JP2008186882A - Photodetector and electro-optic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photodetector forming an optical sensor only by taking a step of introducing one of N-type and P-type impurities as an impurity introduction step, and also to provide an electro-optic device including the optical detector. <P>SOLUTION: In a sensor circuit 310 of the photodetector 300, a main sensor 310A and a sub sensor 310B include: a semiconductor film 1w having a highly concentrated N-type first impurity introduced region 1y and a second impurity introduced region 1z formed on both sides of an intrinsic region 1x; and a translucent bias applying electrode 5a opposing the intrinsic region 1x through an insulation layer 4a, thus having the same structure as that of a thin film transistor. By applying voltage in the direction of turning OFF the thin film transistor to the bias applying electrode 5a and also applying predetermined voltage to between the first and second regions 1y and 1z, photocurrent flows when light is incident to the intrinsic region 1x. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light detection device and an electro-optical device including the light detection device.

  Electronic devices such as personal computers and mobile phones equipped with an electro-optical device as a display device are used in various environments with different ambient light intensities. Accordingly, if the driving conditions in the electro-optical device are changed in accordance with changes in the ambient light, it is possible to improve image quality and reduce power consumption.

For example, in a transmissive or anti-transmissive liquid crystal device, a backlight device is provided on the back surface of the liquid crystal panel, and light emitted from the backlight device is modulated by the liquid crystal panel. In such a liquid crystal device, the power consumption of the backlight device is large. Therefore, it is proposed to install a light sensor consisting of discrete components in the liquid crystal device, measure the ambient light with this light sensor, adjust the intensity of the backlight device according to the measurement result, and reduce power consumption (For example, refer to Patent Document 1).
JP 2003-78838 A

  However, the technique described in Patent Document 1 has a problem that man-hours and costs increase because an optical sensor made of discrete components is mounted on a flexible substrate.

  Therefore, a PIN structure optical sensor in which a P-type region, an intrinsic region, and an N-type region are formed in a semiconductor film using a process of forming a thin film transistor (TFT / Thin Film Transistor) on an element substrate of a liquid crystal panel is provided. It is conceivable to form on a substrate, and according to such a configuration, man-hours and costs can be reduced as compared with the case of using an optical sensor made of discrete components.

  However, in order to form an optical sensor having a PIN structure on an element substrate, a process of introducing an N-type impurity and a process of introducing a P-type impurity are necessary. For example, a single conductivity type is formed on the element substrate. When only a thin film transistor is formed, it is necessary to newly add a step of introducing a P-type impurity. Accordingly, the PIN structure optical sensor has a problem that the cost cannot be further reduced.

  In view of the above problems, an object of the present invention is to provide an optical sensor capable of forming an optical sensor by performing only the step of introducing one of N-type and P-type impurities as the impurity introduction step. It is an object of the present invention to provide a detection device and an electro-optical device including the light detection device.

  In order to solve the above problems, the present invention provides a photodetection device in which a photosensor is formed on a substrate, and the photosensor has the same conductivity type on both sides of an intrinsic region formed on the substrate. A semiconductor film in which a first impurity introduction region and a second impurity introduction region are formed, and a bias applying electrode made of a translucent conductive film facing the intrinsic region via an insulating layer, A predetermined voltage is applied between the first impurity introduction region and the second impurity introduction region, and the bias application electrode includes the bias application electrode, the first impurity introduction region, and the first impurity introduction region. A voltage for applying an off state to the thin film transistor including the two impurity introduction regions is applied.

  The “intrinsic region” in the present invention is meant to include not only a region in which no impurity is introduced but also a region in which an impurity of a channel doping level performed in a thin film transistor is introduced.

  In the present invention, the optical sensor is opposite to the intrinsic region with an insulating layer interposed between the semiconductor film in which the first impurity introduction region and the second impurity introduction region having the same conductivity type are formed on both sides of the intrinsic region. And a bias applying electrode made of a translucent conductive film, and has the same structure as the thin film transistor. Therefore, in the optical sensor, when a voltage in a direction to turn off the thin film transistor is applied to the bias applying electrode, and a predetermined voltage is applied between the first impurity introduction region and the second impurity introduction region. When light is incident on the intrinsic region, a photocurrent flows. Therefore, light detection can be performed without using a PIN structure optical sensor, even with an optical sensor provided with one of the N-type and P-type impurity introduction regions. Therefore, the optical sensor can be formed even when only the step of introducing one of the N-type and P-type impurities is performed as the impurity introduction step, and man-hours and costs can be reduced. In addition, in the optical sensor to which the present invention is applied, a bias applying electrode facing the intrinsic region through an insulating layer is essential, and there is a bias applying electrode on the light incident side with respect to the intrinsic region. In the present invention, since the bias applying electrode is made of a translucent conductive film such as an ITO (Indium Tin Oxide) film, light is efficiently incident on the intrinsic region through the bias applying electrode. Therefore, the photodetection device has sufficient sensitivity.

  In the present invention, it is preferable that the semiconductor film is a polysilicon film, and the optical sensor is laminated on the substrate in the order of the semiconductor film, the insulating film, and the bias applying electrode. With such a configuration, an optical sensor can be manufactured using a manufacturing process of a thin film transistor using a polysilicon film as an active layer. In addition, the polysilicon film can be formed by a low temperature process, and there is an advantage that the sensitivity of the photosensor is higher when the polysilicon film is used than when an amorphous silicon film that can be formed by the low temperature process is used.

  In the present invention, it is preferable that a plurality of thin film transistors be formed on the substrate, and the plurality of thin film transistors have the same conductivity type as the first impurity introduction region and the second impurity introduction region.

  In the present invention, the insulating layer may be formed of the same insulating film as the gate insulating films of the plurality of thin film transistors. With this configuration, a bias can be suitably applied to the intrinsic region from the bias application electrode.

  In the present invention, the insulating layer may include one or more interlayer insulating films formed on the upper layer side of the plurality of thin film transistors. In an electro-optical device such as a liquid crystal device, a structure in which a pixel electrode is formed with a light-transmitting conductive film on an interlayer insulating film formed on an upper layer of a thin film transistor is often used. If a structure in which a bias applying electrode made of a conductive film is formed is employed, the bias applying electrode and the pixel electrode can be formed simultaneously. Therefore, the number of steps and cost can be reduced.

  In the present invention, the interlayer insulating film has a recess formed by removing or thinning a portion overlapping the intrinsic region, and the bias application electrode is opposed to the intrinsic region at the bottom of the recess. Is preferred. With this configuration, even when the bias applying electrode is formed on the interlayer insulating film, the insulating layer interposed between the bias applying electrode and the intrinsic region is thin. Therefore, a bias can be suitably applied to the intrinsic region from the bias application electrode.

  In the present invention, when the substrate is a light-transmitting substrate, a light-blocking layer is formed at least in a region overlapping with the intrinsic region on the side where the light-transmitting substrate is located with respect to the semiconductor film. preferable. If comprised in this way, it can prevent disturbance light from entering from the back surface side of a translucent board | substrate, and can improve the sensitivity of a photon detection apparatus.

