Imaging device and display device

Abstract

To provide a semiconductor device that can acquire highly accurate distance information in a short time, and a semiconductor device that can acquire the distance information and image information at the same time.SOLUTION: The accuracy of the distance information is improved by performing irradiation with infrared light a plurality of times in order to acquire a detection signal, with an irradiation period in each irradiation being set to be the same and very short. The accuracy of the distance information can be kept even if a detection object is a mobile body, by causing adjacent photodiodes to detect the reflection light from the detection object from substantially the same point. The distance information and the image information can be acquired at the same time by providing the photodiode that absorbs visible light and transmits infrared light and the photodiode that absorbs the infrared light in the overlapping manner.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for driving a semiconductor device having a photosensor.

[0002] In this specification, a semiconductor device is a device that can function by utilizing semiconductor characteristics. Generally speaking, electro-optical devices, semiconductor circuits, and electronic devices are all semiconductor devices. [Background technology]

[0003] In recent years, many 3D distance measurement methods have been developed that can obtain not only shape information but also distance information of the detected object. These techniques are mainly divided into two types: active and passive. Active measurement methods irradiate the object to be detected with light, radio waves, sound waves, etc., and measure the Passive measurement methods use specific light or radio waves to assist in measurement, and are used to detect objects. Do not irradiate the target object.

[0004] Passive measurement techniques include the stereo matching method, and active measurement techniques include the time-of-flight method ( Time Of Flight (TOF) method, light section method, etc. The imaging method uses multiple optical sensors to capture different images and obtain distance information based on the principle of triangulation. In Patent Document 1, the following is obtained for an area smaller than the area commonly included in different images: By performing stereo matching, measurement time is shortened and measurement accuracy is improved.

[0005] The TOF method irradiates the object to be detected with infrared light for a certain period of time, and the reflected light is detected by each pixel of the optical sensor. The time difference between the time when the light irradiation started and the time when the reflected light reaches the light sensor is used. Using this, distance information is calculated from the irradiation period, the detection signal, and the speed of light. Two detection signals are obtained by irradiating infrared light. One advantage is that the device can be easily miniaturized.

[0006] In Patent Document 2, two-dimensional imaging and three-dimensional imaging are alternately performed for each frame period, Using pixels, two-dimensional information (intensity and color of reflected light from the detected object, etc.) and three-dimensional information (light The distance from the source to the detected object is acquired. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2008-59148 A [Patent Document 2] JP 2010-35168 A [Non-patent literature]

[0008] [Non-Patent Document 1] SJKim et al, “A Three-Dimensional Time-of-Flight CMOS Image Sensor With Pinned-Photodiode Pixel Structure”, IEEE Electron Device Letters, Nov. 2010, Vol. 31, No. 11, pp. 1272-1274 Summary of the Invention [Problem to be solved by the invention]

[0009] In the stereo matching method, in order to obtain highly accurate distance information, the matching accuracy is The increase in the amount of matching processing will result in a huge increase in measurement time. Since a large number of optical sensors must be disposed at distant positions, it is difficult to miniaturize the semiconductor device.

[0010] In addition, in the TOF method, the detection signal for calculating distance information is obtained by irradiating infrared light once. However, if the detection signal is not detected, the accuracy of the detection signal decreases.

[0011] In addition, in Non-Patent Document 1, between the acquisition of the first detection signal and the acquisition of the second detection signal, When the object to be detected moves, the detection signal is slightly shifted due to the time difference. It is difficult to maintain the accuracy of distance information.

[0012] In addition, in Patent Document 2, the frame period must be switched between two-dimensional imaging and three-dimensional imaging. Therefore, it is necessary to obtain information by two-dimensional imaging and information by three-dimensional imaging. There is a time lag between the two, making it difficult to obtain both pieces of information at the same time.

[0013] Therefore, one of the objectives is to provide a semiconductor device capable of acquiring highly accurate distance information in a short time. In addition, the semiconductor sensor can obtain highly accurate distance information in a short time even if the object to be detected moves. One of the objectives of the present invention is to provide a body device that can obtain highly accurate distance information and images in a short time. It is an object of the present invention to provide a semiconductor device capable of simultaneously acquiring information.

[0014] Another object is to reduce the size of a semiconductor device. [Means for solving the problem]

[0015] In one embodiment of the present invention, infrared light is irradiated multiple times to obtain one detection signal, and The accuracy of distance information is improved by making the irradiation period the same and extremely short for each time.

[0016] One embodiment of the present invention disclosed in this specification is a photoelectric conversion element and a method for producing the same. a pixel including a first transistor for storing a signal charge in an FD node based on the amount of the signal; A signal processing circuit that performs arithmetic processing based on the detection signal output from the A driving method, comprising: applying a potential to one electrode of a photoelectric conversion element such that an FD node is at a first high potential; The light source irradiates the object to be detected with infrared light for a period T. When the light reaches the object, it is reflected by the object. The light source stops irradiating infrared light from the time when the irradiated light starts to enter the photoelectric conversion element. During the first period until the time, the potential of the gate electrode of at least the first transistor is set to the second high This process is repeated n times (n is a natural number of 2 or more), and the FD noise after the nth first period is a first detection signal based on a first potential difference between the potential of the first node and the low potential is obtained from the output line; After acquiring the detection signal of 1, the FD node is set to a first high potential and the FD node is set to a second high potential. A potential is supplied to the object to be detected, and infrared light is irradiated from the light source to the object for a period T. From the time when the irradiation of the object is stopped, the light reflected from the object begins to enter the photoelectric conversion element. During the second period until the end of the second period, the potential of the gate electrode of at least the first transistor is The second high potential is repeated n times, and the potential of the FD node after the nth second period is compared with the low potential. A second detection signal based on a second potential difference between the potential is obtained from the output line, and the second detection signal is After acquisition, the signal is expressed as follows: the speed of light is c, the first detection signal is S1, and the second detection signal is S2. In the processing circuit, the following equation

number

[0017] Another embodiment of the present invention disclosed in this specification is a photoelectric conversion element, a method for producing a photoelectric conversion element using a photoelectric conversion element a first transistor for storing a signal charge in an FD node based on the amount of stored signal charge; a second transistor for amplifying the signal potential converted based on the amplified signal potential; A pixel including a third transistor for outputting a detection signal from an output line based on the detection signal, and a signal processing circuit for performing arithmetic processing based on the detected signal. A potential that sets the FD node to a first high potential is supplied to one electrode of the photoelectric conversion element. The infrared light is irradiated from the light source to the object to be detected for a period T. The infrared light reaches the object and is reflected. From the time when light starts to enter the photoelectric conversion element to the time when the light source stops irradiating infrared light During the first period, at least the potential of the gate electrode of the first transistor is set to the second high potential. This is repeated n times (n is a natural number equal to or greater than 2), and after repeating this n times, the first period of the nth time The potential of the FD node after the first transistor is amplified by the second transistor and the gate of the third transistor is A potential is supplied to the second transistor and the third transistor so that the second transistor and the third transistor are connected to the third high potential. After changing the potential of the output line by turning on the a potential difference between the potential of the output line after the low potential is supplied and the low potential is set to a first potential difference; After the output is made from the output line, a first detection signal is obtained based on the first potential difference, and a first After acquiring the detection signal, the FD node is set to a first high potential on one electrode of the photoelectric conversion element. A potential is supplied to the object to be detected, and infrared light is irradiated from the light source to the object for a period T. From the time when irradiation is stopped, the light that reaches the object and is reflected stops being incident on the photoelectric conversion element. During the second period until the time when the switching is completed, the potential of the gate electrode of at least the first transistor is set to the first The high potential of 2 is repeated n times, and after the nth repetition, the FD after the nth second period is The potential of the node is amplified by the second transistor, and the gate electrode of the third transistor is A potential serving as a third high potential is supplied to turn on the second transistor and the third transistor. After changing the potential of the output line by applying a voltage to the gate electrode of the third transistor, the potential of the gate electrode of the third transistor is set to a low potential. a second potential difference between the potential of the output line after the low potential is supplied and the low potential is supplied from the output line After the output, a second detection signal is obtained based on the second potential difference, and the second detection signal is After acquiring the signal, if the speed of light is c, the first detection signal is S1, and the second detection signal is S2, In the signal processing circuit, the following equation

number

[0018] In one embodiment of the present invention, infrared light is irradiated multiple times to obtain two detection signals. The reflected light from each detected object is detected by adjacent photodiodes without any time lag. By detecting the distance and keeping the irradiation period the same and extremely short, the accuracy of distance information is improved. The aim is to

