JPH1175101A - Electrooptic device and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption in the configuration of the device in a way that an image sensed by an active matrix type image sensor is displayed on a liquid crystal display device. SOLUTION: In the case the device has an active matrix image sensor employing a MOS image pickup element, one pixel 101 is divided into two. One unit pixel group RGB outputs a forward signal and the other unit pixel group outputs an inverted signal. Thus, in the case of driving directly the liquid crystal display device by an output from the image sensor, the inversion is simply realized. Since the symmetry between the forward signal and the inverting signal is especially improved, this device is advantageous in the case of processing a moving image. Thus, the simple configuration and operation is realized to materialize low power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD [0001] The invention disclosed in the present specification is:
The present invention relates to a configuration including an active matrix type image sensor and an active matrix type display. Specifically, the present invention relates to a configuration having a function of displaying an image captured by an active matrix type image sensor on a liquid crystal display in real time.

The active matrix type means that each pixel arranged in a matrix has a TF
It is defined as a structure in which active elements represented by T are arranged.

[0003]

2. Description of the Related Art With the advent of the multimedia age, information terminal equipment capable of handling image information is required.

[0004] As a device for handling image information, a configuration called a digital camera is also known. This configuration has a function of storing a still image in a memory or a magnetic disk, and a function of digitally processing an image.

[0005] In a device that handles such image information, it is necessary to include an image receiving unit for capturing the image information and a display unit for displaying the captured image.

Generally, as means for taking in image information, C
A CD camera is used. An LCD panel is used as a means for displaying image information.

An image signal captured by a CCD camera cannot be directly input to a liquid crystal display as it is.

This is because the output from the CCD is a time-series signal that is not separated into RGB, but the liquid crystal display requires each of the RGB signals individually.

Further, in a liquid crystal display, it is necessary to reverse the polarity of the applied voltage at a predetermined timing in order to prevent the deterioration of the liquid crystal, but the output format from the CCD is not so. At this point, the image signal captured by the CCD camera cannot be directly input to the liquid crystal display as it is.

Therefore, as a general configuration, an output from a CCD camera is converted into a digital signal by an A / D conversion circuit, and various digital processes are performed on the output.
A configuration is employed in which an A-conversion circuit generates an analog signal for driving a liquid crystal display.

By performing digital processing, various corrections and processing (processing such as zooming and color correction) of an image can be easily realized. However, this requires a complicated circuit.

[0012]

A portable information processing terminal is desired to be able to operate on a battery because it is portable. Naturally, low power consumption is desired.

For example, in a digital camera, if the operation time is only several tens of minutes, the practicality is reduced. The same applies to a video camera and a portable information processing terminal.

Power is mainly consumed by the CCD camera unit, the liquid crystal display unit, and the image processing circuit unit.

In order to reduce the power consumption of the liquid crystal display, a reflection type panel may be used. Most of the power consumption of the liquid crystal display is consumed by the backlight. Therefore, by using the reflection type, the power consumption can be significantly reduced.

On the other hand, the CCD camera consumes a relatively large amount of power because it requires a plurality of power supply voltages and a relatively high voltage.

Further, an image processing circuit for processing a digital signal also consumes a large amount of power. The image processing circuit has a CCD
In order to convert a signal output from a camera into a signal that can be input to a liquid crystal display, a function of separating and rearranging color signals (changing timing) is required.
When such an operation is performed, a large amount of power is consumed.

In a CCD camera or an image processing circuit,
Efforts have been made to develop circuits that reduce power consumption. However, it is difficult to greatly reduce power consumption in circuits that process video signals having a wide signal band.

Although the image processing circuit is formed as an IC, it occupies a relatively large area, which is an obstacle to making the overall configuration compact.

In the image processing circuit, since heat is generated considerably, it is necessary to take measures against the heat.

[0021] It is an object of the invention disclosed in this specification to provide a configuration having an image receiving unit and a display unit in which power consumption is reduced as much as possible. Another object is to simplify the configuration as much as possible.

[0022]

The invention disclosed in the present specification employs a configuration in which a liquid crystal display can be directly driven by a signal output from an image sensor as an image receiving unit.

