a laminated film composed of a titanium film, an aluminum film, and a titanium film is formed by a sputtering method as a metal film serving as a starting film for electrodes and wirings. These film thicknesses are 100 nm, 300 nm, and 100 n, respectively.
m. Through the above process, the pixel TFT and the sensor TFT are completed at the same time (FIG. 6C).

Next, the first interlayer insulating film 415 and the sensor T
A metal film is formed in contact with the drain electrode 419 of the FT.
A metal film is formed and patterned to form a lower electrode 420 of the photoelectric conversion element. In this embodiment, aluminum is used for this metal film by sputtering, but other metals can be used. For example, a stacked film including a titanium film, an aluminum film, and a titanium film may be used. In this embodiment, the wiring 419 for the TFT and the electrode 420 for the sensor are manufactured in different steps, but they may be formed in the same step.

In this case, the sensor electrode 420 can be easily formed by changing the mask pattern for forming 419. Rather, it is more convenient to create them at the same time because the cost can be reduced by reducing the number of processes and the yield can be improved. In addition, in the case of a liquid crystal display, if the active matrix substrate has severe irregularities, it may cause disturbance of liquid crystal alignment and the like. Therefore, it is more preferable to form 419 and 420 at the same time.

Referring to FIG. Next, an amorphous silicon film containing hydrogen (hereinafter, a-S
i: H film) is formed over the entire surface of the substrate and patterned to form a photoelectric conversion layer 421 (FIG. 7A).

Next, a transparent conductive film is formed on the entire surface of the substrate.
In this embodiment, a 200 nm thick ITO is used as the transparent conductive film.
Is formed by a sputtering method. The transparent conductive film is patterned to form an upper electrode 422 (FIG. 7A).

Then, a second interlayer insulating film 423 is formed. It is preferable to form a resin film of polyimide, polyamide, polyimide amide, acrylic, or the like as an insulating film forming the second interlayer insulating film because a flat surface can be obtained. Alternatively, the second interlayer insulating film has an upper layer formed of the above resin film, a lower layer formed of silicon oxide, silicon nitride,
A single layer or a multilayer film of an inorganic insulating material such as silicon oxynitride may be formed. In this embodiment, the thickness of the insulating film is 0.7 μm.
m was formed on the entire surface of the substrate (FIG. 7).
(B)).

Further, a contact hole reaching the drain electrode 416 is formed in the second interlayer insulating film 423. Again, a light-transmitting film containing zinc oxide as a main component is formed over the entire surface of the substrate, and is patterned to form a pixel light-transmitting electrode 424 connected to the pixel TFT. Next, aluminum is formed on the entire surface as a reflective electrode material to a thickness of 200 nm over the entire surface, and is etched by a predetermined mask pattern to form a pixel reflective electrode
Form 30. The translucent electrode and the reflective electrode may come into contact with each other or react during etching with an acid solution. In order to prevent these, attention must be paid to the combination of electrode materials. In this embodiment, ZnO—Al is used.
TO-Ti, a mixture of ITO and zinc and Al, Ti, Cr
Or, a mixture with these mixtures or a laminate is conceivable.

Through the above steps, the active matrix substrate shown in FIG. 7C is completed.

Then, the active matrix substrate and the opposing substrate are bonded together with a sealant, and liquid crystal is sealed to complete a display device integrated with an image recognition device. This counter substrate is formed by forming a transparent conductive film and an alignment film on a transparent substrate. In addition, a black mask and a color filter can be provided as needed.

The color filter 50 for assembling the liquid crystal panel with the active matrix substrate 400 having the sensor unit and the pixel unit formed on the same substrate, thus manufactured.
The opposing substrate 500 with 2 is attached to form a liquid crystal panel. This schematic is shown in FIG. With such a configuration, it is possible to realize an image recognition device-integrated display device that is not bulky and has excellent portability. The method for displaying the image and recognizing the image is as described above.

In particular, the display device can be selectively used in the reflection mode and the transmission mode depending on the place where it is to be used, so that the power consumption can be suppressed, and at the time of image recognition, the display device has passed through the translucent electrode of the pixel electrode. An original can be read by light from the backlight 501. As a result, a PDA (portable personal terminal) incorporating an image recognition device-integrated display device can be suppressed to a very small volume, and a function of reading information such as a business card, a photograph or a digital camera can be realized. .

A sheet 512 for providing an optical effect can be provided between the polarizing plate 511 and the opposing substrate.
More light can be used than when an optical fiber plate is provided as this sheet, and when a lens array sheet is provided, light from a document can be imaged on a sensor to further reduce reading errors.

The embodiments of the present invention will be described in detail with reference to the following examples. (Embodiment 2) An example of forming a TFT element applicable to an image recognition device-integrated display device of the present invention will be described with reference to FIGS. Here, the pixel TFT and the storage capacitor of the pixel portion and the TFT of the driving circuit provided around the display area are used.
Will be described in detail according to the steps.