[0019] One embodiment of the present invention disclosed in this specification is a photoelectric conversion element and a method for producing the same. A plurality of pixels each including a storage transistor that stores a signal charge in an FD node based on the amount of the output A signal processing circuit that performs arithmetic processing based on a detection signal output from the force line. A method for driving a detection device, comprising: irradiating an object to be detected with infrared light from a light source for a period T; The light that reaches the first photoelectric conversion element and is reflected by the second photoelectric conversion element adjacent to the first photoelectric conversion element. Before a first time when light starts being incident on the photoelectric conversion element, one electrode of the first photoelectric conversion element A potential is supplied to the first FD node so that the first FD node is at a high potential, and from a first time instant, the light source irradiates infrared light. During the period until the second time when the irradiation is stopped, at least the gate electrode of the first storage transistor The potential of the second photoelectric conversion element is set to a high potential, and before a second time, a second A potential is supplied to make the FD node a high potential, and from the second time, the reflected light that reaches the object to be detected is until a third time when the light stops being incident on the first photoelectric conversion element and the second photoelectric conversion element. The period is n in which the potential of the gate electrode of at least the second storage transistor is set to a high potential. (n is a natural number of 2 or more) times, and after repeating n times, the first A first detection signal based on a first potential difference between the potential of the FD node and a low potential is output from a first output line. a second potential difference between the potential of the second FD node and the low potential after the nth third time point; A second detection signal based on the first detection signal and the second detection signal is obtained from a second output line. After obtaining the signal, the speed of light is c, the first detection signal is S1, and the second detection signal is S2. The signal processing circuit uses the following formula:

number

[0020] Another embodiment of the present invention disclosed in this specification is a photoelectric conversion element, a method for producing a photoelectric conversion element using a photoelectric conversion element A storage transistor that stores signal charge in the FD node based on the amount of stored signal charge. an amplifier transistor for amplifying the signal potential converted based on the amplified signal potential; A plurality of pixels each including an output transistor that outputs a detection signal from an output line, A signal processing circuit that performs arithmetic processing based on the detected signal. The light source irradiates the object to be detected with infrared light for a period T. The light reaches the object and is reflected. The light is incident on a first photoelectric conversion element and a second photoelectric conversion element adjacent to the first photoelectric conversion element. A first FD is applied to one electrode of the first photoelectric conversion element before a first time when the first FD starts to be incident on the first photoelectric conversion element. A potential is supplied to make the node a high potential, and from a first time, the light source stops emitting infrared light. During the period up to the time of 2, the potential of the gate electrode of at least the first storage transistor is set to a high potential. Prior to a second time, a second FD node is connected to one electrode of a second photoelectric conversion element. A potential is supplied to the object to be detected, and from a second time, the light that reaches the object and is reflected becomes the first light. The period until the third time when the incidence of the light on the photoelectric conversion element and the second photoelectric conversion element is terminated is at least In both cases, the potential of the gate electrode of the second storage transistor is set to a high potential. After repeating n times, the power of the first FD node after the nth third time is The first amplifier transistor amplifies the signal, and the gate electrode of the first output transistor is driven high. A potential is supplied to the first amplifier transistor and the first output transistor to make them conductive. After changing the potential of the first output line by applying A potential to be a first low potential is supplied, and the potential of the first output line after the supply of the first low potential and the potential of the first A first potential difference with a low potential is output from the first output line, and a second F The potential of the D node is amplified by the second amplifier transistor, and the potential of the second output transistor is A potential is supplied to the output electrode of the second amplifier transistor and the output electrode of the second amplifier transistor. The potential of the second output line is changed by conducting the second output transistor. A potential is supplied to the gate electrode to set it to a second low potential, and after the second low potential is supplied, a second potential difference between the first potential and a second low potential is output from the second output line, and a second potential difference between the first potential and a second low potential is output from the first output line. After outputting the first potential difference from the second output line, a second potential difference is output from the second output line. a first detection signal is obtained based on the second potential difference, and a second detection signal is obtained based on the first detection signal; After acquiring the first detection signal and the second detection signal, the speed of light is c, the first detection signal is S1, and the second detection signal is When S2 is used, the signal processing circuit is

number

[0021] In the above, the plurality of pixels included in the semiconductor device each include a photoelectric conversion element and an object to be detected. It is preferable to calculate the distance

[0022] In one embodiment of the present invention, infrared light is irradiated multiple times to obtain one detection signal. Furthermore, by making each irradiation period the same and extremely short, the accuracy of distance information is improved. In addition, a first optical sensor that absorbs visible light and transmits infrared light, and a second optical sensor that absorbs infrared light The first optical sensor absorbs visible light first, and the second optical sensor mainly By absorbing infrared light, it is possible to miniaturize the pixels of semiconductor devices while enabling two-dimensional imaging and three-dimensional imaging. This allows simultaneous imaging of images.

[0023] One embodiment of the present invention disclosed in this specification is a photoelectric conversion element including a first photoelectric conversion element, a second photoelectric conversion element, a first A signal charge is stored in the first FD node based on the amount of visible light irradiated on the photoelectric conversion element. a first storage transistor for storing a second photoelectric conversion element and a second storage transistor for storing a second photoelectric conversion element based on the amount of infrared light irradiated thereto; a second storage transistor for storing the signal charge in a second FD node; and a signal for performing arithmetic processing based on the detection signals output from the first output line and the second output line. a processing circuit; and a driving method of a semiconductor device including the first photoelectric conversion element. A potential that sets the second FD node to a first high potential is supplied to one electrode of the second photoelectric conversion element. The infrared light is irradiated from the light source to the object to be detected for a period T. The infrared light reaches the object and is reflected. The light source stops irradiating the infrared light from the time when the infrared light starts to be incident on the second photoelectric conversion element. During the first period until the time when the second storage transistor is turned on, the potential of the gate electrode of at least the second storage transistor is set to the first potential. The high potential of 2 is repeated n times (n is a natural number of 2 or more), and after the nth first period A first detection signal based on a first potential difference between the potential of the second FD node and a low potential is output to a second output. After obtaining a first detection signal from the line of force, a first detection signal is applied to one electrode of the second photoelectric conversion element. A potential is supplied to the FD node 2 at a first high potential, and infrared light is emitted from the light source to the object to be detected. The infrared light is emitted for a period T, and the infrared light that reaches the object and is reflected from the time the light source stops emitting the infrared light is measured. The second period until the time when the incident infrared light to the second photoelectric conversion element is terminated is at least The potential of the gate electrode of the second storage transistor is set to the second high potential n times. a second potential difference between the potential of the second FD node and the low potential after the n-th second period, A detection signal of the second is obtained from the second output line, and the first A potential is supplied to make the FD node the third high potential, and the infrared light from the first irradiation is incident on the object to be detected. The time when the light reaches the first photoelectric conversion element and is reflected and starts to be incident on the second photoelectric conversion element The infrared light from the last irradiation reaches the object to be detected, is reflected, and is incident on the first photoelectric conversion element and During a third period until the time when the incidence of the first and second photoelectric conversion elements is terminated, at least the first accumulation The potential of the gate electrode of the multiplication transistor is set to a fourth high potential, and the first FD node after the third period A third detection signal based on a third potential difference between the potential of the first terminal and the low potential is obtained from the first output line. After obtaining the second detection signal, the speed of light is c, the first detection signal is S1, and the second detection signal is S 2, the signal processing circuit uses the following equation:

number

[0024] Another embodiment of the present invention disclosed in this specification is a first photoelectric conversion element, a second photoelectric conversion element, A first signal charge is generated based on the amount of visible light irradiated on the first photoelectric conversion element. a first storage transistor for storing the first signal charge in the first storage transistor; a first amplifying transistor for amplifying the first signal potential; A first output transistor outputs a detection signal from a first output line, and a second photoelectric conversion element receives the detection signal. A second accumulation circuit accumulates a second signal charge in a second FD node based on the amount of infrared light incident thereon. an amplifier transistor for amplifying a second signal potential converted based on an accumulated amount of the second signal charge; a second amplifying transistor, and a second output of the detection signal based on the amplified second signal potential; a plurality of pixels including a second output transistor outputting from the first output line and a second output transistor outputting from the first output line and the second output transistor; A signal processing circuit that performs arithmetic processing based on a detection signal output from the force line. A method for driving a device, comprising: A potential that sets the second FD node to a first high potential is supplied to the second FD node, and a voltage is applied from the light source to the object to be detected. Infrared light is irradiated for a period T, and the infrared light that reaches the object and is reflected is sent to the second photoelectric conversion element. The first period from the time when the light source starts to emit infrared light to the time when the light source stops emitting infrared light is The potential of the gate electrode of at least the second storage transistor is set to the second high potential. is a natural number equal to or greater than 2) times, and after repeating n times, the second FD after the nth first period The potential of the node is amplified by the second amplifier transistor, and the gate of the second output transistor is a potential that sets the second amplifier transistor and the second output transistor at a third high potential; The potential of the second output line is changed by conducting the second output transistor. A potential is supplied to the gate electrode of the second output line after the first low potential is supplied. A first potential difference between the first potential and the first low potential is output from the second output line, and after the output, A first detection signal is obtained based on the potential difference between the first and second photoelectric conversion elements. A potential is supplied to one electrode of the conversion element to set the second FD node to the first high potential, and The object is irradiated with infrared light for a period T, and the light source stops irradiating the infrared light. The time when the infrared light reflected from the object to be detected stops being incident on the second photoelectric conversion element During the second period at the second storage transistor, the potential of the gate electrode of at least the second storage transistor is set to a second high voltage. Repeat this process n times, and after repeating it n times, the second FD number after the nth second period is The potential of the input terminal is amplified by the second amplifier transistor, and the potential of the input terminal is input to the gate of the second output transistor. A potential is supplied to the electrode at a third high potential, and the second amplifying transistor and the second output transistor The potential of the second output line is changed by conducting the second output transistor A potential is supplied to the gate electrode of the second output line after the first low potential is supplied. A second potential difference between the potential and the first low potential is output from a second output line, and after the output, A second detection signal is obtained based on the potential difference, and a first A potential is supplied to make the FD node the fourth high potential, and the infrared light from the first irradiation is incident on the object to be detected. The time when the light reaches the first photoelectric conversion element and is reflected and starts to be incident on the second photoelectric conversion element The infrared light from the last irradiation reaches the object to be detected, is reflected, and is incident on the first photoelectric conversion element and During a third period until the time when the incidence of the first and second photoelectric conversion elements is terminated, at least the first accumulation The potential of the gate electrode of the multiplication transistor is set to a fifth high potential, and the first FD node after the third period The potential of the first output transistor is amplified by the first amplifier transistor, and the gate potential of the first output transistor is a sixth high potential is supplied to the first amplifying transistor and the first output transistor. The potential of the first output line is changed by conducting the first output transistor. A potential is supplied to the gate electrode to set it to a second low potential, and the voltage of the first output line after the second low potential is supplied is A third potential difference between the first low potential and the second low potential is output from the first output line. A third detection signal is obtained based on the phase difference. After obtaining the second detection signal, the speed of light is c, the first detection signal is When the detection signal of the first detection signal is S1 and the second detection signal is S2, the following equation is calculated by the signal processing circuit:

number

[0025] In the above, the plurality of pixels included in the semiconductor device are each a second photoelectric conversion element and a test object. It is preferable to calculate the distance to the exit.