That is, a signal (analog signal) from the image sensor is directly input to a liquid crystal display without being digitally processed.

By doing so, a complicated signal processing circuit is omitted, the configuration is simplified, and low power consumption is achieved.

Therefore, in the invention disclosed in this specification, a pixel arrangement in consideration of the inversion driving of the liquid crystal display is adopted in the active matrix type image sensor.

More specifically, the configuration is such that the pixels on the image sensor side are separated into those for forward output and those for inversion output, corresponding to one pixel of the liquid crystal display.

That is, two pixels, one for forward output and one for inverted output, are arranged in the image sensor corresponding to one pixel of the liquid crystal display.

In this configuration, the output from the image sensor for writing information to one pixel of the liquid crystal display is from two pixels, one for forward output and the other for inversion output. Outputs from the two pixels are converted into signals having polarities inverted from each other, and display of one pixel is represented by two timings.

Here, assuming that the two pixels of the image sensor are arranged adjacent to each other, by setting the timing appropriately, the outputs of the two become almost the same. That is, almost the same signal waveform is obtained for the forward output and the inverted output. (This is defined as a similar waveform in this specification)

In this case, since the symmetry of the signal between the forward output and the inverted output can be made extremely high, the operation can be made ideal when the liquid crystal display is driven in the frame inversion mode or the scanning line inversion mode. This is effective when a high-speed moving image is received by the image sensor and displayed.

One of the inventions disclosed in the present specification has an active matrix type image sensor and an active matrix type liquid crystal display, and the image corresponding to one unit pixel of the liquid crystal display. The sensor is provided with two unit pixels, and the two unit pixels are arranged adjacent to each other. At a predetermined timing, one unit pixel of the liquid crystal display includes image information from the two unit pixels of the image sensor. Is written continuously, and one of the outputs from the two unit pixels is input to the liquid crystal display with its polarity inverted with respect to the other output.

In the above configuration, one unit pixel of the arbitrarily selected liquid crystal display and two unit pixels of the image sensor corresponding to the unit pixel have a corresponding relationship in their respective active matrix circuits. As in

One unit pixel of the liquid crystal display arbitrarily selected and two unit pixels of the image sensor corresponding to the unit pixel are captured by the image sensor and further displayed on the liquid crystal display. Correspond to the same part of

In this case, signal waveforms including image information from two unit pixels arranged adjacent to each other are similar to each other.

For example, in an active matrix type image sensor as shown in FIG. 1, an image read by an odd-numbered row of pixels and an image read by an even-numbered row of pixels are similar.

According to another aspect of the present invention, there is provided an active matrix type image sensor having 2N unit pixels and an active matrix type liquid crystal display having N unit pixels. The signals output from the N unit pixels are input to the liquid crystal display via a circuit that inverts the polarity of the signals output from the other unit pixels. is there.

According to another aspect of the invention, an active matrix type image sensor having 2N unit pixels and an active matrix type liquid crystal display having N unit pixels are provided. The number of unit pixels for forward output and the number N of unit pixels for inverted output are arranged, and the unit pixel for forward output and the unit pixel for inverted output are arranged adjacent to each other. Features.

Further, in the above configuration, a unit pixel for forward output and two unit pixels for inversion output are arranged as a set in the image sensor corresponding to any one pixel of the liquid crystal display. The image information output from the two unit pixels is continuously written into any one pixel of the liquid crystal display at an arbitrary timing.
Signals containing image information from two unit pixels are similar,
And the polarities are opposite.

According to another aspect of the invention, there is provided a method for displaying an image captured by an active matrix type image sensor on an active matrix type liquid crystal display, wherein the image sensor corresponds to one unit pixel of the liquid crystal display. Thus, two unit pixels are arranged, and in any one unit pixel of the liquid crystal display,
(1) a step of writing predetermined image information at a predetermined timing; and (2) writing image information similar to the image information after holding the image information written in the step (1) for a predetermined period. And a step,
The two signals including the image information in the steps (1) and (2) have an opposite polarity to each other.

In this operation, the image sensor 2
The two unit pixels are arranged adjacent to each other, and the (1)
The two signals including the image information in the steps (2) and (3) have similar waveforms.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an example in which a liquid crystal display is operated in a row inversion mode will be described.