Referring to FIG. 8A, a substrate 601 is made of a glass substrate such as barium borosilicate glass or alumino borosilicate glass typified by Corning # 7059 glass or # 1737 glass, and polyethylene terephthalate (PET). ), Polyethylene naphthalate (P
EN), a plastic substrate having no optical anisotropy such as polyethersulfone (PES) can be used. When a glass substrate is used, heat treatment may be performed in advance at a temperature lower by about 10 to 20 ° C. than the glass strain point.

Then, a base film 602 such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed on the surface of the substrate 601 where a TFT is to be formed, in order to prevent impurity diffusion from the substrate 601. For example, plasma CV
SiH ₄ in Method D, NH _3, silicon oxynitride is formed from N ₂ O film 602a of 10 to 200 nm (preferably 50
To 100 nm), and a silicon oxynitride hydride film 602 b similarly made of SiH ₄ and N ₂ O is formed to a thickness of 50 to 200 nm.
(Preferably 100 to 150 nm).

The silicon oxynitride film is a conventional parallel plate type
It is formed by a plasma CVD method. Silicon oxynitride
The film 602a is made of SiH_FourTo 10 SCCM, NH_ThreeTo 100 SCC
M, N _TwoO was introduced into the reaction chamber at 20 SCCM, and the substrate temperature was 3
25 ° C, reaction pressure 40Pa, discharge power density 0.41W / cm
2. The discharge frequency was set to 60 MHz. On the other hand, hydrogen oxynitride
The recon film 602b is made of SiH_FourTo 5 SCCM, N_TwoO to 120
SCCM, H_TwoInto the reaction chamber as 125 SCCM,
400 ° C, reaction pressure 20Pa, discharge power density 0.41W /
cm^TwoAnd the discharge frequency was 60 MHz. These films are heated at the substrate temperature.
Continuous formation by changing the reaction gas only by switching the reaction gas
You can also.

The silicon oxynitride film 602a thus manufactured has a density of 9.28 × 10 ²² / cm ³ , 7.13% of ammonium hydrogen fluoride (NH ₄ HF ₂ ) and ammonium fluoride (NH ₄ HF ₂ ). 20% of a mixed solution containing 15.4% of NH ₄ F) (trade name: LAL500, manufactured by Stella Chemifa).
The etching rate at a temperature of ° C. is as low as about 63 nm / min, and the film is dense and hard. Use of such a film as a base film is effective in preventing an alkali metal element from a glass substrate from diffusing into a semiconductor layer formed thereover.

Next, 25 to 80 nm (preferably 30 to 80 nm)
Semiconductor layer 603 having a thickness of 60 nm and having an amorphous structure.
a is formed by a known method such as a plasma CVD method or a sputtering method. For example, an amorphous silicon film is formed to a thickness of 55 nm by a plasma CVD method. The semiconductor film having an amorphous structure includes an amorphous semiconductor film and a microcrystalline semiconductor film, and a compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film may be used.

The base film 602 and the amorphous semiconductor layer 60
With 3a, both can be formed continuously. example
For example, as described above, the silicon oxynitride film
Continuous silicon hydride film 602b by plasma CVD
After the film formation, the reaction gas is SiH _Four, N_TwoO, H_TwoFrom Si
H_FourAnd H_TwoOr SiH_FourOnce you switch to only the atmosphere
It can be formed continuously without exposure to the atmosphere. As a result, oxidation
Preventing contamination of the surface of the hydrogenated silicon nitride film 602b
Is possible, and characteristic variations and threshold
Variations in the value voltage can be reduced.

Then, a crystallization step is performed to form a crystalline semiconductor layer 603b from the amorphous semiconductor layer 603a. Laser annealing, thermal annealing (solid phase growth), or rapid thermal annealing (RTA)
Law) can be applied. When a glass substrate or a plastic substrate having low heat resistance as described above is used, it is particularly preferable to apply a laser annealing method. RT
In the method A, an infrared lamp, a halogen lamp, a metal halide lamp, a xenon lamp, or the like is used as a light source.

Alternatively, the crystalline semiconductor layer 603b can be formed by a crystallization method using a catalytic element according to the technique disclosed in Japanese Patent Application Laid-Open No. Hei 7-130652. In the crystallization step, first, it is preferable to release hydrogen contained in the amorphous semiconductor layer, and heat treatment is performed at 400 to 500 ° C. for about 1 hour to reduce the amount of hydrogen contained to 5 atom% or less. This makes it possible to prevent roughening of the film surface, which is good.

When crystallization is performed by laser annealing, a pulse oscillation type or continuous emission type excimer laser or argon laser is used as the light source. When a pulse oscillation type excimer laser is used, laser annealing is performed by processing the laser beam into a linear shape. Laser annealing conditions are appropriately selected by the practitioner, for example,
The laser pulse oscillation frequency is 30 Hz, and the laser energy density is 100 to 500 mJ / cm ² (typically 300
４００400 mJ / cm ² ). Then, a linear beam is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear beam at this time is set to 80 to 98%. In this manner, as shown in FIG.
3b can be obtained.