  In the present invention, when the substrate is a light-transmitting substrate, the side where the light-transmitting substrate is located with respect to the semiconductor film is opposed to a region including the intrinsic region via a light-transmitting layer. A reflective layer is preferably formed. With this configuration, light obliquely incident on the reflective layer from the bias application electrode side can be guided to the intrinsic region, so that the sensitivity of the photodetector can be increased.

  In the present invention, the optical sensor includes a main sensor on which target light is incident and a sub sensor on which disturbance light is incident, and the main sensor and the sub sensor are electrically connected in series via a node to form a sensor. It is preferable that a circuit is configured and the intensity of the target light is detected based on a current or voltage taken from the node when a voltage is applied to both ends of the sensor circuit. If comprised in this way, only the intensity | strength of object light can be measured. In the present invention, “target light” means light to be detected, for example, environmental light (external light) in the embodiment. On the other hand, in the present invention, “disturbance light” means light that is not a detection target, and corresponds to, for example, the background light of the embodiment.

  In such a configuration, when the substrate is a light-transmitting substrate, the intrinsic sensor used for the main sensor among the main sensor and the sub sensor is disposed on the side where the substrate is located with respect to the semiconductor film. It is preferable that a reflective layer that is opposed to the region including the region through the light-transmitting layer is formed. With this configuration, light obliquely incident on the reflection layer from the bias application electrode side can be guided to the intrinsic region of the main sensor, and thus the sensitivity of the light detection device can be increased.

  The light detection device to which the present invention is applied can be used for an electro-optical device having a display area composed of a plurality of pixels. In this case, the drive condition in the display area is based on the light detection result by the light detection apparatus. It is preferable to adjust.

  The light detection device to which the present invention is applied can be used for an electro-optical device that includes a display region including a plurality of pixels and a light source that emits light to the display region. It is preferable to control the amount of light emitted from the light source based on the light detection result.

  The electro-optical device to which the present invention is applied can be used in electronic devices such as personal computers, mobile phones, and portable information terminals.

  The present invention will be described below with reference to the drawings. In the following embodiments, a light detection device according to the present invention is configured in a TFT active matrix driving type liquid crystal device which is a typical electro-optical device. In the drawings to be referred to in the following description, the scales are different for each layer and each member so that each layer and each member have a size that can be recognized on the drawing.

[Embodiment 1]
(overall structure)
FIG. 1 is a block diagram showing an electrical configuration of an electro-optical device to which the present invention is applied. An electro-optical device 100 shown in FIG. 1 is a totally transmissive liquid crystal device, and includes a liquid crystal panel 100p, an image processing circuit 202, a timing generation circuit 203, a power supply circuit 201, a dimming circuit 500, and a backlight device 600 (light source device). Etc. The image processing circuit 202, the timing generation circuit 203, and the power supply circuit 201 are configured by an IC or the like mounted on the flexible substrate 108 (see FIGS. 2A and 2B) connected to the liquid crystal panel 100p. The light control circuit 500 and the backlight device 600 are configured outside the liquid crystal panel 100p.

  In the timing generation circuit 203, a dot clock for driving each pixel 100a of the liquid crystal panel 100p is generated, and based on the dot clock, clock signals VCK, HCK, inverted clock signals VCKB, HCKB, transfer start pulses HSP, VSP. Is generated. When input image data is input from the outside, the image processing circuit 202 generates an image signal based on the input image data and supplies it to the liquid crystal panel 100p. The power supply circuit 201 generates a plurality of power supplies VDD, VSS, VHH, and VLL and supplies them to the liquid crystal panel 100p.

  The liquid crystal panel 100p includes a pixel array region 10b in which a plurality of pixels 100a are arrayed in a central region. In the liquid crystal panel 100p, on the element substrate 10 described later, a plurality of data lines 6a and a plurality of scanning lines 3a extend vertically and horizontally inside the pixel array region 10b, and the pixel is located at a position corresponding to the intersection of them. 100a is configured. In each of the plurality of pixels 100a, a thin film transistor 30 as a pixel switching element and a pixel electrode 9a are formed. The data line 6 a is electrically connected to the source of the thin film transistor 30, the scanning line 3 a is electrically connected to the gate of the thin film transistor 30, and the pixel electrode 9 a is electrically connected to the drain of the thin film transistor 30.

  In the element substrate 10, a scanning line driving circuit 104 and a data line driving circuit 101 are configured outside the pixel array region 10 b. The data line driving circuit 101 is electrically connected to the data line 6a and sequentially supplies image signals to the data lines 6a. The scanning line driving circuit 104 is electrically connected to the scanning line 3a, and sequentially supplies the scanning signal to each scanning line 3a.

  In each pixel 100a, the pixel electrode 9a is opposed to a common electrode formed on a counter substrate, which will be described later, via liquid crystal, and constitutes a liquid crystal capacitor 50a. Each pixel 100a is provided with a holding capacitor 60 in parallel with the liquid crystal capacitor 50a in order to prevent the image signal held in the liquid crystal capacitor 50a from leaking. In this embodiment, in order to form the storage capacitor 60, the capacitor line 3b is formed in parallel with the scanning line 3a, and the capacitor line 3b is connected to a common potential line (not shown) and has a predetermined potential. Is held in. The storage capacitor 60 may be formed between the preceding scanning line 3a.

  In the electro-optical device 100, the visibility of the display image depends on the brightness of the environment. For example, under natural daylight, it is necessary to set the light emission luminance of the backlight device 600 high and display a bright screen. On the other hand, in a dark environment at night, a clear image can be displayed even if the light emission luminance of the backlight device 600 is not as high as during the daytime. Therefore, it is desirable to adjust the light emission luminance of the backlight device 600 according to the illuminance of the ambient light. Therefore, the electro-optical device 100 according to the present embodiment includes a light detection device 300 including a sensor circuit 310 and a detection circuit 340. The light detection device 300 measures the illuminance of ambient light. In addition, the dimming circuit 500 controls the backlight device 600 to emit light with a luminance corresponding to the illuminance data obtained by the light detection device 300. A specific configuration of the light detection apparatus 300 will be described later. Note that the detection device 340 may be configured on the element substrate 10.

(Specific configuration of the liquid crystal panel 100p)
FIGS. 2A and 2B are a plan view of the liquid crystal panel 100p of the electro-optical device 100 to which the present invention is applied as viewed from the side of the counter substrate together with each component, and a cross-sectional view thereof taken along line HH ′. . As shown in FIGS. 2A and 2B, in the liquid crystal panel 100p of the electro-optical device 100, the element substrate 10 and the translucent counter substrate 20 made of glass or the like through a predetermined gap are provided. Is bonded by a sealing material 107 (a region with a slanting line in the lower right in FIG. 2A), and the sealing material 107 is disposed along the outer peripheral edge of the counter substrate 20. The sealing material 107 is an adhesive made of a photo-curing resin, a thermosetting resin, or the like, and is mixed with a gap material such as glass fiber or glass beads for setting the distance between both substrates to a predetermined value. In a corner portion of the counter substrate 20 and the like, a vertical conductive material (not shown) is formed for electrical conduction between the element substrate 10 and the counter substrate 20.