FIG. 1 shows a schematic configuration of an active matrix type image sensor having 2 × 3 pixels.

FIG. 1 shows a configuration of 2 × 3 pixels including six pixels (one of which is indicated by 101) constituted by six unit pixels.

For example, the pixel 101 has six unit pixels (R
₃₁₁ , G ₃₁₁ , B ₃₁₁ , R ₃₁₂ , G ₃₁₂ , B ₃₁₂ ).

In the figure, to simplify the description, 2
Although only three pixels are described, the configuration is actually provided with the required number of pixels.

Here, a matrix of m rows and n columns is considered. (Rows extend horizontally, columns extend vertically)

In this case, the unit pixel is generally indicated by R _mnp . Here, (m, n) indicates the address of the pixel.
A set of unit pixels having the same (m, n) forms a pixel. P is a code corresponding to the forward output and the inverted output.

For example, if the output of the pixel at p = 1 is input to the liquid crystal display as a forward output, the output of the pixel at p = 2 is input to the liquid crystal display as the inverted polarity (as an inverted output). Is done. The selection of the polarity of the signal is arbitrary, and if one is defined as a forward output, the other is an inverted output.

RGB is Red, Blue, Gre.
2 shows each dye of en. Here, the structure is based on the assumption that a color image is handled. If a monochrome image is handled, a set of RGB may be considered as one unit pixel.

The feature of the image sensor shown in FIG. 1 _lies in that, in each unit pixel indicated by R _mnp , two unit pixels for forward output and inverted output identified by p exist.

That is, one pixel includes a unit pixel group for forward output indicated by p = 1 and a unit pixel group for inverted output indicated by p = 2.

The unit pixels for the forward output and the inverted output are arranged adjacent to each other. This is because two unit pixels capture similar image information.

Here, the similarity means that when they are completely the same,
Or when it can be regarded as the same.

For example, an image captured by a unit pixel group of p = 1 at a certain point in time is spatially shifted by one unit pixel from an image captured by a unit pixel group of p = 2.
The timing of storing the image information is shifted by one hundredth of one frame (indicated by 1 / 2t _row ). In this case, the two images can be considered almost identical.

In such a case, it can be said that the image information of the image captured by the unit pixel group of p = 1 and the image information of the image captured by the unit pixel group of p = 2 are similar.

In such a case, the waveforms of signals including two pieces of image information (outputs from the image sensor) are similar.
Therefore, by inverting the polarity, an ideal inverted signal can be generated.

In the configuration shown in FIG. 1, each unit pixel is
It has an optical sensor structure with at least one MOS transistor. This structure is generally called a MOS type solid-state imaging device.

As the simplest example of a unit pixel structure employing a MOS type image pickup device, one photodiode and
And a structure including one switching MOS transistor.

In the technical field of image sensors, this structure is generally called a passive type. But,
Here, a structure having an active element in each pixel is defined as an active type.

As another example of a unit pixel structure employing a MOS type image pickup device, there has been known a form in which charges accumulated in a photodiode are detected as potential changes and amplified.

In this structure, each pixel needs at least three MOS transistors for detection, reset, and amplification.

FIG. 2 shows a schematic configuration of a liquid crystal display to be paired with the image sensor shown in FIG.

In the configuration shown in FIG. 2, the pixel denoted by 201 is composed of three unit pixels corresponding to RGB (one of them is denoted by 202).

The address of each unit pixel is indicated by _Rmn .
The address indicated by (m, n) corresponds to the arrangement of the unit pixels of the image sensor.

In the figure, to simplify the description, 2
Although only three pixels are described, the configuration is actually provided with the required number of pixels.

The liquid crystal display shown in FIG. 2 is called an active matrix type. Each unit pixel has at least one switching MOS thin film transistor.

As is clear from FIGS. 1 and 2, one pixel of the image sensor has twice as many unit pixels as one pixel of the liquid crystal display.

This is because two unit pixels, one for forward output and one for inverted output, are arranged in the image sensor corresponding to one unit pixel of the liquid crystal display.

Then, one unit pixel of the liquid crystal display and two unit pixels of the image sensor provided corresponding thereto are arranged at the same address in each other's active matrix circuit.