[0026] In the above, the light source may be mounted inside the semiconductor device, or may be installed outside. It's fine if it is.

[0027] In the above, an irradiation control device may be mounted inside the semiconductor device. The device sets the period from the start to the end of infrared light irradiation and the number of infrared light irradiations, and Based on this, it is possible to output a pulse-shaped signal synchronized with the light source.

[0028] In this specification, the term "delay period" refers to the time period during which light is irradiated from the light source to the object to be detected. The time between the start time and the time when the light reflected from the object begins to enter the optical sensor. This refers to the difference. Effect of the Invention

[0029] By utilizing the delay period that occurs each time infrared light is irradiated, a detection signal can be acquired, enabling more accurate distance measurement. In addition, the reflected light from the same point on adjacent photodiodes can be obtained. By continuously detecting the distance, the accuracy of the distance information can be maintained even when the object is moving at high speed. In addition, by detecting visible light during the period when distance information is acquired, image information can be obtained at the same time as distance information. It can be obtained. [Brief description of the drawings]

[0030] [Figure 1] 1A to 1C are diagrams illustrating a semiconductor device. [Diagram 2] 1A and 1B are diagrams illustrating an optical sensor. [Diagram 3] 1A and 1B are diagrams illustrating an optical sensor. [Figure 4] 1A and 1B are diagrams illustrating an optical sensor. [Diagram 5] FIG. 4 is a diagram illustrating a timing chart of an optical sensor. [Figure 6] FIG. 2 illustrates a read circuit. [Figure 7] FIG. 4 is a diagram illustrating a timing chart of an optical sensor. [Figure 8] FIG. 4 is a diagram illustrating a timing chart of an optical sensor. [Figure 9] FIG. 13 is a diagram for explaining the ratio of a delay period. [Figure 10] FIG. 1 is a circuit diagram of a plurality of photosensors arranged in a matrix. [Figure 11] 1A and 1B are a top view and a cross-sectional view of an optical sensor. [Figure 12] FIG. [Figure 13] FIG. 2 is a diagram illustrating a plurality of optical sensors arranged in a matrix. [Figure 14] FIG. [Figure 15] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The embodiment will be described in detail with reference to the drawings. However, the present invention is not limited to the following description. The present invention is not limited to the above embodiment, and various changes and modifications may be made in the form and details without departing from the spirit and scope of the present invention. It will be easily understood by those skilled in the art that the above-mentioned invention can be obtained by the following embodiments. The present invention should not be construed as being limited to the contents described below. The same reference numerals are used in different drawings to indicate the same parts or parts having similar functions. A repeated explanation thereof will be omitted.

[0032] (Embodiment 1) The structure of a semiconductor device 500 according to one embodiment of the invention disclosed in this specification is shown in FIG. The semiconductor device 500 receives detection signals output from the optical sensors 100 (to be described later). The total distance of the detected object is calculated based on the distance between each optical sensor 100 and a point on the detected object. This is a device that acquires distance information about the body.

[0033] <Configuration of the semiconductor device 500> As shown in FIG. 1A, a semiconductor device 500 includes at least a plurality of semiconductor devices arranged in a matrix. The pixel 501 includes a light receiving section 502 and a signal processing circuit 503. The optical sensor 100 includes:

[0034] The light source 504 and the irradiation control device 505 may be mounted inside the semiconductor device 500. , may be installed externally.

[0035] As shown in FIG. 1B, infrared light 507 (irradiation) is emitted from a light source 504 to an object 506 to be detected. The light (reflected light 508) that is reflected by the object 506 is incident on the semiconductor device. The light is incident on each of the optical sensors 100 included in the device 500 .

[0036] The light receiving unit 502 detects the amount of light based on a pulse signal from the irradiation control device 505. The signal is output to the signal processing circuit 503.

[0037] The signal processing circuit 503 determines the amount of reflected light 508 and detects whether the infrared light is incident on the light receiving unit 504 or not. The time it takes for the light to reach the sensor 102 (delay period ΔT) is calculated, and the delay period ΔT is used to determine the time for each light sensor 102 to reach the sensor 102. The signal processing circuit 503 calculates the distance x between the point on the object to be detected and the object to be detected. For example, the information is output to a display device or the like (not shown).

[0038] The light source 504 irradiates the object to be detected with infrared light in response to a command from the irradiation control device 505. The infrared light irradiation is performed multiple times, and each irradiation period is the same and extremely short. It is preferable to do so.

[0039] It should be noted that visible light may be incident on the light receiving section 502 .

[0040] <Optical sensor configuration example 1> Next, a configuration of the optical sensor 100 included in the semiconductor device according to one embodiment of the invention disclosed in this specification will be described. An example of this will be described with reference to FIG. 2. FIG. 2 is a circuit diagram of the optical sensor 100. However, the optical sensor 100 is not limited to this configuration and may include at least one photodiode and one transistor. It is sufficient that the semiconductor device includes a transistor.

[0041] As shown in FIG. 2, the optical sensor 100 includes a photodiode 102, a transistor 103, The transistor 104 and the transistor 105 are included.

[0042] The optical sensor 100 shown in FIG. 2 is composed of three transistors and one photodiode. By reducing the number of elements in the optical sensor 100, the pixels can be miniaturized, and the semiconductor device can be manufactured. It becomes easier to miniaturize.

[0043] In FIG. 2, the signal line 11 is a reset signal line (PR), and the signal line 12 is a charge storage signal line (T X), signal line 13 is a selection signal line (SE), node 14 is a floating diffusion A signal line 15 is a photosensor reference signal line, and a signal line 16 is a photosensor output signal line. This is Line No.

[0044] In this specification, the photodiode 102 is irradiated with at least infrared light. do.

[0045] The photodiode 102 is a photoelectric conversion element that detects light incident on the diode and generates an electric charge. It functions as a conversion element. The amount of charge generated is determined based on the amount of incident light.

[0046] The transistor 103 functions as a transistor for controlling imaging. A transistor that controls the amount of charge stored in node 14 based on the amount of light irradiated on node 102. It functions as a dialyzer.

[0047] As shown in FIG. 2, in the optical sensor 100, one electrode of the photodiode 102 is a signal The other electrode of the photodiode 102 is electrically connected to the line 11. The transistor 10 is electrically connected to one of the source electrode and the drain electrode of the transistor 10. The other of the source electrode or drain electrode of the transistor 103, the gate electrode of the transistor 104, and the node The source electrode or drain electrode of the transistor 104 is electrically connected to the transistor 14. One of the electrodes is electrically connected to the signal line 15. One of the drain electrodes is electrically connected to the signal line 16. the other of the source electrode or drain electrode of the transistor 105 The gate electrode of the transistor 103 is electrically connected to the other electrode of the signal line 1. 2 is electrically connected, and the gate electrode of the transistor 105 is electrically connected to the signal line 13. This is being continued.

[0048] In FIG. 2, the anode of the photodiode 102 is electrically connected to the signal line 11. The cathode of the diode 102 is connected to one of the source electrode and the drain electrode of the transistor 103. Although the photodiode 102 is electrically connected, the present invention is not limited to this. The cathode is electrically connected to the signal line 11, and the anode of the photodiode 102 is connected to the transistor 1 It may be electrically connected to either the source electrode or the drain electrode of 03.

[0049] <Optical sensor configuration example 2> In addition, in a semiconductor device according to one embodiment of the invention disclosed in this specification, the optical sensor 100 has a length of m Even if they are arranged in a matrix of n (rows) by n (columns) (m and n are natural numbers greater than or equal to 2), In FIG. 3, as an example, the optical sensors adjacent in the column direction are optical sensors 100(k-1)( The optical sensor 100(k) is represented as k being a natural number of 2 or more and n or less.

[0050] The optical sensor 100(k-1) includes a photodiode 102(k-1) and a transistor 103. (k-1), transistor 104(k-1), and transistor 105(k-1), The sensor 100(k) includes a photodiode 102(k), a transistor 103(k), and a It has a transistor 104(k) and a transistor 105(k).