  In the element substrate 10, a data line driving circuit 101 and a plurality of terminals 102 are formed along one side of the element substrate 10 in a region outside the inner peripheral edge of the sealing material 107, and along the side adjacent to this one side. A scanning line driving circuit 104 is formed. In addition, a flexible substrate 108 is connected to the element substrate 10 by a terminal 102. The element substrate 10 may include a protection circuit and an inspection circuit for protecting the pixel array region 10b, the data line driving circuit 101, and the scanning line driving circuit 104 from static electricity, but the description thereof is omitted. To do.

  As will be described in detail later, pixel electrodes 9 a are formed in a matrix on the element substrate 10. On the other hand, the counter substrate 20 is formed with a frame-shaped light-shielding film 23b (a region with a diagonal line rising to the right in FIG. 2A) in the inner region of the sealant 107, and the inner side is the image display region. 10a. In the counter substrate 20, a light shielding film 23 a called a black matrix or a black stripe is formed in a region facing the vertical and horizontal boundary regions of the pixel electrode 9 a of the element substrate 10, and an ITO film is formed on the upper layer side. The counter electrode 21 is formed. In the pixel array area 10b, a dummy pixel may be formed in an area overlapping with the light shielding film 23b. In this case, an area excluding the dummy pixel in the pixel array area 10b is used as the image display area 10a. Will be. In this embodiment, since the photocurable adhesive is used as the sealing material 107, the light shielding film 23b and the sealing material 107 are formed at positions shifted so that light irradiation from the counter substrate 20 side is possible. When the sealant 107 is photocured by light irradiation from the element substrate 10 side, or when a thermosetting adhesive is used for the sealant 107, the light shielding film 23b and the sealant 107 are formed at the overlapping position. It is also possible to adopt the configuration.

  A liquid crystal 50 as an electro-optical material is sealed in a space surrounded by the sealing material 107. The liquid crystal 50 takes a predetermined alignment state by the alignment films 16 and 22 (see FIG. 2B) formed on the element substrate 10 and the counter substrate in a state where an electric field from the pixel electrode 9a is not applied. The liquid crystal 50 is made of, for example, one or a mixture of several types of nematic liquid crystals.

  In the electro-optical device 100, a backlight device 600 is disposed on the back side of the element substrate 10, and light emitted from the backlight device 600 is incident on the liquid crystal panel 100p from the element substrate 10 side to face the counter substrate. The light is modulated while being emitted from the side 20, and is emitted as display light from the side of the counter substrate 20. As the backlight device 600, a surface light source device can be adopted, and a light source device using an LED element and a light guide plate can also be adopted.

  In the liquid crystal panel 100p, a sensor circuit 310 is disposed at a position facing the data line driving circuit 101 with the image display region 10a interposed therebetween. In the present embodiment, the sensor circuit 310 includes a main sensor 310A and a sub sensor 310B that are light receiving elements formed on the element substrate 10. Here, a part of the light shielding film 23b formed on the counter substrate 20 is cut out, and in the element substrate 10, the main sensor 310A is formed in a region overlapping the notch 23c of the light shielding film 23b. On the other hand, the sub sensor 310B is formed in a region covered with the light shielding film 23b. Therefore, the main sensor 310A includes external light (environmental light) that is detection target light and disturbance light that is not a detection target (light emitted from the backlight device 600 and incident via the element substrate 10). Incident. On the other hand, since only disturbance light is incident on the sub sensor 310B, the intensity of external light can be detected by obtaining the difference between the detection result of the main sensor 310A and the detection result of the sub sensor 310B. . In this embodiment, the main sensor 310A is disposed at a position close to the image display area 10a, and the sub sensor 310B is disposed on the opposite side of the image display area 10a with respect to the main sensor 310A. Good. Further, the main sensor 310A and the sub sensor 310B may be arranged in series along the side of the image display area 10a. In this case, the main sensor 310A and the sub sensor 310B are equivalent to the image display area 10a. So that the incidence of disturbance light can be made equal.

  The electro-optical device 100 formed in this way can be used as a color display device for electronic devices such as a mobile computer, a mobile phone, and a liquid crystal television described later. In this case, a color filter (not shown) is provided on the counter substrate 20. ) And a protective film are formed. Further, on the light incident side surface or the light emitting side of the counter substrate 20 and the element substrate 10, the type of the liquid crystal 50 to be used, that is, an operation mode such as a TN (twisted nematic) mode, an STN (super TN) mode, Depending on the normally white mode / normally black mode, a polarizing film, a retardation film, a polarizing plate, and the like are arranged in a predetermined direction. The electro-optical device 100 is not limited to a transmissive type, and may be configured as a transflective type.

(Configuration of each pixel)
3A and 3B are plan views of adjacent pixels in the element substrate 10 used in the electro-optical device 100 to which the present invention is applied, and electro-optics at positions corresponding to the AA ′ line. It is sectional drawing when the apparatus 100 is cut | disconnected.

  As shown in FIGS. 3A and 3B, the element substrate 10 is provided with a base protective film 12 made of a silicon oxide film or the like on the surface of a light-transmitting substrate 10d made of glass or the like. On the surface side, an N-channel thin film transistor 30 is formed at a position adjacent to the pixel electrode 9a. In the thin film transistor 30, a high concentration source region 1d, a low concentration source region 1b, a channel formation region 1g, a low concentration drain region 1c, and a high concentration drain region 1e are arranged in this order on the island-shaped semiconductor film 1a. The thin film transistor 30 has an LDD (Lightly Doped Drain) structure. A gate insulating film 2 made of a silicon oxide film or the like is formed above the semiconductor film 1a, and a scanning line 3a is formed above the gate insulating film 2. A part of the scanning line 3a faces the channel formation region 1g through the gate insulating film 2 as a gate electrode.

The semiconductor film 1a is a polysilicon film that is polycrystallized by laser annealing, lamp annealing, or the like after an amorphous silicon film is formed on the translucent substrate 10d. The low-concentration source region 1b and the low-concentration drain region 1c are low-concentration N-type, for example, with a dose of about 0.1 × 10 ¹³ / cm ² to about 10 × 10 ¹³ / cm ^{2 using} the scanning line 3a as a mask. It is a semiconductor region formed by introducing impurities (such as phosphorus ions), and the high concentration source region 1d and the high concentration drain region 1e are about 0.1 × 10 ¹⁵ / cm ² to about 10 using a resist mask. This is a semiconductor region formed by introducing high-concentration N-type impurities (such as phosphorus ions) at a dose of × 10 ¹⁵ / cm ² .