The image sensor shown in FIG. 1 and the liquid crystal display shown in FIG. 2 are connected via the conversion circuit shown in FIG.

The RGB outputs of the image sensor shown in FIG. 1 are respectively input to the RGB circuits of the conversion circuit shown in FIG.

The RGB outputs of the conversion circuit of FIG. 3 are connected to the RGB input portions of the liquid crystal display shown in FIG.

An example of the operation when the image captured by the image sensor of FIG. 1 is displayed on the liquid crystal display of FIG. 2 will be described below. Here, an example in which a liquid crystal display mode called row inversion is used will be described.

Here, the concept of one frame is changed from the pixel at the address (1,1) (unit pixel group indicated by (R ₁₁ , G ₁₁ , B ₁₁ )) of the liquid crystal display to the pixel at the address (m, n) It is defined as the time required to write image information to the bottom right pixel of the screen).

Accordingly, one screen is displayed in one frame time. Generally, an operation of 30 fields or 60 fields is performed per second, and an image is displayed.

FIG. 4A shows the information reading timing of the image sensor in a certain frame.

The period indicated by t _row is the time for writing image information to one row of the liquid crystal display. Also, t _A
Is a period during which image information is accumulated in the optical sensor of the image sensor. Note that t _A coincides with the time of one frame.

First, in the first one frame, image information is read out sequentially from the first row of the image sensor. This operation is performed according to the operation of the vertical shift register.

The operation of one predetermined row in the image sensor is performed in half the time t _{row in} which image information is written to one predetermined row of the liquid crystal display. Therefore, the sum of the read time of the image information in the two rows of the image sensor corresponds to the time of writing the image information to one row of the liquid crystal display.

In a time (1 / 2t _row ) for reading image information from one row of the image sensor, the image information is sequentially read from a unit pixel group constituting the row according to the operation of the horizontal shift register.

[0081] In this case, the time required to read the information from one unit pixel is t _s.

Here, the operation at a predetermined time is considered.
First, image information is read from the first line of the image sensor. Reading of the image information in accordance with operation of the horizontal shift register shown in FIG. 1, in the period of 1 / 2t _row,
It is performed sequentially.

This output passes through the conversion circuit shown in FIG.
It is input to the liquid crystal display shown in FIG. Then, the image information is written on the first line of the liquid crystal display.

At this point, the changeover switch is set to "1".
It has become. That is, in the first 1/2 t _row period, the changeover switch is "1".

The image information written in the unit pixel of the liquid crystal display is held in the unit pixel for a period of about 1/2 t _row .

Next, the image information in the second row of the image sensor is read out according to the operation of the vertical shift register having the configuration shown in FIG. 1, and the image information is sequentially written again in the first row of the liquid crystal display.

At this time, as shown in FIG. 4B, the polarity switch is switched to “2”. That is, in the next 1/2 t _row period, the changeover switch is set to “2”.
It has become.

The image information of the first and second rows of the image sensor is spatially shifted by one pixel and temporally by 1/2 t _row . However, this shift is slight, and the two pieces of image information can be regarded as substantially the same.

Therefore, t is displayed on the first line of the liquid crystal display.
_The image information written at the time of _row is written by being divided into two parts in time, and the image information similar (substantially the same) to the image information written during the first ｔ t _row period is obtained. The next one again with the signal polarity reversed
It is written in the period of / 2t _row .

The two pieces of image information are obtained from the pixel group on the first row and the pixel information on the second row, respectively, of the image sensor.

Thus, the image information on the third and fourth lines of the image sensor is written on the second line of the liquid crystal display, and the image information on the fifth and sixth lines of the image sensor is written on the liquid crystal display. The operation of writing in the third row is sequentially performed, and one frame is completed.

The RGB signals are independently output from the image sensor. The RGB signals are input to the liquid crystal display at a parallel timing to form a color image.

The operation of the image sensor and the operation of the liquid crystal display are synchronized with each other. However, since the signal processing time is generally delayed, the operation is shifted by that amount. However, this shift is not perceived by humans, and a configuration in which an image captured by an image sensor is substantially displayed in real time can be realized.