Then, a resist pattern is formed on the crystalline semiconductor layer 603b using the photomask 1 (PM1) by using a photolithography technique, and the crystalline semiconductor layer is divided into islands by dry etching. The semiconductor layers 604 to 608 are formed. For dry etching, a mixed gas of CF ₄ and O ₂ is used.

In order to control the threshold voltage (Vth) of the TFT, an impurity element imparting a p-type is added to such an island-like semiconductor layer in an amount of about 1 × 10 ^{16 to} 5 × 10 ¹⁷ atoms / cm ³ . The concentration may be added to the entire surface of the island-shaped semiconductor layer. The impurity element imparting p-type to the semiconductor includes boron (B),
Elements of Group 13 of the periodic table, such as aluminum (Al) and gallium (Ga), are known.

As the method, an ion implantation method or an ion doping method can be used, but the ion doping method is suitable for treating a large area substrate. In the ion doping method, diborane (B ₂ H ₆ ) is used as a source gas and boron (B) is added. The implantation of such an impurity element is not always necessary and may be omitted. However, it is a method preferably used for keeping the threshold voltage of the n-channel TFT within a predetermined range.

The gate insulating film 609 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by a plasma CVD method or a sputtering method. For example, 120 nm
Of a silicon oxynitride film. A silicon oxynitride film formed by adding O ₂ to SiH ₄ and N ₂ O is a preferable material for this application because the fixed charge density in the film is reduced. Needless to say, the gate insulating film is not limited to such a silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure (FIG. 8C).

As shown in FIG. 8D, the gate insulating film 6
09, a heat-resistant conductive layer for forming a gate electrode is formed. The heat-resistant conductive layer may be formed as a single layer, or may be formed as a multilayer structure including a plurality of layers such as two layers or three layers as necessary. For example, a structure in which a conductive layer (A) 610 made of a conductive nitride metal film and a conductive layer (B) 611 made of a metal film are stacked using such a heat-resistant conductive material is preferable. The conductive layer (B) 611 includes tantalum (Ta), titanium (Ti), molybdenum (Mo),
An element selected from tungsten (W), an alloy containing the above element as a main component, or an alloy film combining the above elements (typically, a Mo—W alloy film or a Mo—Ta alloy film) may be used. The conductive layer (A) 610 is made of tantalum nitride (T
aN), tungsten nitride (WN), titanium nitride (Ti
N) film, molybdenum nitride (MoN) or the like.

As the conductive layer (A) 610, tungsten silicide, titanium silicide, or molybdenum silicide may be used. It is preferable to reduce the impurity concentration of the conductive layer (B) 611 in order to reduce the resistance. In particular, the oxygen concentration is preferably 30 ppm or less. For example, tungsten (W) has an oxygen concentration of 30.
A specific resistance of 20 μΩcm or less could be realized by setting the content to ppm or less.

The conductive layer (A) 610 has a thickness of 10 to 50 nm (preferably 20 to 30 nm), and the conductive layer (B) 611 has a thickness of 200 to 400 nm (preferably 250 to 350 nm).
It is good. In the case where W is used as a gate electrode, an argon (Ar) gas and a nitrogen (N ₂ ) gas are introduced by sputtering using W as a target, and the conductive layer (A) 611 is made of tungsten nitride (WN) of 50 nm. The conductive layer (B) 610 is formed with W to a thickness of 250 nm.

As another method, the W film can be formed by thermal CVD using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to lower the resistance in order to use it as a gate electrode.
It is desirable to set the value to μΩcm or less. The resistivity of the W film can be reduced by enlarging the crystal grains. However, when there are many impurity elements such as oxygen in W, crystallization is inhibited and the resistance is increased. Thus, in the case of using the sputtering method, a W target having a purity of 99.9999% is used, and further, the W film is formed with sufficient care so as not to mix impurities from the gas phase during film formation. 9-20μ
Ωcm can be realized.

On the other hand, a TaN film is formed on the conductive layer (A) 610.
When a Ta film is used for the conductive layer (B) 611, the conductive layer (B) 611 can be similarly formed by a sputtering method. TaN film is T
The target film a is formed using a mixed gas of Ar and nitrogen as a sputtering gas, and the Ta film uses Ar as a sputtering gas. When an appropriate amount of Xe or Kr is added to these sputter gases, the internal stress of the film to be formed can be relaxed and the film can be prevented from peeling.

The resistivity of the α-phase Ta film is about 20 μΩcm and can be used for the gate electrode.
The resistivity of the film was about 180 μΩcm, and was not suitable for use as a gate electrode. Since the TaN film has a crystal structure close to the α-phase, an α-phase Ta film was easily obtained by forming a Ta film thereon. Although not shown, the conductive layer (A) 61
It is effective to form a silicon film doped with phosphorus (P) with a thickness of about 2 to 20 nm below 0. Accordingly, the adhesion of the conductive film formed thereover is improved and oxidation is prevented, and at the same time, a small amount of an alkali metal element contained in the conductive layer (A) 610 or the conductive layer (B) 611 is added to the gate insulating film 609. Spreading can be prevented. In any case, the conductive layer (B) 611 has a resistivity of 10 to 50.
It is preferable to set it in the range of μΩcm.