[0051] <Optical sensor configuration example 3> In addition, in a semiconductor device according to an embodiment of the invention disclosed in the specification, the optical sensor is an optical sensor 1. Each pixel includes one optical sensor 100A and one optical sensor 100B. In the semiconductor device 500, the object to be detected is determined based on the detection signal output from each optical sensor 100A. Image information of the entire product is acquired, and simultaneously with the acquisition of the image information, the image information is output from each optical sensor 100B. The distance between each optical sensor 100B and a point on the object to be detected is calculated based on the detected signal. This makes it possible to obtain distance information for the entire detected object.

[0052] As shown in FIG. 1C, a light source 504 emits infrared light 507 and a photodetector 508 toward an object 506 to be detected. The visible light 517 is irradiated to the object to be detected 506, and the light that is reflected upon reaching the object to be detected (reflected light) is The light is incident on each of the optical sensors 100A and 100B included in the optical sensor 500. The sensor 100A absorbs visible light 518 from the reflected light, and the optical sensor 100B absorbs infrared light. The reflected light 508 (also referred to as infrared reflected light) is absorbed.

[0053] In this specification, the photodiode 102A is a diode that receives light in a specific wavelength range, for example. It absorbs visible light and transmits light other than a specific wavelength range, for example infrared light. The photodiode 102B absorbs light in a specific wavelength range, for example visible light, and It is assumed that the material also absorbs light outside the wavelength region, for example infrared light.

[0054] The signal processing circuit 503 determines the amount of infrared reflected light absorbed by each optical sensor 100B, and The time it takes for light to reach the light receiving unit 502 from the light source 504 (delay period ΔT) is calculated, and the delay period Using ΔT, the distance x between each optical sensor 100B and a point on the object to be detected is calculated. Signal processing The calculation result of the circuit 503 is outputted to, for example, a display device (not shown).

[0055] In addition, the optical sensor 100A and the optical sensor 100B are overlapped in the light receiving section 502. Visible light 518 reflected from 506 is first substantially absorbed by optical sensor 100A.

[0056] 1 is a diagram showing an example of a configuration of an optical sensor group including one optical sensor 100A and one optical sensor 100B. This will be described with reference to FIG. 4. FIG. 4 is a circuit diagram of the optical sensor group 110. The optical sensor group 110 includes one optical sensor 100A and one optical sensor 100B. Not limited to, at least a photodiode that transmits infrared light and absorbs visible light, and a The photodiode absorbs the visible light and accumulates the signal charge in the FD node based on the amount of visible light. A transistor and a transistor that accumulates signal charge in the FD node based on the amount of infrared light. It is sufficient that the above is included.

[0057] As shown in FIG. 4, the optical sensor group 110 includes two photodiodes and six transistors. In this specification, a photosensor that absorbs visible light and transmits infrared light is particularly In this case, the optical sensor 100A, the photodiode 102A, the transistor 103A, The transistor 104A and the transistor 105A are optical sensors that specifically absorb infrared light. In this case, the optical sensor 100B, the photodiode 102B, the transistor 103B, They will be represented as transistor 104B, transistor 105B, and so on.

[0058] The optical sensor 100A and the optical sensor 100B shown in FIG. The elements of the optical sensor 100A and the optical sensor 100B are each composed of a photodiode. By reducing the number of elements compared to the number of elements in a typical optical sensor, pixels can be made smaller. This makes it easier to miniaturize the semiconductor device.

[0059] In FIG. 4, signal lines 11A and 11B are reset signal lines (PR), and signal lines 12A and 12B are is a charge storage signal line (TX), signal lines 13A and 13B are selection signal lines (SE), and node 14A , 14B is a floating diffusion (FD) node, and a signal line 15 is a photosensor. The reference signal line, signal lines 16A and 16B are optical sensor output signal lines. The signal lines used for 2D imaging are represented by _2, and the signal lines used for 3D imaging are represented by _3. is.

[0060] Photodiodes 102A and 102B detect light incident on them and generate an electric charge. It functions as a photoelectric conversion element that generates an electric charge. The amount of electric charge generated is determined according to the amount of light irradiated. .

[0061] The transistors 103A and 103B function as transistors for controlling imaging. Based on the amount of light irradiated to the photodiodes 102A and 102B, the node 14A and the node It functions as a transistor that controls the amount of charge stored in 14B.

[0062] As shown in FIG. 4, in the optical sensor group 110, the photodiodes 102A and 10 The anodes of the photodiodes 11A and 11B are electrically connected to the signal lines 11A and 11B, respectively. The cathodes of transistors 102A and 102B are connected to the source or drain electrodes of transistors 103A and 103B. The transistors 103A and 103B are electrically connected to one of the electrodes. The other of the source electrode or drain electrode and the gate electrode of the transistors 104A and 104B are connected to each other. Each of the transistors is electrically connected to the nodes 14A and 14B. Either the source electrode or the drain electrode of the capacitors 104A and 104B is electrically connected to the signal line 15. One of the source electrodes or drain electrodes of the transistors 105A and 105B is connected to The transistor 104A is electrically connected to the signal lines 16A and 16B. , 104B and the other of the source electrodes or drain electrodes of the transistors 105A, The other of the source electrode and drain electrode of 105B is electrically connected to the other of the source electrode and drain electrode of 105B. The gate electrodes of the transistors 103A and 103B and the signal lines 12A and 12B are The gate electrodes of the transistors 105A and 105B are electrically connected to the signal lines 13A and 13B. B are electrically connected to each other.

[0063] <Mechanism of imaging> Here, the mechanism of imaging will be described. In the following, the optical sensor 100 will be used as an example. However, a similar mechanism is also applied to the optical sensors 100A and 100B. The potential of the anode of the photodiode 102 is changed from "L" to "H", and the gate of the transistor 103 When the potential of the positive electrode is changed from "L" to "H", a positive charge is accumulated in the node 14. In this state, when the potential of the signal line 11 is changed from "H" to "L", Negative charges are accumulated in the node 14 based on the amount of light irradiated (image capture begins). When the potential of the gate electrode of the transistor 103 is changed from "H" to "L", the potential at the node 14 The charge accumulation stops (image capture ends). The potential of the gate electrode of the transistor 103 is switched. By this, the amount of charge stored in the node 14 can be controlled.

[0064] The semiconductor layer used in the transistor 103 may be made of amorphous silicon or microcrystalline silicon. It is preferable to use an oxide semiconductor as the semiconductor layer. Since the off-state current of the phototransistor is extremely low, the photodiode 102 is illuminated with light. Therefore, the generated electric charge can be stored for a long time. Since it is possible to hold the image, accurate imaging data can be easily obtained.

[0065] In addition, when an oxide semiconductor material is used for the semiconductor layer of the transistor 103, Therefore, it is possible to suppress the flow of electric charges leaking to the photodiode 102. If charge is stored in the node 14 for a long time, the effect of leakage charge becomes large, and the oxidation It is particularly preferable to use an oxide semiconductor for the semiconductor layer. By detecting with high accuracy and obtaining a highly reliable detection signal, the performance of the entire optical sensor 100 is improved. It will also be possible to increase

[0066] The transistor 104 amplifies the converted potential based on the amount of charge stored at the node 14. By increasing the amplification factor of the transistor 104, the optical sensor 1 It can increase the sensitivity of 00.

[0067] The semiconductor layer used for the transistor 104 may be polycrystalline silicon, single crystal silicon, or the like. By using these materials for the semiconductor layer, By increasing the amplification rate of electric charges, a more sensitive amplification transistor can be constructed. It becomes possible to do so.

[0068] The transistor 105 functions as a transistor that controls the output of the optical sensor 100 . That is, the potential amplified by the transistor 104 is changed by switching the potential of the gate electrode. Then, the potential can be output as the potential of the signal line 16.

[0069] The semiconductor layer used for the transistor 105 may be polycrystalline silicon, single crystal silicon, or the like. It is preferable to use any of these materials. Therefore, the output period of the detection signal can be shortened, and the optical sensor 10 0 output can be controlled at high speed. In addition, by using these materials for the semiconductor layer, This makes it possible to control the switching speed of the signal line 16 over a wider range. By increasing the freedom of speed and clearly extracting speed differences, it is possible to obtain more accurate detection signals. become.

[0070] As described above, the optical sensor 100 has four elements: one photodiode and three transistors. Since it is possible to configure the optical sensor with a small number of elements, This makes it easier to integrate the pixels at a high density and achieve miniaturization of the pixels. The semiconductor layer of the transistor 105 is made of a material such as polycrystalline silicon or single crystal silicon. The semiconductor layer of the transistor 103 is made of amorphous silicon, microcrystalline silicon, or By using oxide semiconductor materials to form a stacked structure, pixels can be made smaller. can.

[0071] The charge generated by irradiating the photodiode 102 with light is stored in the node 14. In cases where it is important to accumulate the signal in a short time, i.e., when the object to be detected is moving at high speed, For example, the semiconductor layer used in the transistor 103 may be amorphous silicon or polycrystalline silicon. Materials such as silicon and single crystal silicon can also be used. The time that the charge is stored in the node 14 is short, so the adverse effects caused by leakage charge are can be suppressed.

[0072] In addition, in order to obtain a small-to-medium-sized optical sensor 100 that places special importance on high-speed operation, All transistors (transistor 103, transistor 104, transistor 105) It may also be made of polycrystalline silicon, single crystal silicon, or other materials.

[0073] In addition, when emphasis is placed on low cost, large size, and high performance, all the transistors that make up the pixels The transistors (transistor 103, transistor 104, transistor 105) are oxidized It may also be constructed from semiconductor materials.