In this configuration, for one pixel of the liquid crystal display, two pixels for the forward signal and the inverted signal are prepared on the image sensor side, so that the inversion operation can be realized with a simple configuration. it can.

Further, since signals having substantially the same waveform and opposite polarities are successively input to one pixel of the liquid crystal display, an operation in which deterioration of liquid crystal and image is suppressed as much as possible can be performed. .

[0096] Since the configuration and operation are simplified, power consumption can be greatly reduced as compared with the case where a conventional digital processing circuit is used.

[0097]

Embodiment 1 In this embodiment, an example of an apparatus provided with an image sensor as shown in FIG. 1 and a liquid crystal display as shown in FIG. 2 will be described.

Here, an example of a digital still camera is shown. FIG. 5 shows a schematic configuration thereof. FIG. 6 is a schematic equivalent block diagram.

FIGS. 5A and 5B show the case where the viewing angles are changed by 180 degrees.

The configuration shown in FIG. 5 includes a light receiving section 1102 having an active matrix type image sensor arranged on a main body 1101, a display section comprising an active matrix type liquid crystal display arranged on the back side thereof, and an operation switch 1105; Shutter 1104, strobe 1103
It has.

Here, the image sensor may be one in which a MOS type image pickup device composed of a TFT is disposed in each pixel, or one in which a MOS type image pickup device using a single crystal wafer is disposed in each pixel.

The liquid crystal display has a configuration in which a TFT is arranged in each pixel, and a peripheral driving circuit is also integrated on the same substrate (glass substrate or quartz substrate).

The image captured by the image sensor of the light receiving unit 1102 is converted into a signal for driving the liquid crystal display by a conversion circuit as shown in FIG. 3, and is displayed on the liquid crystal display in real time. In this state, 30 in FIG.
The portion indicated by 2 operates.

Then, the shutter 1104 is pressed according to the user's judgment, and at that timing, a still image is taken into the digital processing circuit and digitally processed. And
Further, the image information is taken into the memory.

At the moment when the shutter 1104 is pressed, the circuit indicated by 301 operates. Until then, the circuit 301
Is in a standby state.

Thus, it is possible to make the digital processing circuit consuming a large amount of power unnecessary to always operate.

As a whole, the time during which the shutter is pressed is a short time. Therefore, low power consumption can be achieved by using a configuration in which the circuit denoted by 301 operates only for that time or a time required for it.

The circuit structure shown in this embodiment can be constituted by a TFT (thin film transistor) formed on a glass substrate or a quartz substrate. This is primarily due to the simplicity of the circuit. Another major factor is that digital signal processing that requires high-speed operation of transistors is not required.

Note that the circuit configuration shown in this embodiment can naturally be configured using a normal IC. Even in this case, the configuration can be simplified as a whole, and further lower power consumption can be obtained.

[Embodiment 2] This embodiment shows a configuration in which an image sensor as shown in FIG. 1 and a liquid crystal display as shown in FIG. 2 are integrated on the same substrate.

In the present embodiment, an example of a portable information processing terminal as shown in FIG. 7 will be described.

In the configuration shown in FIG.
, A display unit 1002 including an active matrix type liquid crystal display device, a light receiving unit 1003 including an active matrix type image sensor, a microphone 1004, and a speaker 1.
005.

Information is input by inputting audio information from the microphone 1004 and image information from the light receiving unit 1003. Further, input of character information and various operations can be performed directly from the input pen 1006 via a touch sensor provided in the display portion 1002.

The image captured by the light receiving unit 1003 is displayed on the display unit 10.
02 can be displayed in real time in practical use.

In the configuration shown in this embodiment, the active matrix circuit of the active matrix type liquid crystal display device provided in the display section is the same as the active matrix circuit of the active matrix type image sensor provided in the light receiving section. It is assumed that they are integrated on a substrate.

[Embodiment 3] This embodiment shows a structure in which an image sensor and a liquid crystal display are integrated on the same substrate.

FIG. 8 shows an outline of the configuration. FIG. 8 illustrates an active matrix type liquid crystal display device and an active matrix type image sensor integrated on the same substrate.

In the configuration shown in FIG.
Are a pair of glass substrates. A liquid crystal 405 is held between the pair of glass substrates.