Next, using the photomask 2 (PM2),
The resist masks 612 to 617 are formed by using the photolithography technique, and the conductive layer (A) 610 and the conductive layer (B) 611 are collectively etched to form the gate electrode 61.
8 to 622 and a capacitor wiring 623 are formed. Gate electrode 6
18 to 622 and the capacitor wiring 623 are formed of a conductive layer (A) 618a to 622a and a conductive layer (B) 618a.
b to 622b are integrally formed (FIG. 9).
(A)).

The method of etching the conductive layer (A) and the conductive layer (B) may be appropriately selected by a practitioner. However, when the conductive layer (A) and the conductive layer (B) are formed of a material containing W as a main component as described above, It is desirable to apply a dry etching method using high-density plasma in order to perform etching at high speed and with high accuracy.

As one of the techniques for obtaining high-density plasma,
Inductively Coupled Plasma (IC)
P) An etching apparatus is preferably used. The etching method of W using an ICP etching apparatus is as follows.
Two gases, F ₄ and Cl ₂ , were introduced into the reaction chamber and the pressure was 0.5
To 1.5 Pa (preferably 1 Pa), and a high frequency (13.56 MHz) power of 200 to 1000 W is applied to the inductive coupling portion. At this time, the stage on which the substrate is placed is 20
By applying a high frequency power of W and charging to a negative potential by a self-bias, positive ions are accelerated and anisotropic etching can be performed. By using an ICP etching apparatus, even a hard metal film such as W can obtain an etching rate of 2 to 5 nm / sec.

In order to perform etching without leaving any residue, it is preferable to increase the etching time by about 10 to 20% and perform over-etching. At this time, however, it is necessary to pay attention to the etching selectivity with the base.
For example, since the selectivity of the silicon oxynitride film (gate insulating film 609) to the W film is 2.5 to 3, the exposed surface of the silicon oxynitride film is etched by about 20 to 50 nm by such an over-etching process. Has been substantially thinner.

Then, in order to form an LDD region in the n-channel TFT, a step of adding an impurity element imparting n-type (n ^- doping step) was performed. Here, the gate electrode 6
Using 18 to 622 as a mask, an impurity element imparting n-type in a self-aligned manner was added by an ion doping method. The concentration of phosphorus (P) added as an impurity element imparting n-type is 1 ×
It is added in a concentration range of 10 ^{16 to} 5 × 10 ¹⁹ atoms / cm ³ .
Thus, low-concentration n-type impurity regions 624 to 629 are formed in the island-shaped semiconductor layer as shown in FIG.

Next, in the n-channel TFT, a high-concentration n-type impurity region functioning as a source region or a drain region was formed (n ⁺ doping step). First, using a photomask 3 (PM3), a resist mask 63 is used.
Nos. 0 to 634 were formed, and an n-type impurity element was added to form high-concentration n-type impurity regions 635 to 640.
Ion doping method using phosphine (PH ₃ ) such that phosphorus (P) is used as an impurity element imparting n-type and its concentration is in a concentration range of 1 × 10 ²⁰ to 1 × 10 ²¹ atoms / cm ^3. (FIG. 9 (C)).

Then, high-concentration p-type impurity regions 644 and 645 serving as a source region and a drain region are formed in the island-like semiconductor layers 604 and 606 forming the p-channel TFT. Here, an impurity element imparting p-type is added using the gate electrodes 618 and 620 as a mask, and a high-concentration p-type impurity region is formed in a self-aligned manner. At this time, the island-shaped semiconductor films 605, 607, and 6 forming the n-channel TFT are formed.
08, resist masks 641 to 643 are formed using photomask 4 (PM4), and the entire surface is covered.

The high-concentration p-type impurity regions 644 and 645 are formed by an ion doping method using diborane (B ₂ H ₆ ).
The boron (B) concentration in this region is 3 × 10 ^{20 to} 3 × 10 ^21.
atoms / cm ³ (FIG. 9D). Phosphorus (P) is added to the high concentration p-type impurity regions 644 and 645 in the previous step, and the high concentration p-type impurity
44a and 645a are 1 × 10 ²⁰ to 1 × 10 ²¹ atoms / c
At the concentration of m ³ , the high concentration p-type impurity regions
Contains 1 × 10 ^{16 to} 5 × 10 ¹⁹ atoms / cm ³ , but by increasing the concentration of boron (B) added in this step from 1.5 to 3 times, There was no problem in functioning as the source and drain regions of the p-channel TFT.

After that, as shown in FIG. 10A, a protective insulating film 646 is formed over the gate electrode and the gate insulating film. The protective insulating film may be formed using a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a stacked film including a combination thereof. In any case, the protective insulating film 64
6 is formed from an inorganic insulating material. The thickness of the protective insulating film 646 is 100 to 200 nm.