[0074] In addition, when cost reduction and large size are important, all the transistors constituting the pixel are (Transistor 103, Transistor 104, Transistor 105) are made of amorphous silicon. It can also be made of silicon or microcrystalline silicon.

[0075] <Method 1 of Driving a Semiconductor Device> An example of a method for driving a semiconductor device having the optical sensor 100 shown in FIG. 2 will be described below. By using this driving method, two different detection signals are obtained, and the semiconductor device and the object to be detected are The distance to an object can be calculated.

[0076] The distance is calculated by a signal processing circuit included in the semiconductor device. It is possible to carry out appropriate calculations based on the different detection signals obtained. The distance between the optical sensor and a point on the object to be detected is determined by the irradiation of infrared light from the light source to the object to be detected. It is possible to calculate it by repeating the above process and stopping multiple times.

[0077] Furthermore, by shortening the period from the start to the end of infrared light irradiation and repeating it multiple times, The conductor device can obtain the distance between the object to be detected and the optical sensor with high accuracy.

[0078] First, the timing chart will be described.

[0079] FIG. 5 shows a pulse 30 indicating the timing at which infrared light is irradiated from the light source to the object to be detected. 1. A phase that indicates the timing at which light that reaches the object being detected and is reflected enters the photodiode. pulse 302, pulse (PR) on signal line 11, pulse (TX) on signal line 12, pulse (TX) on signal line 13 A pulse (SE), a pulse (FD) at node 14, and a pulse on signal line 16 are shown.

[0080] In this specification, the pulse 301 indicates the period during which infrared light is irradiated by "H" and the red The period when no external light is irradiated is represented by "L".

[0081] As shown in FIG. 5, infrared light irradiation is performed multiple times for a period T. Note that the first infrared light irradiation The first infrared light irradiation is from time T2 to time T4, the second infrared light irradiation is from time T6 to time T8, and the third infrared light irradiation is from time T9 to time T10. The first infrared light irradiation is from time T12 to time T15, and the fourth infrared light irradiation is from time T18 to time T16. It is time T20, and the period T is extremely short.

[0082] In the present specification, the pulse 302 is an infrared light irradiated from a light source to an object to be detected. The period during which the light is reflected by the object and enters the optical sensor 100 is represented by "H", and the period during which the light is not entering the optical sensor is represented by "H". The period when the signal is short is represented by "L".

[0083] In the pulse (PR) of the signal line 11, the potential supplied to the anode of the photodiode 102 is high. The period of high potential is represented by "H" and the period of low potential is represented by "L". Signal line 11_(k-1) (PR_(k-1)), signal line 11_(k) (PR_(k)) The same applies to the signal line 11A (PR_2) and the signal line 11B (PR_3) in FIG.

[0084] In this specification, a pulse (TX) on the signal line 12 applies a current to the gate electrode of the transistor 103. The period when the supplied potential is high is represented by "H", and the period when the potential is low is represented by "L". In FIG. 7, the signal line 12_(k-1) (TX_(k-1)) and the signal line 12_(k ) (TX_(k)), signal line 12A (TX_2) and signal line 12B (TX_3) in FIG. ) is also the same.

[0085] In this specification, a pulse (SE) on the signal line 13 applies a voltage to the gate electrode of the transistor 105. The period when the supplied potential is high is represented by "H", and the period when the potential is low is represented by "L". In FIG. 7, the signal line 13_(k-1) (SE_(k-1)) and the signal line 13_(k ) (SE_(k)), signal line 13A (SE_2) and signal line 13B (SE_3) in FIG. ) is also the same.

[0086] In the pulse (FD) of node 14 shown in FIG. 5, the high potential period is represented by “H” and the low potential period is represented by “L”. The potential difference between the low potential "L" at time T9 and the node 14 is "V1" at time T The potential difference between the low potential "L" at 21 and node 14 is represented as "V2."

[0087] In the pulse of the signal line 16 shown in FIG. 5, the high potential period is represented by "H" and the low potential period is represented by "L". At time T11, the potential difference between the low potential "L" and the signal line 16 is "V S1 " At time T2 The potential difference between the low potential "L" at 4 and the signal line 16 is "V S2 " is used to represent this.

[0088] In FIG. 5, the potential difference between the low potential “L” and the signal line 16 at time T11 is “V S 1” corresponds to the first detection signal S1, and the potential between the low potential “L” and the signal line 16 at time T24 The potential difference "V S2 " corresponds to the second detection signal S2.

[0089] In FIG. 5, the delay period ΔT is from time T2 to time T3, from time T6 to time T7, This corresponds to time T12 to time T13 and time T18 to time T19.

[0090] In this specification, the low potential "L" refers to a common potential.

[0091] In FIG. 5, the period T is fixed for the four infrared light irradiations.

[0092] Furthermore, during the period in which the image is captured, the distance from the semiconductor device to the object to be detected does not change. Therefore, the delay period ΔT can be assumed to be equal for the four infrared light irradiations.

[0093] In FIG. 5, as an example, infrared light for acquiring the first detection signal and the second detection signal is used. Irradiation was performed twice for each treatment, but it is also effective to perform it three or more times, and the number of times is not particularly limited. However, the number of infrared light irradiations to obtain the first detection signal and the number of infrared light irradiations to obtain the second detection signal are not limited. The number of infrared light irradiations for obtaining the same value is set to be equal.

[0094] Next, the distance between a certain optical sensor of the semiconductor device and a certain point on the object to be detected is calculated. The method is explained below. When infrared light is irradiated twice according to the timing chart in FIG. Let the distance from the semiconductor device to the object to be detected be x, and the detection signal strength be the net exposure time ( The proportional constant is α (where α is the incident time of the reflected light during the imaging period). constant), the first detection signal is S1(2), the second detection signal is S2(2), and the speed of light is c(3×1 0 8 m / s), the first detection signal S1(2), the second detection signal S2(2), the delay period The interval ΔT and distance x can be expressed as follows:

number

[0095] By analogy with the case where infrared light is irradiated twice, the following can be said about the case where infrared light is irradiated n times: That is, the distance from the semiconductor device to the object to be detected is x, and the detection signal is If the signal intensity is proportional to the net exposure time (the time during which the reflected light is incident during the imaging period), then The proportionality constant is α, the first detection signal is S1(n), the second detection signal is S2(n), and the speed of light is c( 3×10 8 m / s), the first detection signal S1(n), the second detection signal S2(n), The delay period ΔT and the distance x can be expressed as follows:

number

[0096] From the above calculation, even if the number of infrared light irradiations is different, the distance x does not depend on the delay period ΔT. It can be seen that this can be calculated from the projection period, detection signal, and speed of light.

[0097] The first detection signal S1(n) and the second detection signal S2(n) are respectively generated when the number of infrared light irradiations is n. The larger the value, the higher the accuracy. The more times the infrared light is irradiated, the smaller the change in the potential of the FD node. The change in potential in the output signal line increases, and the change in intensity of the detection signal increases. This is because the S / N ratio can be improved by increasing the number of infrared light irradiations. The higher the accuracy, the more accurately the distance x can be calculated.

[0098] In addition, the period T during which infrared light is irradiated must be set short enough to be at least equal to the delay period ΔT. It is preferable that the shorter the period T is, the larger the proportion of the delay period ΔT in the period T can be. By increasing the change in the first detection signal S1 and the second detection signal S2 with respect to the distance x, This makes it easier to increase the sensitivity to the distance x, and improves the accuracy.

[0099] That is, each time a detection signal is obtained, infrared light irradiation is repeated several times for an extremely short period T. This means that the semiconductor device and the object to be detected can be detected with high accuracy compared to irradiating infrared light once over a long period of time. This makes it possible to calculate the distance between the target point and the target point, and also greatly reduces the overall measurement time.

[0100] Next, a specific method for driving the semiconductor device will be described with reference to the timing chart shown in FIG. He explains.

[0101] At time T1, the potential of the signal line 11 is changed from "L" to "H" (first reset operation). Furthermore, the potential of the signal line 12 is changed from "L" to "H". At this time, the photodiode 102 The transistor 103 is turned on, and the potential of the node 14 becomes "H".

[0102] At time T2, the first irradiation of infrared light from the light source to the object to be detected begins. Pulse In 301, the potential of the signal line 11 is changed from "L" to "H". The potential of the signal line 12 is maintained at "H".

[0103] At time T3, imaging for the first infrared light irradiation is started. The reflected light from the object to be detected due to the first infrared light irradiation starts to enter the photodiode 102. The reflected light is infrared light. The pulse 302 is indicated by "L" to "H". The potential of the node 14 starts to drop from "H". The signal line 12 maintains "H".

[0104] At time T4, the first infrared light irradiation is stopped. (From time T2 to time T4 is the period T.)

[0105] In the pulse 301, it is shown as "H" to "L". Then, the signal is set to "L". The first infrared light irradiation ends. Also, at time T4, As a result, the potential of the node 14 stops decreasing and becomes constant.

[0106] The potential of the node 14 at time T4 is the potential of the node 14 during the period from time T3 to time T4 (the first infrared The amount of light irradiated onto the photodiode 102 during the period of light irradiation is determined based on the amount of light irradiated onto the photodiode 102 during the period of light irradiation. In other words, the greater the light intensity is, the greater the potential change will be for the same irradiation period. If the irradiation period is longer, the potential change will be greater.