  On the upper layer side of the thin film transistor 30, interlayer insulating films 7 and 8 are formed. A data line 6a and a drain electrode 6b are formed on the surface of the interlayer insulating film 7. The data line 6a is electrically connected to the high concentration source region 1d through a contact hole 7a formed in the interlayer insulating film 7. Yes. A pixel electrode 9 a made of an ITO film is formed on the surface of the interlayer insulating film 8. The pixel electrode 9 a is electrically connected to the drain electrode 6 b through the contact hole 8 a formed in the interlayer insulating film 8, and the drain electrode 6 b is connected to the contact hole formed in the interlayer insulating film 7 and the gate insulating film 2. 7b is electrically connected to the high concentration drain region 1e. An alignment film 16 made of a polyimide film is formed on the surface side of the pixel electrode 9a. For the extended portion 1f (lower electrode) from the high-concentration drain region 1e, the capacitive line 3b in the same layer as the scanning line 3a is provided via an insulating film (dielectric film) formed simultaneously with the gate insulating film 2. Are opposed to each other as an upper electrode, thereby forming a storage capacitor 60. In this embodiment, the scanning line 3a and the capacitor line 3b are formed of a single layer film or a laminated film such as a molybdenum film, an aluminum film, a titanium film, a tungsten film, or a tantalum film. The data line 6a and the drain electrode 6b are also formed of a single layer film or a laminated film such as a molybdenum film, an aluminum film, a titanium film, a tungsten film, or a tantalum film.

(Configuration of drive circuit)
4A and 4B are explanatory diagrams of a drive circuit formed on an element substrate used in an electro-optical device to which the present invention is applied, a plan view of a thin film transistor used in the drive circuit, and BB thereof, respectively. It is sectional drawing when an element substrate is cut | disconnected in the position equivalent to a 'line.

  2A again, in the electro-optical device 100 of the present embodiment, the data line driving circuit 101, the scanning line driving circuit 104, and the like are utilized by utilizing the peripheral region of the pixel array region 10b on the surface side of the element substrate 10. An internal circuit is formed. In configuring the data line driving circuit 101 and the scanning line driving circuit 104, a plurality of thin film transistors are used by using a manufacturing process of an N channel type thin film transistor 30 for pixel switching. As shown in FIG. 4A, only the N-channel thin film transistor 90 is used as the thin film transistor. In the circuit illustrated in FIG. 4A, a bootstrap capacitor 80 is used, and the bootstrap capacitor 80 is a capacitor formed simultaneously with the holding capacitor 60 shown in FIGS. 3A and 3B. . Therefore, the element substrate 10 is not formed with a P-channel type thin film transistor and is not formed with a P-type impurity introduction region.

4B and 4C, the thin film transistor 90 of the driving circuit is formed by using a part of the manufacturing process of the thin film transistor 30 for pixel switching, and the semiconductor film 1m constituting the thin film transistor 90 is A polysilicon film formed simultaneously with the semiconductor film 1a of the thin film transistor 30. In the semiconductor film 1m, a high concentration source region 1n, a low concentration source region 1s, a channel formation region 1r, a low concentration drain region 1t, and a high concentration drain region 1p are arranged in this order from the source side to the drain side. The thin film transistor 90 has an LDD structure. The low-concentration source region 1s and the low-concentration drain region 1t are, for example, about 0.1 × 10 ¹³ / cm using the gate electrode 3e as a mask when forming the low-concentration source region 1b and the high-concentration drain region 1c of the thin film transistor 30. A semiconductor region formed by introducing a low concentration N-type impurity (such as phosphorus ions) at a dose of ² to about 10 × 10 ¹³ / cm ^2. The high concentration source region 1 n and the high concentration drain region 1 p When forming the high-concentration source region 1d and the high-concentration drain region 1e of the thin film transistor 30, the resist mask is used to form a high concentration at a dose of about 0.1 × 10 ¹⁵ / cm ² to about 10 × 10 ¹⁵ / cm ^2. It is a semiconductor region formed by introducing an N-type impurity (such as phosphorus ion). Note that the thin film transistor 90 may be formed in a multi-gate structure. A gate insulating film 2 made of a silicon oxide film or the like is formed above the semiconductor film 1m, and a gate electrode 3e is formed above the gate insulating film 2.

  Interlayer insulating films 7 and 8 are formed on the upper layer side of the thin film transistor 90. In the thin film transistor 90, the wirings 6f and 6g are electrically connected to the high concentration source region 1n and the high concentration drain region 1p through contact holes 7f and 7g penetrating the interlayer insulating film 7 and the gate insulating film 2. The gate electrode 3e is a metal film formed simultaneously with the scanning line 3a and the capacitor line 3b, and is formed of a single layer film or a laminated film such as a molybdenum film, an aluminum film, a titanium film, a tungsten film, or a tantalum film. The wirings 6f and 6g are metal films formed simultaneously with the data lines 6a and the drain electrodes 6b, and are made of a single layer film or a laminated film such as a molybdenum film, an aluminum film, a titanium film, a tungsten film, or a tantalum film.

(Configuration of light detection device and its principle)
FIGS. 5A and 5B are a plan view of a sensor circuit used in the photodetection device to which the present invention is applied and a cross-sectional view taken along the line C-C ′. FIG. It is shown. 6A and 6B are explanatory diagrams showing the electrical configuration of the sensor circuit used in the photodetection device to which the present invention is applied. FIGS. 7A and 7B are explanatory diagrams of a detection circuit of a photodetection device to which the present invention is applied. The thin film transistor 30 for pixel switching has substantially the same configuration as the thin film transistor 90, and is different only in that the pixel electrode 9a is connected to the drain electrode via the contact hole 8a. For this reason, in FIG. 5, the reference numerals of the portions related to the thin film transistor 30 are given in parentheses, and the pixel electrode 9a and the contact hole 8a are indicated by dotted lines.

  As shown in FIGS. 5A and 5B, in this embodiment, the light detection device 300 includes a main sensor 310 </ b> A and a sub sensor 310 </ b> B as the sensor circuit 310. On the counter substrate 20, a light shielding film 23b is formed in a region overlapping the sub sensor 310B in a plane, and a notch 23c of the light shielding film 23b is located in a region overlapping the main sensor 310A in a plane. Therefore, external light (indicated by an arrow P) from the counter substrate 20 side and disturbance light from the element substrate 10 side are incident on the main sensor 310A, but external light is incident on the sub sensor 310B. Only ambient light is incident.

  In the present embodiment, the main sensor 310A and the sub sensor 310B have the same structure, and both the main sensor 310A and the sub sensor 310B have the first impurity introduction region 1y and the second sensor on both sides of the intrinsic region 1x. A semiconductor film 1w including the impurity introduction region 1z, an insulating layer 4a covering the semiconductor film 1w, and a bias applying electrode 5a facing the intrinsic region 1x via the insulating layer 4a are provided. Both the first impurity introduction region 1y and the second impurity introduction region 1z are high-concentration N-type regions. The bias application electrode 5a overlaps with the region including the intrinsic region 1x, the boundary region between the intrinsic region 1x and the first impurity introduction region 1y, and the boundary region between the intrinsic region 1x and the second impurity introduction region 1z. It also overlaps.