Here, when a silicon oxide film is used, tetraethyl orthosilicate (TEOS) and O ₂ are mixed by plasma CVD, the reaction pressure is 40 Pa, the substrate temperature is 300 to 400 ° C., and the high frequency (13.56MHz) Power density 0.5 ~ 0.8W
/ cm ² and can be formed by discharging. In the case of using a silicon oxynitride film, Si
A silicon oxynitride film formed from H ₄ , N ₂ O, and NH ₃ , or a silicon oxynitride film formed from SiH ₄ , N ₂ O may be used.

In this case, the manufacturing conditions are as follows:
0 Pa, substrate temperature 300-400 ° C., high frequency (60 MHz
z) It can be formed at a power density of 0.1 to 1.0 W / cm ² . Alternatively, a hydrogenated silicon oxynitride film formed from SiH ₄ , N ₂ O, and H ₂ may be used. Similarly, a silicon nitride film can be formed from SiH ₄ and NH ₃ by a plasma CVD method.

Thereafter, a step of activating the impurity elements imparting n-type or p-type added at the respective concentrations is performed. This step is performed by a thermal annealing method using a furnace annealing furnace. In addition, a laser annealing method or a rapid thermal annealing method (RTA method) can be applied. In the thermal annealing method, the oxygen concentration is 1 ppm or less,
Preferably in a nitrogen atmosphere of 0.1 ppm or less 400 ~
The heat treatment is performed at 700 ° C., typically 500 to 600 ° C. In this embodiment, the heat treatment is performed at 550 ° C. for 4 hours.
In the case where a plastic substrate having a low heat-resistant temperature is used as the substrate 601, a laser annealing method is preferably applied (FIG. 10B).

After the activation step, an additional 3 to 100%
1 to 12 at 300 to 450 ° C. in an atmosphere containing hydrogen
Heat treatment was performed for a long time to perform a step of hydrogenating the island-shaped semiconductor film. In this step, dangling bonds of 10 ¹⁶ to 10 ¹⁸ / cm ^{3 in} the island-like semiconductor film are terminated by thermally excited hydrogen. Plasma hydrogenation (using hydrogen excited by plasma) as another means of hydrogenation
May be performed.

When the activation and hydrogenation steps are completed,
The interlayer insulating film 147 made of an organic insulating material is
It is formed with an average thickness of 2.0 μm. As the organic resin material, polyimide, acrylic, polyamide, polyimide amide, BCB (benzocyclobutene), or the like can be used. For example, in the case of using a polyimide of a type that is thermally polymerized after being applied to a substrate, it is formed by firing at 300 ° C. in a clean oven. In the case of using acrylic, after using a two-pack type, mixing the main material and the curing agent, applying the entire surface of the substrate using a spinner, and preheating at 80 ° C. for 60 seconds on a hot plate. Then, it can be formed by firing in a clean oven at 250 ° C. for 60 minutes.

As described above, the surface can be satisfactorily flattened by forming the interlayer insulating film with the organic insulating material. In addition, since organic resin materials generally have a low dielectric constant, parasitic capacitance can be reduced. However, since it is hygroscopic and is not suitable as a protective film, it must be used in combination with a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or the like formed as the protective insulating film 646 as in this embodiment.

Thereafter, a resist mask having a predetermined pattern is formed using the photomask 5 (PM5), and a contact hole reaching the source region or the drain region formed in each of the island-shaped semiconductor films is formed. The formation of the contact hole is performed by a dry etching method. In this case, an interlayer insulating film made of an organic resin material is first etched by using a mixed gas of CF ₄ , O ₂ , and He as an etching gas, and then the protective insulating film 646 is etched by using the etching gas as CF ₄ and O _2. I do. Further, in order to increase the selectivity with the island-shaped semiconductor layer, the etching gas is CH
By etching the gate insulating film is switched to F _3, can satisfactorily form a contact hole.

Then, a conductive metal film is formed by a sputtering method or a vacuum evaporation method, a resist mask pattern is formed by a photomask 6 (PM6), and the source wirings 648 to 652 and the drain wirings 653 to 658 are etched.
To form Here, the drain wiring 657 functions as a pixel electrode. Although not shown, in this embodiment, this electrode is formed by forming a Ti film with a thickness of 50 to 150 nm, forming a contact with the semiconductor film forming the source or drain region of the island-shaped semiconductor layer, and forming the Ti film. Aluminum (Al) was formed in a thickness of 300 to 400 nm on the upper surface to form a wiring.

When hydrogenation was performed in this state, favorable results were obtained for improving the characteristics of the TFT. For example, 3 ~
The heat treatment may be performed at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 100% hydrogen, or the same effect is obtained by using a plasma hydrogenation method. In addition, such a heat treatment allows the protective insulating film 646 and the base film 602 to be formed.
Can be diffused into the island-shaped semiconductor films 604 to 608 for hydrogenation. In any case, the defect density in the island-shaped semiconductor films 604 to 608 is desirably 10 ¹⁶ / cm ³ or less.
It was sufficient to give about 0.1 atomic% (Fig. 10
(C)).