The liquid crystal 405 is sealed by a sealing material 408. Note that the sealant 408 also has a function of holding the pair of glass substrates 401 and 402 at regular intervals.

In the configuration shown in FIG. 8, polarizing plates 403 and 407, an active matrix circuit 406, a liquid crystal 405, and a counter electrode 404 are arranged in the liquid crystal display portion.

In the image sensor section, an active matrix type image sensor circuit 409 is arranged. 410 is not filled with liquid crystal and exists as a simple gap.

Reference numeral 411 denotes a pedestal for supporting the lens 412. Reference numeral 413 denotes a filter (IR filter) for shielding infrared light.

In the configuration shown in FIG. 8, an active matrix circuit 406 of a liquid crystal display portion and an active matrix circuit 409 of an image sensor portion are integrated on one glass substrate 401 by TFTs.

The electrical connection between the two active matrix circuits is made via a conversion circuit as shown in FIG.

Although not shown in FIG. 8, the conversion circuit composed of the operational amplifier as shown in FIG. 3 is also constituted by the TFT formed on the glass substrate 401.

FIG. 9 shows a detailed manufacturing process of the structure shown in FIG. Here, an example is shown in which a TFT provided in an image sensor portion and a TFT provided in a liquid crystal display portion are simultaneously manufactured on a glass substrate.

First, an amorphous silicon film (not shown) is formed on a glass substrate 501 to a thickness of 50 nm by low pressure thermal CVD.

Here, an example in which an amorphous silicon film is formed directly on a glass substrate will be described. However, a silicon oxide film, a silicon oxynitride film, or the like is formed on a glass substrate as a base film, and A configuration may be adopted in which an amorphous silicon film is formed first.

Next, by irradiating a laser beam,
The amorphous silicon film (not shown) is crystallized.

As a crystallization technique, a method using heat treatment or irradiation with strong light may be employed.

After a crystalline silicon film (not shown) is obtained, the film is patterned to obtain patterns indicated by 502 and 503 in FIG.

Next, as shown in FIG. 9B, a silicon oxide film 504 functioning as a gate insulating film is formed to a thickness of 100 nm by a plasma CVD method.

Further, an N-type microcrystalline silicon film whose resistance has been lowered by heavy doping is formed by a low pressure thermal CVD method, and is patterned to form a gate electrode 505.
And 506 are formed.

As a material for the gate electrode, various silicide materials, metal materials, and the like can be used. Alternatively, a stacked structure of a metal material and a silicon material can be used.

Next, phosphorus is doped by the plasma doping method using the gate electrodes 505 and 506 as a mask.

Here, an example in which an N-channel TFT is manufactured is shown, and an example in which phosphorus is doped is shown. However, in the case of manufacturing a P-channel TFT, boron is doped.

In the case of manufacturing an N-channel TFT and a P-channel TFT, two conductive TFTs are separately formed by performing selective doping.

Here, 507, 509, 510, 51
The region 2 is doped with phosphorus. Also, 508,
The region 511 is not doped.

Here, in the TFT of the image sensor portion, 507 is a source region, 509 is a drain region, and 509 is a drain region.
8 is a channel region.

In the TFT of the liquid crystal display, 51
0 is a source region, 517 is a drain region, and 511 is a channel region.

Thus, the state shown in FIG. 9B is obtained. Next, a silicon oxide film 513 is formed as an interlayer insulating film by plasma CVD.
The film is formed to a thickness of 300 nm by the method.

Next, a contact hole is formed. A source electrode 514 and a drain electrode 515 of the TFT in the image sensor portion are formed. Further, a source electrode 516 and a drain electrode 517 of the TFT of the liquid crystal display portion are formed.
(FIG. 9 (C))

The above-mentioned source electrode and drain electrode are formed of a laminated film of a titanium film, an aluminum film and a titanium film formed by a sputtering method.

Next, an acrylic resin film 518 is formed by spin coating. Conditions are set so that the surface of the acrylic resin film becomes flat. The film thickness is set to be 600 nm at the minimum part.

Next, a contact hole is formed, and an electrode 519 and a BM (black matrix) are formed using a titanium film.
520 is formed. (FIG. 9 (C))

This titanium film (not shown) becomes one electrode of the photoelectric conversion layer in the image sensor portion. In the liquid crystal display unit, a BM is formed.