  Interlayer insulating films 7 and 8 are formed on the upper side of the bias applying electrode 5a. A wiring 6h formed in the upper layer of the interlayer insulating film 7 is electrically connected to the first impurity introduction region 1y of the main sensor 310A through a contact hole 7h. In the second impurity introduction region 1z of the main sensor 310A and the first impurity introduction region 1y of the sub sensor 310B, the wiring 6i formed in the upper layer of the interlayer insulating film 7 is electrically connected via the contact holes 7i and 7j. Connected. A wiring 6k formed in the upper layer of the interlayer insulating film 7 is electrically connected to the second impurity introduction region 1z of the sub sensor 310B through a contact hole 7k.

Here, the semiconductor film 1w is a polysilicon film formed simultaneously with the semiconductor films 1a and 1m constituting the thin film transistors 30 and 90. The first impurity introduction region 1y and the second impurity introduction region 1z are formed by using a resist mask when the high concentration source regions 1d and 1n and the high concentration drain regions 1e and 1p of the thin film transistors 30 and 90 are formed. This is a semiconductor region formed by introducing high-concentration N-type impurities (such as phosphorus ions) at a dose of 0.1 × 10 ¹⁵ / cm ² to about 10 × 10 ¹⁵ / cm ² . The insulating layer 4a is made of a silicon oxide film formed simultaneously with the gate insulating film 2. The wirings 6h, 6i, and 6k are metal films formed simultaneously with the wirings 6f and 6g, the data line 6a, and the drain electrode 6b. It consists of a laminated film.

  In this embodiment, the bias applying electrode 5a is made of an ITO film (translucent conductive film), and only the bias applying electrode 5a is a thin film newly added to form the main sensor 310A and the sub sensor 310B. .

  Both the main sensor 310A and the sub sensor 310B configured as described above have the same structure as the thin film transistor, and the bias application electrode 5a, the insulating layer 4a, the first impurity introduction region 1y, and the second impurity introduction. Each region 1z corresponds to a gate electrode, a gate insulating film, a source region, and a drain region of the thin film transistor. Therefore, in this embodiment, as shown in FIGS. 6A and 6B, the main sensor 310A and the sub sensor 310B are electrically connected in series via the node Q to form the sensor circuit 310, and Voltages VH and VL are applied across the sensor circuit 310. For example, 6V (voltage VH) is applied to the first impurity introduction region 1y (wiring 6h) of the main sensor 310A, and 0V (voltage VL) is applied to the second impurity introduction region 1z (wiring 6k) of the sub sensor 310B. To do. As a result, the voltage at the node Q becomes 3V in a state where light does not enter the main sensor 310A and the sub sensor 310B.

  In the main sensor 310A and the sub sensor 310B, voltages V1 and V2 in a direction to turn off the thin film transistor are applied to the bias applying electrodes 5a when the main sensor 310A and the sub sensor 310B are regarded as thin film transistors. . In this embodiment, since the main sensor 310A and the sub sensor 310B are N-type, for example, as shown in FIG. 6A, the bias application electrode 5a of the main sensor 310A and the second impurity of the sub sensor 310B are used. The introduction region 1z (wiring 6k) is electrically connected, and 0V (voltage VL) is applied to the bias application electrode 5a of the main sensor 310A, while -3V (−3 V) is applied to the bias application electrode 5a of the sub sensor 310B. Voltage VB) is applied.

  Further, as shown in FIG. 6B, predetermined voltages V1 and V2 are applied to the bias application electrodes 5a of the main sensor 310A and the sub sensor 310B, respectively, to increase the sensitivity of the main sensor 310A and the sub sensor 310B. May be raised. Even in this case, the voltage difference between the bias applying electrode 5a and the second impurity introduction region 1z in the main sensor 310A is equal to the voltage difference between the bias applying electrode 5a and the second impurity introduction region 1z in the sub sensor 310B. Is preferred.

  In either case, as in the present embodiment, when the main sensor 310A and the sub sensor 310B are N-type, the bias application electrode 5a of the main sensor 310A has a second impurity introduction region 1z ( A voltage equal to or lower than the voltage applied to the wiring 6i) is applied, and a voltage equal to or lower than the voltage applied to the second impurity introduction region 1z (wiring 6k) of the sub sensor 310B is applied to the bias applying electrode 5a of the sub sensor 310B. To do.

  As shown in FIGS. 7A and 7B, a detection circuit 340 is connected to the node Q, and the detection circuit 340 receives external light and disturbance light (not shown) on the main sensor 310A. When disturbance light is incident on the sub sensor 310B, the current change and voltage change caused by the impedance balance between the main sensor 310A and the sub sensor 310B being broken are measured to detect the intensity of the external light. The example shown in FIG. 7A is an example in which current detection is performed from the node Q, and a current detection circuit 341 detects a current flowing between the node Q and a constant voltage power source of (VH−VL) / 2. . The example shown in FIG. 7B is an example in which voltage detection is performed from the node Q. Charge corresponding to the voltage change at the node Q is accumulated in the capacitor 346 and the voltage value is detected by the voltage detection circuit 347. Note that a switch 348 is connected in parallel to the capacitor 346, and the measurement is reset by releasing the charge accumulated in the capacitor 346 by opening and closing the switch 348. Among these detection methods, the current detection method detects a very small current and is therefore vulnerable to noise, whereas the voltage detection method has an advantage of being resistant to noise. In the case of the voltage detection method, when the voltage at the node Q changes, the bias voltage values at the main sensor 310A and the sub sensor 310B change, so that a current component that is not proportional to external light flows. Therefore, it is preferable to employ an optimum detection method according to the application.

(Manufacturing method of electro-optical device and photodetector)
A method for manufacturing the electro-optical device 100 and the light detection device 300 will be described with reference to FIG. 8 in addition to FIGS. FIGS. 8A to 8J show the thin film transistor 90 and the sensor circuit 310 (the main sensor 310A and the sub-sensor) on the element substrate 10 in the manufacturing process of the electro-optical device 100 and the light detection device 300 to which the present invention is applied. It is process sectional drawing which shows the manufacturing method of sensor 310B). 8A to 8J respectively correspond to FIG. 5B.

  First, as shown to Fig.8 (a), after preparing the translucent board | substrates 10d made from glass etc. which were cleaned by ultrasonic cleaning etc., a substrate temperature is 150-450 degreeC in a base | substrate protective film formation process. Under the conditions, a base protective film 12 made of a silicon oxide film is formed on the entire surface of the translucent substrate 10d by a method such as plasma CVD.

  Next, in the semiconductor film formation step, the semiconductor film 1 made of an amorphous silicon film is formed on the entire surface of the translucent substrate 10d under the temperature condition of the substrate temperature of 150 to 450 ° C. by plasma CVD, for example, 40 to 50 nm. Then, the semiconductor film 1 is polycrystallized by a laser annealing method or the like. Next, the semiconductor film 1 is patterned using a photolithography technique to form the semiconductor films 1m (1a) and 1w in an island shape as shown in FIG.