[0107] When the signal line 12 is set to "L", the parasitic capacitance between the signal line 12 and the node 14 is This causes a change in the potential of the node 14. If the change in potential is large, the photodiode 102 Therefore, it is difficult to accurately obtain the photocurrent generated by the parasitic capacitance. Therefore, the capacitance between the gate electrode and the source electrode of the transistor 103 or the capacitance between the gate electrode and the source electrode of the transistor 103 1. Reducing the capacitance between the gate electrode and the drain electrode of the transistor 11, connecting a storage capacitor to the node 14, etc. The above measures are effective. In the photosensor of this embodiment, these measures are taken to prevent the parasitic capacitance from It is assumed that the change in potential of the node due to the above can be ignored.

[0108] At time T5, the incidence of reflected light from the object to the photodiode 102 ends. The pulse 302 is shown as going from "H" to "L".

[0109] At time T6, the second irradiation of the object with infrared light from the light source is started. In 301, the potential of the signal line 12 is changed from "L" to "H". The potential of the node 14 is maintained at the potential at time T4.

[0110] At time T7, imaging for the second infrared light irradiation is started. The reflected light from the object to be detected due to the second infrared light irradiation starts to enter the photodiode 102. In the pulse 302, the potential of the node 14 changes from "L" to "H". The potential at signal line 4 starts to decrease. The signal line 12 remains at “H”.

[0111] At time T8, the second infrared light irradiation is stopped. (From time T6 to time T8 is the period T.)

[0112] In the pulse 301, it is shown as "H" to "L". Then, the second infrared light irradiation is completed. Also, at time T8, The potential of node 14 at time T8 stops decreasing and becomes constant. Let this be “V1”.

[0113] The potential "V1" of the node 14 at time T8 is the potential "V1" of the photodiode 14 during the period from time T3 to time T4. The amount of light irradiated to the diode 102 and the amount of infrared light irradiated from time T7 to time T8 (the second infrared light The amount of light incident on the photodiode 102 during the period of illumination is determined based on the total amount of light incident on the photodiode 102 during the period of illumination.

[0114] At time T9, the incidence of reflected light from the object to the photodiode 102 ends. The pulse 302 is shown as going from "H" to "L".

[0115] At time T10, the potential of the signal line 13 is changed from "L" to "H" (first read start A potential "H" is supplied to the gate electrode, and the transistor 105 is turned on. The signal line 15 and the signal line 16 are brought into conduction through the transistors 104 and 105 .

[0116] The potential of the signal line 16 starts to drop from "H".

[0117] Before time T10, the signal line 16 is precharged. The potential is set to "H".

[0118] At time T11, the potential of the signal line 13 is changed from "H" to "L" (first readout end). The transistor 105 is cut off, and the potential of the signal line 16 stops decreasing and becomes constant. The potential of the signal line 16 at time T11 is expressed as "V S1 "

[0119] The potential of the signal line 16 at time T11 “V S1 " by obtaining the first infrared illumination The amount of light irradiated onto the photodiode 102 during the first irradiation and the amount of light irradiated onto the photodiode 102 during the second irradiation are The total amount of light incident on the diode 102 can be detected.

[0120] If the amount of light irradiated to the photodiode 102 is large, the number of nodes 14 in a certain period of time may decrease. Since the potential change is large, the potential of the node 14 is lowered. Since the channel resistance becomes higher, the rate at which the potential of the signal line 16 decreases becomes slower. The potential change of the signal line 14 and the potential change of the signal line 16 are inverted.

[0121] In addition, when the light intensity in the first and second infrared light irradiations is constant, the signal Electric potential of line 16 “V S1 " is proportional to the irradiation period.

[0122] At time T12, the third irradiation of infrared light from the light source to the object to be detected is started. In the example shown in FIG. 301, the numbers are indicated by "L" through "H."

[0123] At time T13, the reflected light from the object due to the third infrared light irradiation is detected by the photodiode. The light starts to enter the node 102. The pulse 302 is indicated by a change from "L" to "H."

[0124] At time T14, the potential of the signal line 11 is changed from "L" to "H" (second reset operation Furthermore, the potential of the signal line 12 is changed from "L" to "H." At this time, the photodiode 10 2 and the transistor 103 are turned on, and the potential of the node 14 becomes "H."

[0125] The second reset operation may be performed before the third irradiation of infrared light.

[0126] At time T15, imaging for the third infrared light irradiation is started. Then, the third infrared light irradiation is stopped. (The period from time T12 to time T15 is called period T.) The pulse 301 is shown as "H" to "L". The potential of the node 14 starts to drop from "H". The signal line 12 is Maintain H”.

[0127] At time T16, the reflected light from the object to the photodiode 102 stops being incident. The pulse 302 is shown as going from "H" to "L". The signal line 12 is at potential "H". Maintain.

[0128] The third infrared light irradiation imaging is completed. Also, at time T16, node 14 The potential stops decreasing and becomes constant.

[0129] The potential of the node 14 at time T16 is the same as that of the node 14 during the period from time T15 to time T16 (the third period). The amount of light irradiated onto the photodiode 102 after the infrared light irradiation is determined based on the amount of light irradiated onto the photodiode 102 after the infrared light irradiation.

[0130] At time T17, the potential of the signal line 12 is changed from "H" to "L".

[0131] In addition, the photodiode 102 is not irradiated with reflected light during the period from time T16 to time T17. I can't.

[0132] At time T18, the fourth irradiation of infrared light from the light source to the object to be detected is started. In the example shown in FIG. 301, the numbers are indicated by "L" through "H."

[0133] At time T19, the reflected light from the object due to the fourth infrared light irradiation is detected by the photodiode. The light starts to enter the node 102. The pulse 302 is indicated by a change from "L" to "H."

[0134] At time T20, imaging for the fourth infrared light irradiation is started. Then, the fourth infrared light irradiation is stopped. (The period from time T18 to time T20 is called period T.) The pulse 301 is shown as a change from "H" to "L". At time T20, the potential of node 14 is changed from "L" to "H". The potential starts to decrease from

[0135] At time T21, the reflected light from the object to the photodiode 102 stops being incident. The pulse 302 is shown as going from "H" to "L". The signal line 12 is at potential "H". Maintain.

[0136] At time T21, the imaging for the fourth infrared light irradiation ends. At time T21, the potential of node 14 stops decreasing and becomes constant. The potential of 4 is “V2”.

[0137] The potential "V2" of the node 14 at time T21 is The amount of light irradiated onto the photodiode 102 and the amount of light The amount of light incident on the diode 102 is determined based on the total amount of light.

[0138] At time T22, the potential of the signal line 12 is changed from "H" to "L".

[0139] At time T23, the potential of the signal line 13 is changed from "L" to "H" (start of second readout). A potential "H" is supplied to the gate electrode, and the transistor 105 is turned on. The signal line 15 and the signal line 16 are brought into conduction through the transistors 104 and 105 .

[0140] The potential of the signal line 16 starts to drop from "H".

[0141] Before time T23, the signal line 16 is precharged. The potential is set to "H".

[0142] The configuration of the read circuit that performs the precharge operation on the signal line 16 is not particularly limited. As shown in FIG. 1, the read circuit 101 can be configured with one Pch transistor 106. Signal line 17 is a precharge signal line. Node 18 is a high potential supply line. The gate electrode of the transistor 106 is electrically connected to the signal line 17. One of the source electrode or drain electrode of the transistor 106 is electrically connected to the signal line 16. The other of the source electrode or the drain electrode of the transistor 106 is electrically connected to the node 18. There are.

[0143] At time T24, the potential of the signal line 13 is changed from "H" to "L" (end of second readout). The transistor 105 is cut off, and the potential of the signal line 16 stops decreasing and becomes constant. The potential of the signal line 16 at time T24 is expressed as "V S2 "

[0144] The potential of the signal line 16 at time T24 “V S2 " is the third time that the Infrared Illumination The amount of light irradiated to the photodiode 102 after the fourth infrared light irradiation is The total amount of light incident on the diode 102 can be detected.

[0145] In addition, when the light intensity is constant in the third and fourth infrared light irradiations, the signal Electric potential of line 16 “V S2 " is proportional to the irradiation period.

[0146] In this embodiment, the imaging period ( Compared to time T3 to time T4 and time T7 to time T8), the third and fourth red Imaging period for external light irradiation (time T15 to time T16 and time T20 to time T21) Therefore, the potential of the signal line 16 at time T24 (V S2 )teeth, The potential of the signal line 16 at time T11 (V S1 ) is smaller than

[0147] At time T25, the optical sensor 100 outputs the first detection signal S1 and the second detection signal S2. can be obtained.

[0148] By applying the above-mentioned driving method to a plurality of pixels of a semiconductor device, The distance between the optical sensor and the object to be detected can be calculated more accurately.

[0149] <Method of Driving Semiconductor Device 2> An example of a method for driving the semiconductor device having the photosensor shown in FIG. 3 will be described with reference to FIG. do.

[0150] As shown in FIG. 7, infrared light irradiation is performed multiple times for a period T. Note that the first infrared light irradiation The first infrared light irradiation is from time T2 to time T5, and the second infrared light irradiation is from time T8 to time T10. The period T is extremely short.

[0151] In the pulse (FD) of node 14 in FIG. 7, the high potential period is “H” and the low potential period is “F”. At time T10, the potential difference between the low potential "L" and node 14_(k-1) is V1”, the potential difference between the low potential “L” and the node 14_(k) at time T11 is “V2”. It is represented as follows.