In this way, a substrate having a TFT of a driving circuit and a pixel TFT of a pixel portion can be completed on the same substrate by using six photomasks. The driving circuit includes a first p-channel TFT 700, a first n-channel TFT 701, a second p-channel TFT 702, and a second p-channel TFT 702.
N-channel type TFT 703 and the pixel portion has a pixel TFT 7
04, a storage capacitor 705 is formed. In this specification, such a substrate is referred to as an active matrix substrate for convenience.

First p-channel TFT 70 of drive circuit
0, the channel-forming region 70 is formed in the island-shaped semiconductor film 604.
6. Source region 707 including high-concentration p-type impurity region
a, 707b and a single drain structure having drain regions 708a, 708b. In the first n-channel TFT 701, an LD which does not overlap the channel formation region 709 and the gate electrode 619 in the island-shaped semiconductor film 605 is provided.
D region 710, source region 712, drain region 711
have. The length of this LDD region in the channel length direction is 1.0 to 4.0 μm, preferably 2.0 to 3.0 μm.
And By setting the length of the LDD region in the n-channel TFT in this way, a high electric field generated near the drain region is reduced, and the generation of hot carriers is prevented.
Deterioration of the TFT can be prevented.

Second p-channel TFT 70 of drive circuit
Similarly, the channel-forming region 7 is formed in the island-shaped semiconductor film 606.
13. Source region 714 made of high-concentration p-type impurity region
a, 714b and a single drain structure having drain regions 715a, 715b. In the second n-channel TFT 703, a channel formation region 716, LDD regions 717 and 718, a source region 720, and a drain region 719 are formed in the island-shaped semiconductor film 607. The LDD length of this TFT was also formed to be 1.0 to 4.0 μm. In the pixel TFT 704, the channel forming regions 721 and 722, the LDD regions 723 to
725, and source or drain regions 726 to 728. The length of the LDD region in the channel length direction is 0.5
４4.0 μm, preferably 1.5 to 2.5 μm.

Further, a storage capacitor 705 is formed from the capacitor wiring 623, an insulating film made of the same material as the gate insulating film, and a semiconductor layer 729 connected to the drain region 728 of the pixel TFT 704. In FIG. 10C, the pixel TF
Although T704 has a double gate structure, it may have a single gate structure or a multi-gate structure provided with a plurality of gate electrodes.

Next, ZnO is formed to a thickness of 100 nm by a sputtering method as the pixel translucent electrode 670, and is etched to form a predetermined electrode. In this embodiment, since no sensor is provided on the active matrix substrate, there is no need to provide a sensor window, and the pixel electrode is constituted by a reflective electrode and a translucent electrode. A pixel electrode pattern was designed so that a sensor could be arranged corresponding to each pixel as a two-dimensional arrangement when the display panel was laminated with a counter substrate later.

As the substrate on the opposite side, glass of the same material as the substrate on the active matrix side is used. A sensor unit is formed on this substrate by a manufacturing method similar to that of the first embodiment in a previously designed arrangement. The circuit for driving this sensor may be formed on the same substrate as the sensor by applying the above-described manufacturing process of the polycrystalline silicon TFT. Alternatively, only the matrix wiring and the sensor element are formed, and the driving circuit is an external IC. However, considering only the portability, which is one of the objects of the present invention, it is easier to realize a smaller volume when the drive circuit is also formed on the substrate. In this embodiment, the drive circuit and the sensor are provided on the same substrate. (FIG. 11B 503)

On the other surface of the substrate, a color filter 502 made of an acrylic resin is formed in RGB at a previously designed place using a known technique. This color filter can be provided on the sensor unit 503.

The counter substrate 50 thus formed is
0 and the active matrix substrate 601,
An image recognition device-integrated display device as shown in FIG. Compared to the first embodiment, the second embodiment is advantageous in that an error in reading information (so-called blur) is small because the distance between the document and the sensor unit is short. Further, a sheet 512 for adding an optical effect can be provided between the polarizing plate 511 and the counter substrate, and more light can be used than when an optical fiber plate is provided as this sheet.
When a lens array sheet is provided, light from a document can be imaged on the sensor, and reading errors can be further reduced.

In this embodiment, the color filter and the sensor section are provided on the opposite substrate. However, in the case of a so-called monochrome display, the color filter is not required. However, the provision of the sensor at a position closer to the document is the same as in this embodiment. Has a similar effect.

In particular, the display device can be selectively used in the reflection mode and the transmission mode depending on the place where it is to be used, so that the power consumption is suppressed and the image passing through the translucent electrode of the pixel electrode at the time of image recognition. An original can be read by light from the backlight 501. As a result, a PDA (portable personal terminal) incorporating an image recognition device-integrated display device can be suppressed to a very small volume, and a function of reading information such as a business card, a photograph or a digital camera can be realized. .