  Next, as shown in FIG. 8C, a gate insulating film 2 made of a silicon oxide film or the like is formed on the semiconductor film 1m (1a) using a CVD method or the like. As a result, the insulating layer 4a is simultaneously formed on the surface of the semiconductor film 1w. Although not shown in the drawing, after this process, an N-type impurity (phosphorus ion or the like) is implanted into the extended portion 1f of the semiconductor film 1a to form the storage capacitor 60 between the capacitor line 3b. An electrode is formed.

  Next, in the high concentration impurity introducing step, as shown in FIG. 8D, a resist mask 41 that partially covers the surfaces of the semiconductor films 1m (1a) and 1w is formed on the gate insulating film 2 and the insulating layer 4a. After the formation, high-concentration N-type impurities (such as phosphorus ions) are introduced into the semiconductor films 1m (1a) and 1w to form a high-concentration source region 1n (1d) and a high-concentration drain region, 1p (1e). Then, the first impurity introduction region 1y and the second impurity introduction region z are formed. As a result, an intrinsic region 1x is formed in the semiconductor film 1w between the first impurity introduction region 1y and the second impurity introduction region z. Next, the resist mask 41 is removed.

  Next, in the bias application electrode forming step, an ITO film is formed on the entire surface of the translucent substrate 10d, and then patterned using a photolithographic technique. As shown in FIG. 5a is formed. In this way, the main sensor 310A and the sub sensor 310B are formed.

  Next, in the gate electrode formation step, a metal film such as a molybdenum film, an aluminum film, a titanium film, a tungsten film, or a tantalum film is formed on the entire surface of the translucent substrate 10d, and then patterned using a photolithography technique, As shown in FIG. 8F, the scanning line 3a, the capacitor line 3b, and the gate electrode 3e are formed. As a result, the storage capacitor 60 is formed.

  Next, in the low-concentration impurity introduction step, as shown in FIG. 8G, a low-concentration source is introduced by introducing low-concentration N-type impurities (such as phosphorus ions) using the scanning line 3a and the gate electrode 3e as a mask. Region 1s (1b) and lightly doped drain region 1t (1c) are formed. As a result, the channel formation region 1r (1g) is formed in a self-aligned manner with respect to the scanning line 3a and the gate electrode 3e.

  Next, in the first interlayer insulating film forming step, as shown in FIG. 8H, an interlayer insulating film 7 made of a silicon oxide film or the like is formed using a CVD method or the like, and then a photolithography technique is used. Contact holes 7f (7a), 7g (7b), 7h, 7i, 7j, and 7k are formed.

  Next, in the wiring formation step, as shown in FIG. 8I, a metal such as a molybdenum film, an aluminum film, a titanium film, a tungsten film, a tantalum film, or a laminated film thereof is formed on the entire surface of the translucent substrate 10d. After the film is formed, patterning is performed using a photolithography technique to form wiring 6f (data line 6a), wiring 6g (drain electrode 6b), and wirings 6h, 6i, and 6k.

  Next, in the second interlayer insulating film forming step, as shown in FIG. 8J, the interlayer insulating film 8 having the contact holes 8a is formed. Here, when the interlayer insulating film 8 includes an inorganic insulating film such as a silicon oxide film, the contact hole 8a is formed using the photolithography technique after the film formation. In the case where the interlayer insulating film 8 contains a photosensitive resin, after the photosensitive resin is applied, exposure and development are performed to simultaneously form the contact hole 8a.

  Next, in the pixel electrode forming step, an ITO film is formed on the entire surface of the translucent substrate 10d and then patterned using a photolithography technique to form a pixel electrode 9a as shown in FIG. 3B. . Next, an alignment film 16 shown in FIG. 3B is formed. As a result, the element substrate 10 is completed.

(Effect of this embodiment)
As described above, in the electro-optical device 100 and the light detection device 300 to which the present invention is applied, the main sensor 310A and the sub sensor 310B are the first impurities in which high-concentration N-type impurities are introduced on both sides of the intrinsic region 1x. A bias applying electrode 5a made of an ITO film (translucent conductive film) opposed to the intrinsic region 1x through the insulating layer 4a and the semiconductor film 1w in which the introduction region 1y and the second impurity introduction region 1z are formed. And has the same structure as the thin film transistor. For this reason, in the main sensor 310A and the sub sensor 310B, a voltage in a direction to turn off the thin film transistor is applied to the bias applying electrode 5a, and between the first impurity introduction region 1y and the second impurity introduction region 1z. When a predetermined voltage is applied, a photocurrent flows when light enters the intrinsic region 1x. Therefore, even if the main sensor 310A and the sub sensor 310B having the high-concentration N-type first impurity introduction region 1y and the second impurity introduction region 1z are used without using a PIN structure photosensor, light detection can be performed. Can be done. Therefore, as the impurity introduction step, the main sensor 310A and the sub sensor 310B can be formed only by performing the high concentration N-type impurity introduction step, and the P-type impurity introduction step is not performed. Therefore, the main sensor 310A and the sub sensor 310B can be efficiently formed on the element substrate 10 as well. That is, the main sensor 310A and the sub sensor 310B can be efficiently formed on the element substrate 10 on which only the N-channel type thin film transistors 30 and 90 are formed as the thin film transistors, and the man-hours and costs can be reduced.

  Moreover, since the bias application electrode 5a facing the intrinsic region 1x via the insulating layer 4a is made of an ITO film (translucent conductive film), the light is applied to the intrinsic region 1x through the bias application electrode 5a. Efficiently enters. Therefore, the sensitivity of the main sensor 310A and the sub sensor 310B is high.

  Further, the semiconductor film 1w is a polysilicon film, and the main sensor 310A and the sub sensor 310B are laminated in the order of the semiconductor film 1w, the insulating layer 4a, and the bias applying electrode 5a when viewed from the light transmitting substrate 10d side. . Therefore, the main sensor 310A and the sub sensor 310B can be formed by using the manufacturing process of the thin film transistors 30 and 90. Further, since the semiconductor film 1w is a polysilicon film, it can be formed by a low-temperature process, and there is an advantage that the sensitivity of the main sensor 310A and the sub sensor 310B is higher than when an amorphous silicon film is used.

  Further, the insulating layer 4a is made of the same insulating film as the gate insulating film 2 of the thin film transistors 30 and 90, and is thin. For this reason, a bias can be suitably applied to the intrinsic region 1x from the bias applying electrode 5a.

[Embodiment 2]
FIG. 9 is a cross-sectional view of a sensor circuit used in the light detection device according to the second embodiment of the present invention, and FIG. 9 corresponds to FIG. 5 of the first embodiment. The basic configuration of this embodiment and the third and fourth embodiments described below is the same as that of the first embodiment, and therefore, parts having common functions are denoted by the same reference numerals and illustrated. Thus, the description thereof is omitted.

  As shown in FIG. 9, the light detection device 300 of this embodiment also has a main sensor 310 </ b> A to which ambient light (indicated by an arrow P) and ambient light are incident on the sensor circuit 310, as in Embodiment 1, and ambient light. The sub sensor 310B which injects. On the counter substrate 20, a light shielding film 23b is formed in a region overlapping the sub sensor 310B in a plane, and a notch 23c of the light shielding film 23b is located in a region overlapping the main sensor 310A in a plane.