Next, an acrylic resin film (not shown) is formed.
Further, by patterning this resin film, 52
An acrylic resin film 2 is formed.

Next, an amorphous silicon film 521 is formed by forming an amorphous silicon film by a plasma CVD method and patterning this film. This amorphous silicon film 521 functions as a photoelectric conversion layer.

Next, a contact hole is formed in the acrylic resin film 522, and an ITO electrode 524 is formed as a pixel electrode. At the same time, an ITO electrode 523 is formed.

In this configuration, the output (drain) of the TFT in the image sensor portion is connected to a photoelectric conversion device (optical sensor) including one electrode 519, a photoelectric conversion layer 521, and the other electrode 523. I have.

In the liquid crystal display, a pixel electrode 524 is connected to the output (drain) of the TFT.

Thus, the image sensor section and the liquid crystal display section can be constituted by the TFTs simultaneously formed on the same substrate in the same steps.

Here, the TFTs arranged in the pixel portions of the image sensor section having the active matrix type and the liquid crystal display section have been described. Actually, peripheral driving circuits, conversion circuits, and the like are further integrated on the same substrate.

As is clear from FIG. 9, in this embodiment, the image sensor section and the liquid crystal display section can be integrated on the same substrate. Such a configuration is useful for a configuration aiming at simplification of the structure and reduction in production cost.

The structure of the TFT may be a top gate type in which a gate electrode is provided on the active layer as shown in this embodiment, or a bottom gate in which the gate electrode is provided between the active layer and the substrate. It may be a type. Further, the top gate type and the bottom gate type may be separately formed on the same substrate.

[Embodiment 4] Generally, the output of an image sensor is not linear with respect to the incidence of an optical signal constituting an image. Alternatively, it has a non-linear area.

Therefore, generally, (1) a region where the output can be regarded as linear with respect to the input is used. (2) Correct the non-linear region of the output of the image sensor and perform an electrical process so that the final output becomes linear. Such a configuration is adopted.

In general, the above-described configuration is applied to digital signals. However, handling digital signals complicates the circuit configuration and increases power consumption.

In this embodiment, the amplification factor of the operational amplifier circuit of the conversion circuit shown in FIG. 3 is changed according to the intensity of the input signal.

That is, the final output is made linear by setting the amplification factor to have a nonlinearity opposite to the nonlinearity of the output of the image sensor.

Such a configuration can be realized by devising a feedback circuit of the operational amplifier circuit.

[0162]

By utilizing the invention disclosed in this specification, it is possible to provide a configuration having an image receiving unit and a display unit, in which power consumption is reduced as much as possible.

In the present specification, the image signal supplied to one pixel of the liquid crystal display corresponds to the forward signal and the inverted signal of the image signal.
Two pixels are prepared on the image sensor side, a forward signal and an inverted signal are generated for each of the two pixels, and the signals are supplied to one pixel of the liquid crystal display at two timings.

Thus, an ideal liquid crystal display can be driven by a simple circuit that does not follow digital processing.

In particular, in this configuration, since no digital signal processing is performed, low power consumption can be realized.

[0166] While having a simpler configuration,
In an operation of displaying an image captured by an image sensor on a liquid crystal display, an inversion operation for preventing deterioration of liquid crystal can be performed in a state close to ideal.

Further, since the circuit configuration is simple and the power consumption is small, it is possible to make the configuration advantageous for the problem of heat generation.

The invention disclosed in this specification is particularly effective when a high-speed moving image is captured by an image sensor and displayed on a liquid crystal display in real time.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an active matrix image sensor.

FIG. 2 is a diagram schematically illustrating an active matrix liquid crystal display.

FIG. 3 is a diagram schematically illustrating a conversion circuit.

FIG. 4 is a diagram showing a timing relationship between operations of an image sensor and a changeover switch.

FIG. 5 is a diagram schematically showing a digital still camera.

FIG. 6 is a block diagram showing a configuration of a digital still camera.

FIG. 7 is a diagram illustrating an outline of an information processing terminal.

FIG. 8 is a diagram showing a cross section of a structure in which a liquid crystal display and an image sensor are integrated.