[0152] In the pulse of the signal line 16 in FIG. 7, the period of high potential is represented as "H" and the period of low potential is represented as "L". The potential difference between the low potential "L" and the signal line 16_(k-1) at time T14 is "V S1 " The potential difference between the low potential "L" and the signal line 16_(k) at time T15 is "V S2 "in, It represents.

[0153] In FIG. 7, the voltage between the low potential “L” and the signal line 16_(k−1) at time T14 Potential difference “V” S1 The low potential "L" at time T15 corresponds to the first detection signal S1, and the low potential "L" at time T15 corresponds to the first detection signal S2. 6_(k) and the potential difference between them is V S2 " corresponds to the second detection signal S2.

[0154] In addition, in FIG. 7, the delay period ΔT is from time T2 to time T3 and from time T8 to time T9. Equivalent.

[0155] In FIG. 7, the period T is fixed in the two infrared light irradiations.

[0156] During the imaging period, the distance from the light source to the object to be detected changes. It can be assumed that ΔT is approximately equal for the two infrared light irradiations.

[0157] In FIG. 7, as an example, infrared light for acquiring the first detection signal and the second detection signal is used. Although irradiation is performed twice, it is also effective to perform it three or more times, and the number of times is not particularly limited.

[0158] Next, the distance between a certain optical sensor of the semiconductor device and a certain point on the object to be detected is calculated. The method is explained below. When infrared light is irradiated twice according to the timing chart in FIG. Let the distance from the light source to the object be x, and the detected signal strength be the net exposure time (imaging period). The proportional constant is α (where α is constant). , the first detection signal is S1(2), the second detection signal is S2(2), and the speed of light is c(3×10 8 m / s), the first detection signal S1(2), the second detection signal S2(2), and the delay period ΔT , and distance x can be expressed as follows:

number

[0159] By analogy with the case where infrared light is irradiated twice, the capacity can be calculated by irradiating infrared light n times. The details are the same as those described above in the semiconductor device driving method 1, so they are omitted here. do.

[0160] Next, a specific method for driving the semiconductor device will be described with reference to the timing chart shown in FIG. He explains.

[0161] At time T1, the potential of the signal line 11_(k-1) is changed from "L" to "H" (reset Furthermore, the potential of the signal line 12_(k-1) is changed from "L" to "H". The diode 102_(k-1) and the transistor 103_(k-1) are conductive, and the node The potential of 14_(k-1) becomes “H”.

[0162] At time T2, the first irradiation of infrared light from the light source to the object to be detected begins. Pulse In 301, the potential of the signal line 11_(k-1) is indicated by "L" to "H". The potential of the signal line 12_(k-1) is kept at "H".

[0163] At time T3, the first image capture for the first infrared light irradiation is started. The reflected light from the object to be detected by the first infrared light irradiation is detected by the photodiode 102_( k-1). The reflected light is infrared light. In pulse 302, "L The potential of node 14_(k-1) starts to decrease from "H". The signal line 12_(k-1) remains at "H".

[0164] At time T4, the potential of the signal line 11_(k) is changed from "L" to "H" (reset operation Furthermore, the potential of the signal line 12_(k) is changed from "L" to "H". The node 102_(k) and the transistor 103_(k) are conductive, and the voltage at the node 14_(k) The digit is “H”.

[0165] At time T5, the first infrared light irradiation is stopped. (From time T2 to time T5 The period T is the period during which the signal line 1 goes from "H" to "L". The potential of 2_(k-1) is changed from "H" to "L". The first time for the first infrared light irradiation At time T5, the potential of node 14_(k-1) stops decreasing. and becomes constant.

[0166] Furthermore, at time T5, a second image capture for the first infrared light irradiation is started. In the first infrared light irradiation, the reflected light from the object to be detected is detected by the photodiode 10. The potential of the signal line 11_(k) is changed from "H" to "L". The potential of the line 12_(k) is maintained at "H". The potential of the node 14_(k) is changed from "H" to "L". Start to lower.

[0167] The potential of the node 14_(k-1) at time T5 is the potential between time T3 and time T5 (the first Based on the amount of light irradiated onto the photodiode 102_(k-1) during the first infrared light irradiation, The greater the amount of light, the greater the change in potential. The greater the light intensity, or the longer the irradiation period, the greater the change in potential, assuming the same intensity.

[0168] At time T6, the reflected light from the object to the photodiode 102_(k-1) The second imaging for the first infrared light irradiation is completed. Pulse 302 In this example, the potential of the signal line 12_(k) is changed from "H" to "L". In addition, the potential of the node 14_(k) stops decreasing and becomes constant.

[0169] At time T7, the potential of the signal line 12_(k) is changed from "H" to "L".

[0170] At time T8, the second irradiation of the object with infrared light from the light source is started. Pulse In 301, the potential of the signal line 12_(k-1) is changed from "L" to "H". The potential of the node 14_(k-1) is changed from L” to H. The potential of the node 14_(k-1) is maintained at the potential at time T5. do.

[0171] At time T9, the first image capture for the second infrared light irradiation is started. The reflected light from the object to be detected by the second infrared light irradiation is detected by the photodiode 102_( k-1) starts to enter the node 1. In pulse 302, it is shown as "L" to "H". The potential of the signal line 12_(k-1) starts to decrease from the potential at time T5. 1) maintains "H".

[0172] At time T10, the second infrared light irradiation is stopped. (From time T8 to time T10 The period between these two is called period T.)

[0173] In the pulse 301, the change from "H" to "L" is shown. The level is changed from "H" to "L". The first image capture for the second infrared light irradiation is completed. At time T10, the potential at node 14_(k-1) stops decreasing and becomes constant. The potential of the node 14_(k-1) at time T10 is set to "V1."

[0174] The potential "V1" of the node 14_(k-1) at time T10 is the potential "V1" of the node 14_(k-1) from time T3 to time T5. The amount of light irradiated onto the photodiode 102_(k-1) during the period from time T9 to time T1 Based on the total amount of light irradiated to the photodiode 102_(k-1) between It is decided.

[0175] Furthermore, at time T10, a second image capture is started in response to the second infrared light irradiation. The potential of the line 12_(k) is changed from "L" to "H". At time T10, the second infrared When light is irradiated onto the object, reflected light from the object begins to enter photodiode 102_(k). The potential of node 14_(k) starts to decrease from the potential at time T6.

[0176] At time T11, the reflected light from the object to the photodiode 102_(k) is The second imaging for the second infrared light irradiation is completed. is indicated by "H" to "L". Also, the potential of the signal line 12_(k) is maintained at "H". In addition, the potential of the node 14_(k) stops decreasing and becomes constant. The potential of the node 14_(k) is set to "V2."

[0177] The potential "V2" of the node 14_(k) at time T11 is the potential "V2" of the node 14_(k) from time T5 to time T6. The amount of light irradiated onto the photodiode 102_(k) during the period from time T10 to time T11 is determined based on the sum of the amount of light irradiated onto the photodiode 102_(k) during the .

[0178] At time T12, the potential of the signal line 12_(k) is changed from "H" to "L".

[0179] At time T13, the potential of the signal line 13_(k-1) is changed from "L" to "H" (first (Readout begins). A potential "H" is supplied to the gate electrode of transistor 105_(k-1). In addition, the signal line 15_(k-1) and the signal line 16_(k-1) are turned on. The input terminal 104_(k-1) becomes conductive through the transistor 105_(k-1).

[0180] The potential of the signal line 16_(k-1) starts to drop from "H".

[0181] Note that, before time T13, a precharge operation is performed on the signal line 16_(k-1). The potential of the signal line 16_(k-1) is set to "H".

[0182] The configuration of the read circuit that performs the precharge operation on the signal line 16_(k-1) is not particularly limited. For example, a read circuit 101 shown in FIG.

[0183] At time T14, the potential of the signal line 13_(k-1) is changed from "H" to "L" (first (End of readout) The transistor 105_(k-1) is cut off, and the signal line 16_(k-1) The potential of the signal line 16_(k-1) at time T14 stops decreasing and becomes constant. "V S1 "

[0184] The potential of the signal line 16_(k-1) at time T14 is “V S1 " by getting The total amount of light irradiated onto the photodiode 102_(k-1) during infrared light irradiation is detected. It is possible.

[0185] Furthermore, at time T14, the potential of the signal line 13_(k) is changed from "L" to "H" (second (Readout begins.) A potential "H" is applied to the gate electrode, and the transistor 105_(k) is turned on. In addition, the signal line 15_(k) and the signal line 16_(k) are connected to the transistor 104_( k), via transistor 105_(k), becomes conductive.

[0186] The potential of the signal line 16_(k) starts to drop from "H".

[0187] Before time T14, a precharge operation is performed on the signal line 16_(k) to The potential of line 16_(k) is set to “H”.

[0188] The configuration of the read circuit that performs the precharge operation on the signal line 16_(k) is not particularly limited.

[0189] At time T15, the potential of the signal line 13_(k) is changed from “H” to “L” (second read The transistor 105_(k) is cut off, and the potential of the signal line 16_(k) drops. The potential of the signal line 16_(k) at time T15 is set to "V S2 "and do.

[0190] The potential of signal line 16_(k) at time T15 is “V S2 " by obtaining two infrared After the light is irradiated, the total amount of light irradiated to the photodiode 102_(k) can be detected. Cut.