  Each of the main sensor 310A and the sub sensor 310B includes a semiconductor film 1w having a first impurity introduction region 1y and a second impurity introduction region 1z on both sides of the intrinsic region 1x, an insulating layer 4b covering the semiconductor film 1w, A bias applying electrode 9b is provided opposite to the intrinsic region 1x via the insulating layer 4b. Here, the first impurity introduction region 1y and the second impurity introduction region 1z are both high-concentration N-type regions.

  In this embodiment, the insulating layer 4a includes an insulating film formed simultaneously with the gate insulating film 2 and the interlayer insulating films 7 and 8, and the bias applying electrode 9b is formed of the interlayer insulating film 8 in the same manner as the pixel electrode 9a. It consists of an ITO film formed in the upper layer.

  Similarly to the first embodiment, the light detection device 300 configured in this way also receives light by the main sensor 310A and the sub sensor 310B including the high-concentration N-type first impurity introduction region 1y and the second impurity introduction region 1z. The same effects as those of the first embodiment can be obtained, for example, detection can be performed. In this embodiment, the insulating layer 4b is considerably thicker than the insulating layer 4a formed in the first embodiment. However, if a voltage lower than that in the first embodiment is applied to the bias applying electrode 9b, the insulating layer 4b is much thicker. Good.

  In this embodiment, the bias applying electrode 9b is made of an ITO film formed on the interlayer insulating film 7 like the pixel electrode 9a. For this reason, the bias applying electrode 9b can be formed simultaneously with the pixel electrode 9a, so that the bias applying electrode forming step described with reference to FIG. 8E in the first embodiment can be omitted. . Note that when the low-concentration impurity introduction step described in Embodiment 1 with reference to FIG. 8G is performed, the formation region of the semiconductor film 1w may be covered with a resist mask.

  Further, in this embodiment, the side where the translucent substrate 10d is located with respect to the semiconductor film 1w, for example, the interlayer between the translucent substrate 10d and the base protective film 12 overlaps with the region including the intrinsic region 1x. A light shielding layer 11a made of a metal film such as a chromium film or titanium, a titanium nitride film, or the like is formed. For this reason, since the light from the backlight device 600 shown in FIG. 2B does not directly enter the intrinsic region 1x, the sensitivity of the main sensor 310A and the sub sensor 310B is high. In such a configuration, the light-shielding layer 11a is formed on the surface of the translucent substrate 10d by using a photolithography technique before the base protective film forming step described with reference to FIG. That's fine. Such a configuration may be applied to the first embodiment.

[Embodiment 3]
FIG. 10 is a cross-sectional view of the sensor circuit used in the photodetector according to Embodiment 3 of the present invention, and FIG. 10 corresponds to FIG. 5 of Embodiment 1.

  As shown in FIG. 10, the light detection device 300 of this embodiment also has a main sensor 310 </ b> A that receives external light (indicated by an arrow P) and disturbance light, and disturbance light as in the first embodiment. The sub sensor 310B which injects. On the counter substrate 20, a light shielding film 23b is formed in a region overlapping the sub sensor 310B in a plane, and a notch 23c of the light shielding film 23b is located in a region overlapping the main sensor 310A in a plane.

  Each of the main sensor 310A and the sub sensor 310B includes a semiconductor film 1w having a first impurity introduction region 1y and a second impurity introduction region 1z on both sides of the intrinsic region 1x, an insulating layer 4b covering the semiconductor film 1w, A bias applying electrode 9b is provided opposite to the intrinsic region 1x via the insulating layer 4b. Here, the first impurity introduction region 1y and the second impurity introduction region 1z are both high-concentration N-type regions.

  In this embodiment, an insulating film formed simultaneously with the gate insulating film 2 and the interlayer insulating films 7 and 8 is formed on the upper layer side of the semiconductor layer 1w, and the bias applying electrode 9b is the same as the pixel electrode 9a. It consists of an ITO film formed in the upper layer of the interlayer insulating film 8. However, in this embodiment, in the interlayer insulating film 8, a region overlapping with the intrinsic region 1x is removed, and a recess 8b is formed. Therefore, the bias applying electrode 9b is opposed to the intrinsic region 1x via the insulating layer 4c including the insulating film formed simultaneously with the gate insulating film 2 and the interlayer insulating film 7 at the bottom of the recess 8b. Therefore, as compared with the second embodiment, a bias can be suitably applied to the intrinsic region 1x from the bias applying electrode 9b. Such a recess 8 b can be formed simultaneously with the contact hole 8 a of the interlayer insulating film 8. In addition to the configuration in which the entire thickness of the interlayer insulating film 8 is removed, the recess 8b reaches the middle position in the thickness direction of the interlayer insulating film 8, and further reaches the interlayer insulating film 7. Alternatively, a configuration generated by forming a recess only in the interlayer insulating film 7 may be employed. Also in this embodiment, the light shielding layer 11a described with reference to FIG. 9 may be formed.

[Embodiment 4]
FIG. 11 is a cross-sectional view of the sensor circuit used in the photodetector according to Embodiment 4 of the present invention, and FIG. 11 corresponds to FIG. 5 of Embodiment 1.

  As shown in FIG. 11, the light detection device 300 of the present embodiment also has a main sensor 310 </ b> A that receives external light (indicated by an arrow P) and disturbance light, and disturbance light as in the first embodiment. The sub sensor 310B which injects. On the counter substrate 20, a light shielding film 23b is formed in a region overlapping the sub sensor 310B in a plane, and a notch 23c of the light shielding film 23b is located in a region overlapping the main sensor 310A in a plane.

  Each of the main sensor 310A and the sub sensor 310B includes a semiconductor film 1w having a first impurity introduction region 1y and a second impurity introduction region 1z on both sides of the intrinsic region 1x, an insulating layer 4a covering the semiconductor film 1w, A bias applying electrode 9b is provided opposite to the intrinsic region 1x via the insulating layer 4a. Here, the first impurity introduction region 1y and the second impurity introduction region 1z are both high-concentration N-type regions.

  In this embodiment, a region including the intrinsic region 1x of the main sensor 310A is provided on the back surface side of the translucent substrate 10d, that is, on the side where the backlight device 600 shown in FIG. The reflective layer 13a is formed from a film or sheet of aluminum or an aluminum-silver alloy so as to overlap. On the other hand, the reflective layer 13a is not formed on the sub sensor 310B side.

  If comprised in this way, it exists in the state which the reflective layer 13a has overlapped with the translucent layer which consists of the translucent board | substrate 10d and the base | substrate protective film 12 with respect to the area | region including the intrinsic area | region 1x of 310 A of main sensors. For this reason, as indicated by an arrow R, even when light incident obliquely from the counter substrate 20 side deviates from the intrinsic region 1x of the main sensor 310A, it is reflected by the reflective layer 13a and enters the intrinsic region 1x of the main sensor 310A. Incident. For this reason, there is an advantage that the sensitivity of the main sensor 310A is high. Such a configuration may be applied to the first to third embodiments.