FIG. 9 is a diagram showing a manufacturing process of a TFT in a structure in which a liquid crystal display and an image sensor are integrated.

[Explanation of symbols]

 401 glass substrate 402 glass substrate 403 polarizing plate 404 counter electrode 405 liquid crystal 406 active matrix circuit 407 polarizing plate 408 sealing material 409 active matrix circuit 410 space 411 lens support 412 lens 501 glass substrate 502 active layer 503 active layer 504 gate insulating film 505 gate electrode 506 gate electrode 507 drain region 508 channel region 509 source region 510 source region 511 channel region 512 drain region 513 interlayer insulating film (silicon oxide film) 514 drain electrode 515 source electrode 516 source electrode 517 drain electrode 518 interlayer insulating film ( (Acrylic resin film) 519 electrode 520 BM (black matrix) 521 photoelectric conversion layer (amorphous silicon film) 522 interlayer insulating film (acrylic resin) Film) 523 electrode 524 pixel electrode

Claims (11)

[Claims] 1. An image sensor comprising: an active matrix type image sensor; and an active matrix type liquid crystal display. The image sensor includes two unit pixels corresponding to one unit pixel of the liquid crystal display. The two unit pixels are arranged adjacent to each other, and at a predetermined timing, image information from the two unit pixels of the image sensor is continuously written to one unit pixel of the liquid crystal display. An electro-optical device, wherein one of the outputs from the unit pixels is input to the liquid crystal display with its polarity inverted with respect to the other output. 2. The electro-optical device according to claim 1, wherein signal waveforms including image information from two unit pixels are similar to each other. 3. The unit according to claim 1, wherein one unit pixel of the arbitrarily selected liquid crystal display and two unit pixels of the image sensor corresponding to the unit pixel are located in respective active matrix circuits. Are in correspondence with each other. 4. The liquid crystal display according to claim 1, wherein one unit pixel of the liquid crystal display arbitrarily selected and two unit pixels of the image sensor corresponding to the unit pixel are captured by the image sensor. An electro-optical device corresponding to the same portion of an image displayed by the method. 5. The electro-optical device according to claim 1, wherein an active element is disposed in each unit pixel in the active matrix type image sensor and the active matrix type liquid crystal display. 6. An active matrix type image sensor having 2N unit pixels, and an active matrix type liquid crystal display having N unit pixels, wherein N units are arranged in the image sensor. An electro-optical device, wherein a signal output from a pixel is input to the liquid crystal display via a circuit for inverting the polarity of a signal output from another unit pixel. 7. An active matrix type image sensor having 2N unit pixels, and an active matrix type liquid crystal display having N unit pixels, wherein the image sensor has N output units. And a unit pixel for inverted output and N unit pixels for inverted output are arranged, and the unit pixel for forward output and the unit pixel for inverted output are arranged adjacent to each other. apparatus. 8. The image sensor according to claim 7, wherein a unit pixel for forward output and two unit pixels for inversion output are arranged as a set corresponding to an arbitrary pixel of the liquid crystal display. The image information output from the two unit pixels is continuously written to any one pixel of the liquid crystal display at an arbitrary timing, and the signals including the image information from the two unit pixels are similar, An electro-optical device having the opposite polarities. 9. The electro-optical device according to claim 7, wherein an active element is disposed in each unit pixel in the active matrix type image sensor and the active matrix type liquid crystal display. 10. A method for displaying an image captured by an active matrix type image sensor on an active matrix type liquid crystal display, wherein the image sensor has two units corresponding to one unit pixel of the liquid crystal display. Pixels are arranged, and in any one unit pixel of the liquid crystal display, (1) a step of writing predetermined image information at a predetermined timing, and (2) a step of writing predetermined image information in the step of (1). And writing image information similar to the image information after holding the image information for a predetermined period. The two signals including the image information in the steps (1) and (2) are the two unit pixels Wherein the polarities are opposite to each other. 11. The image sensor according to claim 10, wherein the two unit pixels of the image sensor are arranged adjacent to each other, and the two signals including the image information in the steps (1) and (2) have waveforms thereof. An operation method of an electro-optical device, which is similar.