Embodiment 3 This embodiment is realized by using the active matrix substrate shown in FIG. 12 as the substrate of the device of the present invention shown in FIG. 11A.
The positional relationship between the sensor element and the active element for switching with respect to the substrate is reversed from that of the first embodiment. This T
The FT element employs a TOP gate structure.

In the first embodiment, the light shielding layers 405 and 406 are formed below the TFT element as necessary. In the present embodiment, the sensor element itself also serves as the light shielding layer. As a result, the process can be shortened,
It was possible to prevent a malfunction (crosstalk) of the TFT element due to a backlight necessary for display in the transmission mode.

In this embodiment, the entire sensor element is extended so as to be a light-shielding layer of the TFT element. However, at least a part of the sensor element is extended so long as it has a function of suppressing crosstalk of the TFT element. The same effect can be obtained.

A semiconductor device applicable to this embodiment can be manufactured according to the steps described in the first or second embodiment.

(Example 4)

This embodiment is realized by using the active matrix substrate shown in FIG. 13 as a substrate of the image recognition device-integrated display device of the present invention shown in FIG. 11A. Bottom-gate type TFT having a sensor element and a switching active element structure different from the first embodiment.
You are using

In the first embodiment, the light-shielding layers 405 and 406 are formed below the TFT element as necessary. In the present embodiment, the gate electrode 808 of the TFT element itself has the structure also serving as the light-shielding layer. I have. As a result, the step of providing a special light-shielding layer can be shortened, and a malfunction (crosstalk) of the TFT element caused by backlight required for display in the transmission mode can be prevented.

(Example 5)

This embodiment will be described with reference to FIG. FIG. 14 shows an example of a circuit configuration that can be applied to the image recognition device-integrated display device of the present invention. For convenience of explanation, FIG. 14 shows a circuit configuration of a semiconductor device having 2 × 2 (vertical × horizontal) pixels, but many pixels are actually formed on an actual substrate. For example, in the case of a display device of the VGA standard, the number of pixels is 640 × 480, and the SVGA
That of the standard is 800 × 600. The peripheral drive circuit is
Briefly shown in blocks.

101 is a pixel TFT, 102 is a liquid crystal, 10
3 is an auxiliary capacitor, 104 is a sensor TFT, 105 is a photodiode PD, 106 is an auxiliary capacitor, 107 is a signal amplification TFT, 108 is a reset TFT, 109 and 11
0 is an analog switch. Reference numeral 120 denotes a bias TFT, 121 denotes a transfer TFT, 122 denotes a sample and hold capacitor, 123 denotes a discharge TFT, 124 denotes a final buffer amplification TFT, and 125 denotes a final buffer bias TFT. The circuit constituted by these 101 to 108 is called a matrix circuit. Also, 101 and 103 are pixel units A, and 104, 105, 106, 107 and 108 are sensor units B. 111 is a sensor output signal line, and 112 is an image input signal line. 114 is a fixed potential line. 115 is a pixel source signal line side driving circuit, 116 is a pixel gate signal line side driving circuit, 11
7, a sensor horizontal drive circuit; and 118, a sensor vertical drive circuit.

The image recognition device-integrated display device of the present invention
When displaying an image, an image signal (gradation voltage) input from an image input signal line is supplied to a pixel TFT by a pixel source signal line side driving circuit 115 and a pixel gate signal line side driving circuit 116, The liquid crystal sandwiched between the pixel electrode connected to the TFT and the counter electrode can be driven to display an image.

FIG. 14 is different from FIG. 1 in that the storage capacitor 103 provided in each pixel and the storage capacitor 106 provided in the sensor are connected to the same fixed potential line 114. is there. That is, in the cross-sectional view shown in FIG. 5, the upper transparent electrode 422 of the sensor overlaps the reflective electrode 425 or the pixel translucent electrode 424 of the pixel, and the interlayer insulating film 423 provided therebetween. Since is a dielectric, a capacitor can be positively realized in this portion. This can be the auxiliary capacitors 103 and 106 shown in FIG.

With this configuration, the area of the capacitor in the substrate can be reduced to half. That is, the auxiliary capacitance 103 required for display and the auxiliary capacitance 106 required for image reading are not used at the same time after all, so they can be shared as in this embodiment. Thereby, effective use of the substrate and shortening of the manufacturing process can be realized.

In FIG. 14, pixel source signal line side drive circuit 115 and pixel gate signal line side drive circuit 116
Shows an analog drive circuit that handles analog image signals, but is not limited to this. That is, a digital drive circuit equipped with a D / A conversion circuit that handles digital video signals may be used.

Further, in the display device integrated with an image recognition device of the present invention, the incident external image information (optical signal) is read by the photodiode PD105, which is a photoelectric conversion element, and is converted into an electric signal. An image is captured by the sensor vertical drive circuit 118. This video signal is taken into another peripheral circuit (memory, CPU, etc.) from the sensor output signal line 111. Further, not only the auxiliary capacitance but also a display driving circuit and an image recognition driving circuit can be shared.