[Application examples to other electro-optical devices]
In the above embodiment, the case where the main sensor 310A and the sub sensor 310B are of the N type has been described. However, the main sensor 310A and the sub sensor 310B may be configured of the P type, and in this case, the polarity of the voltage can be reversed. That's fine.

  In the above embodiment, the amount of light emitted from the backlight device is controlled based on the detection result of the light detection device 300 in the liquid crystal device, but is supplied to each pixel based on the detection result of the light detection device 300. The signal may be controlled. In the above embodiment, the liquid crystal device is described as an example of the electro-optical device. However, in the organic electroluminescence device, the signal supplied to each pixel is controlled based on the detection result of the light detection device 300. Good.

[Example of mounting on electronic devices]
Next, an electronic apparatus to which the electro-optical device 100 according to the above-described embodiment is applied will be described. FIG. 12A shows a configuration of a mobile personal computer including the electro-optical device 100. The personal computer 2000 includes an electro-optical device 100 as a display unit and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002. FIG. 12B shows a configuration of a mobile phone provided with the electro-optical device 100. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the electro-optical device 100 as a display unit. By operating the scroll button 3002, the screen displayed on the electro-optical device 100 is scrolled. FIG. 12C shows the configuration of a personal digital assistant (PDA) to which the electro-optical device 100 is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the electro-optical device 100 as a display unit. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the electro-optical device 100.

  As an electronic apparatus to which the electro-optical device 100 is applied, in addition to those shown in FIG. 12, a digital still camera, a liquid crystal television, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic notebook, Examples include calculators, word processors, workstations, videophones, POS terminals, devices with touch panels, and the like. The electro-optical device 100 described above can be applied as a display unit of these various electronic devices.

1 is a block diagram illustrating an electrical configuration of an electro-optical device to which the present invention is applied. (A), (b) is the top view which looked at the liquid crystal panel of the electro-optical apparatus to which this invention was applied from the opposing board | substrate side with each component, and its HH 'sectional drawing. (A), (b) is a plan view of adjacent pixels in the element substrate 10 used in the electro-optical device to which the present invention is applied, and the electro-optical device is cut at a position corresponding to the line AA ′. It is sectional drawing when doing. (A), (b) is an explanatory diagram of a drive circuit formed on an element substrate used in an electro-optical device to which the present invention is applied, a plan view of a thin film transistor used in this drive circuit, and its BB ′ line. It is sectional drawing when an element substrate is cut | disconnected in the position corresponded to. (A), (b) is the top view of the sensor circuit used for the photon detection device to which this invention is applied, and its CC 'sectional drawing. (A), (b) is explanatory drawing which shows the electrical structure of the sensor circuit used for the photon detection apparatus to which this invention is applied. (A), (b) is explanatory drawing of the detection circuit of the photon detection apparatus to which this invention is applied. FIG. 4 is a process cross-sectional view for forming a thin film transistor and a sensor circuit (a main sensor and a sub sensor) of a drive circuit on an element substrate in the manufacturing process of an electro-optical device and a light detection device to which the present invention is applied. It is sectional drawing of the sensor circuit used for the photon detection apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing of the sensor circuit used for the photon detection apparatus which concerns on Embodiment 3 of this invention. It is sectional drawing of the sensor circuit used for the photon detection apparatus which concerns on Embodiment 4 of this invention. It is explanatory drawing of the electronic device provided with the electro-optical apparatus to which this invention is applied.

Explanation of symbols

1w... Semiconductor film of optical sensor, 1y... First impurity introduction region of optical sensor, 1z... Second impurity introduction region of optical sensor, 4a, 4b, 4c .. insulating layer of optical sensor, 5a. 9b ··· Electrode for bias application of optical sensor, 10 · · Element substrate, 30 · · Thin film transistor for pixel switching, 90 · · Thin film transistor for driving circuit, 100 · · Electro-optical device, 300 · · Photodetector device · · · · Sensor circuit, 310A · · Main sensor, 310B · · Sub sensor, 340 · · Detection circuit, 500 · · Dimming circuit, 600 · · Backlight device

Claims (12)

A photodetection device in which a photosensor is formed on a substrate,
The optical sensor is insulated from the intrinsic region and a semiconductor film in which a first impurity introduction region and a second impurity introduction region having the same conductivity type are formed on both sides of the intrinsic region formed on the substrate. An electrode for bias application made of a translucent conductive film facing through a layer,
A predetermined voltage is applied between the first impurity introduction region and the second impurity introduction region,
A voltage for turning off a thin film transistor including the bias application electrode, the first impurity introduction region, and the second impurity introduction region is applied to the bias application electrode. apparatus. The semiconductor film is a polysilicon film;
2. The photodetecting device according to claim 1, wherein the optical sensor is formed by sequentially stacking the semiconductor film, the insulating film, and the bias applying electrode on the substrate. A plurality of thin film transistors are formed on the substrate,
The photodetection device according to claim 2, wherein the plurality of thin film transistors have the same conductivity type as the first impurity introduction region and the second impurity introduction region.   The photodetecting device according to claim 3, wherein the insulating layer is made of the same insulating film as a gate insulating film of the plurality of thin film transistors.   The photodetection device according to claim 3, wherein the insulating layer includes one or more interlayer insulating films formed on an upper layer side of the plurality of thin film transistors. In the interlayer insulating film, a recess formed by removing or thinning a portion overlapping the intrinsic region is formed,
The photo-detecting device according to claim 5, wherein the bias applying electrode is opposed to the intrinsic region at the bottom of the concave portion. The substrate is a translucent substrate;
The light shielding layer is formed in the area | region which overlaps with the said intrinsic area | region at least in the side in which the said translucent substrate is located with respect to the said semiconductor film. Light detection device. The substrate is a translucent substrate;
The reflective layer which opposes via the translucent layer with respect to the area | region containing the said intrinsic area | region is formed in the side in which the said translucent board | substrate is located with respect to the said semiconductor film. Any one of thru | or 6 is a photodetector. The optical sensor includes a main sensor on which target light is incident and a sub sensor on which disturbance light is incident,
The main sensor and the sub sensor are electrically connected in series via a node to constitute a sensor circuit,
8. The intensity of the target light is detected based on a current or voltage extracted from the node when a voltage is applied to both ends of the sensor circuit. 9. Photodetector. The substrate is a translucent substrate;
On the side where the substrate is positioned with respect to the semiconductor film, a reflective layer facing the region including the intrinsic region used for the main sensor, through the light-transmitting layer, of the main sensor and the sub sensor. The light detection device according to claim 9, wherein: An electro-optical device comprising: the light detection device according to claim 1; and a display region including a plurality of pixels.
An electro-optical device, wherein a driving condition in the display region is adjusted based on a light detection result by the light detection device.   11. An electro-optical device comprising: the light detection device according to claim 1; a display region including a plurality of pixels; and a light source that emits light to the display region. An electro-optical device that controls the amount of light emitted from the light source based on a light detection result by a detection device.

Images