The method of manufacturing the semiconductor device according to the present embodiment can be easily realized with reference to the first embodiment.

[0129]

【The invention's effect】

The manufacturing process of the semiconductor device of the present invention is the same as that of the conventional display device, except for the addition of a photoelectric conversion element manufacturing step. Therefore, since a conventional manufacturing process can be used, it can be manufactured easily and at low cost. In addition, the semiconductor device manufactured according to the present invention does not change the shape and size of the substrate from the conventional panel even when the semiconductor device is provided with the sensor function. Therefore, size and weight can be reduced.

The light receiving area of the sensor cell is substantially the same as the pixel area of the display cell, and is larger than that of the single crystal CCD. Therefore, the sensor of the present invention can have high sensitivity. Furthermore, the power consumed by the image sensor of the semiconductor device of the present invention can be reduced as compared with the CCD structure.

Since the configuration of the display device can realize the reflection mode and the transmission mode, the power consumption of the entire device can be suppressed. Particularly, in the case of a portable terminal, the volume can be easily reduced. Features.

In particular, the display device can be selectively used in the reflection mode and the transmission mode depending on the place where it is to be used, so that the power consumption is suppressed and the image passing through the translucent electrode of the pixel electrode at the time of image recognition. An original can be read by light from the backlight 501. As a result, a PDA (portable personal terminal) incorporating an image recognition device-integrated display device can be suppressed to a very small volume, and a function of reading information such as a business card, a photograph or a digital camera can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of an image recognition device-integrated display device of the present invention.

FIG. 2 is an exploded view of the image recognition device-integrated display device of the present invention.

FIG. 3 is an exploded view of the image recognition device-integrated display device of the present invention.

FIG. 4 is a schematic layout diagram in the vicinity of a pixel of the image recognition device-integrated display device of the present invention.

FIG. 5 is a cross-sectional view of an active matrix substrate of an embodiment of the image recognition device-integrated display device of the present invention.

FIG. 6 is a diagram showing a method for manufacturing an image recognition device-integrated display device of the present invention.

FIG. 7 is a view illustrating a method for manufacturing an image recognition device-integrated display device of the present invention.

FIG. 8 is a diagram showing a method for manufacturing an image recognition device-integrated display device of the present invention.

FIG. 9 is a diagram illustrating a method for manufacturing an image recognition device-integrated display device of the present invention.

FIG. 10 is a diagram showing a method for manufacturing an image recognition device-integrated display device of the present invention.

FIG. 11 is a cross-sectional view illustrating a schematic configuration of an image recognition device-integrated display device of the present invention.

FIG. 12 is a cross-sectional view of an active matrix substrate according to an embodiment of the image recognition device-integrated display device of the present invention.

FIG. 13 is a cross-sectional view of an active matrix substrate according to an embodiment of the image recognition device-integrated display device of the present invention.

FIG. 14 is a circuit diagram of an embodiment of an image recognition device-integrated display device of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 27/146 G02F 1/136 500 29/786 H01L 27/14 C 21/336 29/78 612Z H04N 5 / 335

Claims (8)

[Claims] A plurality of pixel portions having active elements and arranged in a matrix; an active matrix substrate using a reflective material and a translucent material as electrodes of the pixel portions; A plurality of sensor units arranged in a matrix, the sensor unit has a photoelectric conversion element, when reading an external image, the translucent material An image-recognition-device-integrated display device that can read information using light that has passed through. 2. The display device integrated with an image recognition device according to claim 1, wherein the active element is constituted by a bottom gate type TFT. 3. A display panel comprising a plurality of pixel portions having active elements and arranged in a matrix, an active matrix substrate using a reflective material and a translucent material as electrodes of the pixel portions, and a display panel. A plurality of sensor units arranged in a matrix on a counter substrate, wherein the sensor unit has a photoelectric conversion element, and when reading an external image, An image-recognition-device-integrated display device capable of reading information using light passing through a conductive material. 4. A display device integrated with an image recognition device according to claim 3, wherein a color filter is provided on the counter substrate. 5. An active matrix substrate having a plurality of pixel portions having active elements and arranged in a matrix, an active matrix substrate using a reflective material and a translucent material as electrodes of the pixel portion, and A plurality of sensor units arranged in a matrix, wherein the sensor unit has a photoelectric conversion element, and at least a part of the photoelectric conversion element overlaps with the active element. The image recognition device integrated display device is extended as follows. 6. A display device integrated with an image recognition device, wherein the active element according to claim 5 comprises a top gate type TFT. 7. A display device comprising: an active matrix substrate having active elements and having a plurality of pixel units arranged in a matrix; and a plurality of sensor units arranged in a matrix on the active matrix substrate. The image recognition device-integrated display device, wherein a pixel capacitance portion provided in the pixel also serves as an image recognition capacitance portion provided in the sensor portion. 8. A display device integrated with an image recognition device, wherein a reflective material and a translucent material are used as the electrodes of the pixel portion according to claim 7.