[0191] In addition, if the light intensity in the first and second infrared light irradiations is constant, At time T14, the potential difference between the low potential “L” and the signal line 16_(k-1) is “V S1 " and when At time T15, the potential difference between the low potential “L” and the signal line 16_(k) is “V S2 " is the irradiation period The period shall be proportional to the

[0192] In this embodiment, from time T5 to time T6 (from time T10 to time T11 The imaging period from time T3 to time T5 (from time T9 to time T10) is This is an example that is short compared to the period. S2 " is "V S1 Smaller than " .

[0193] At time T15, the optical sensor can obtain the first detection signal S1 and the second detection signal S2. In the above-described driving method, the first detection signal S1 and the second detection signal S2 are obtained. The object is irradiated with infrared light multiple times, and the reflected light from the object is detected by an adjacent photodiode. This makes it possible to detect the signal without any time lag.

[0194] Therefore, by applying the above-mentioned driving method to a plurality of pixels of a semiconductor device, the object to be detected can be detected. Even if the object is moving, the distance between each optical sensor and the detected object can be calculated more accurately. can.

[0195] <Method 3 of driving a semiconductor device> An example of a method for driving a semiconductor device having the optical sensor group 110 shown in FIG. 4 will be described with reference to FIG. By using this driving method, two different detection signals are obtained, and a semiconductor device is The distance to the object to be detected can be calculated. By forming the diode 102B overlapping the diode 102, distance information and image information can be obtained simultaneously. This can be done.

[0196] The distance is calculated by a signal processing circuit included in the semiconductor device. It is possible to carry out appropriate calculations based on the different detection signals obtained. The distance between the optical sensor that absorbs infrared light and a point on the object to be detected is the distance from the light source to the object to be detected. It is possible to calculate this by repeatedly irradiating and stopping the infrared light multiple times.

[0197] Furthermore, by shortening the period from the start to the end of infrared light irradiation and repeating it multiple times, The semiconductor device can accurately obtain the distance between the object to be detected and the optical sensor that absorbs infrared light. Cut.

[0198] As shown in FIG. 8, infrared light irradiation is performed multiple times for a period T. Note that the first infrared light irradiation The first infrared light irradiation is from time T2 to time T4, the second infrared light irradiation is from time T6 to time T8, and the third infrared light irradiation is from time T9 to time T10. The first infrared light irradiation is from time T12 to time T15, and the fourth infrared light irradiation is from time T18 to time T16. It is time T20, and the period T is extremely short.

[0199] The pulse (FD_2) of the node 14A is "H" during the high potential period and "L" during the low potential period. At time T25, the potential difference between the low potential "L" and the node 14A is represented as "V3." do.

[0200] The pulse (FD_3) of the node 14B is "H" during the high potential period and "L" during the low potential period. At time T9, the potential difference between the low potential "L" and the node 14B is "V1", and at time T2 1, the potential difference between the low potential "L" and node 14B is represented as "V2."

[0201] The pulse of the signal line 16A is “H” during the high potential period and “L” during the low potential period, and at time T2 The potential difference between the low potential "L" and the signal line 16A at 7 is "V S3 " is used.

[0202] The pulse of the signal line 16B is “H” during the high potential period and “L” during the low potential period, and at time T1 The potential difference between the low potential "L" and the signal line 16B at 1 is "V S1 "And at time T24, The potential difference between the low potential "L" and the signal line 16B is "V S2 " is used to represent this.

[0203] At time T11, the potential difference between the low potential "L" and the signal line 16B is "V S1 " is the first The potential difference between the low potential "L" and the signal line 16B at time T24 corresponds to the detection signal S1. V S2 " corresponds to the second detection signal S2, and at time T27, the low potential "L" and the signal line 16A The potential difference between S3 " corresponds to the third detection signal S3.

[0204] In addition, in FIG. 8, the delay period ΔT is from time T2 to time T3, from time T6 to time T7, This corresponds to time T12 to time T13 and time T18 to time T19.

[0205] In FIG. 8, the period T is fixed for the four infrared light irradiations.

[0206] Furthermore, it is assumed that the distance from the light source to the object to be detected does not change during the period in which the image is captured. Therefore, the delay period ΔT can be assumed to be equal for the four infrared light irradiations.

[0207] In FIG. 8, as an example, infrared light for acquiring the first detection signal and the second detection signal is used. Irradiation was performed twice for each treatment, but it is also effective to perform it three or more times, and the number of times is not particularly limited. However, the number of infrared light irradiations to obtain the first detection signal and the number of infrared light irradiations to obtain the second detection signal are not limited. The number of infrared light irradiations for obtaining the same value is set to be equal.

[0208] Next, a certain optical sensor that absorbs infrared light and a certain point on the object to be detected are connected to the semiconductor device. The method for calculating the distance is the same as that of the driving method 1 of the semiconductor device, and therefore the explanation is omitted. Omitted.

[0209] Next, a specific method for driving the semiconductor device will be described with reference to the timing chart shown in FIG. He explains.

[0210] The optical sensor group 110 includes a photodiode 102A that absorbs visible light and transmits infrared light. Since the photodiode 102B that absorbs infrared light is superimposed on the photodiode 102A, three-dimensional imaging is possible. It is possible to perform both 3D and 2D imaging simultaneously.

[0211] First, the three-dimensional imaging for acquiring three-dimensional distance information will be described. At times T1 to T27, the first detection signal S1 and the second detection signal S2 are acquired. This can be seen from the driving method of the optical sensor 100 described in the semiconductor device driving method 1. Such a driving method is applied to a plurality of pixels of a semiconductor device. By applying this technology, the distance between the object and the optical sensor that absorbs the infrared light can be measured more accurately. It can be calculated as follows.

[0212] Next, two-dimensional imaging for acquiring two-dimensional image information will be described.

[0213] At time T1, the potential of the signal line 11A is changed from "L" to "H" (reset operation). Then, the potential of the signal line 12A is changed from "L" to "H". At this time, the photodiode 102A The transistor 103A is turned on, and the potential of the node 14A becomes "H".

[0214] At time T2, the potential of the signal line 11A is changed from "H" to "L". maintains "H". The potential of the node 14A starts to drop from "H".

[0215] Imaging is started to obtain two-dimensional image information.

[0216] From time T3 to time T25, the potential of the signal line 12A is maintained at “H”. The potential of the node 14A continues to decrease from "H".

[0217] At time T25, the potential of the signal line 12A is changed from "H" to "L". The decline in the level stops and becomes constant.

[0218] Imaging for acquiring two-dimensional image information is then completed.

[0219] The potential of the node 14A at time T25 is the potential of the photodiode between time T3 and time T25. The potential change is determined based on the amount of light irradiated to the diode 102A. Get bigger.

[0220] At time T26, the potential of the signal line 13A is changed from "L" to "H" (readout starts). A potential "H" is supplied to the gate electrode of the transistor 105A, and the transistor 105A is turned on. 5A and signal line 16A are conductive through transistor 104A and transistor 105A. do.

[0221] The potential of the signal line 16A starts to drop from "H".

[0222] Note that, before time T26, a precharge operation is performed on the signal line 16A. Let the potential of A be "H".

[0223] At time T27, the potential of the signal line 13A is changed from "H" to "L" (reading ends). The transistor 105A is turned off, and the potential of the signal line 16A stops decreasing and becomes constant. The potential of the signal line 16A at time T27 is expressed as "V S3 "

[0224] The potential of the signal line 16A at time T27 “V S3 " by obtaining the photodiode The amount of light irradiated onto 102A can be detected.

[0225] When the light intensity is constant, the potential of the signal line 16A is “V S3 " is roughly proportional to the duration of irradiation. .

[0226] At time T27, the optical sensor group 110 outputs a first detection signal S1, a second detection signal S2, and the third detection signal S3 can be obtained.

[0227] By applying the above-mentioned driving method to a plurality of pixels of a semiconductor device, The distance between the infrared light absorbing optical sensor and the object to be detected is calculated, while the visible light absorbing optical sensor This allows image information of the detected object to be obtained.

[0228] Note that this embodiment mode can be appropriately combined with other embodiment modes described in this specification. .

[0229] (Embodiment 2) In this embodiment, the infrared light irradiation period T is not fixed from the beginning, and the infrared light is emitted from the semiconductor device to the object to be detected. Taking into account the distance at, the period T is adjusted to improve the accuracy of the detection signal and calculate the distance x. The method will be explained with reference to FIG.

[0230] As described in the first embodiment, the accuracy of the detection signal depends not only on the number of infrared light irradiations but also on the infrared light irradiation time. It also depends on the proportion of the delay period ΔT in the irradiation period T.

[0231] In addition, the period T must be at least longer than the delay period ΔT, and must be extremely short. It is preferable that the infrared light irradiation period is set to Tb It is preferable to set the period Ta to be shorter than the period T. The ratio of the delay period ΔT to the period T can be increased accordingly. The detection accuracy can be improved by increasing the change in the detection signal relative to the distance x. , resulting in improved accuracy of the distance x.

[0232] In the first embodiment, the detection signal is proportional to the net exposure time, that is, the proportionality coefficient α is assumed to be constant. However, more generally, the proportionality coefficient α is not constant. This is because the proportional coefficient α depends not only on the net exposure time but also on the amplification factor of the optical sensor, This is because it may also depend on the amplification factor of the output circuit.

[0233] Therefore, in order to further improve the accuracy of distance detection as in this embodiment, the first detection signal S It is effective to adjust the period T so that the first and second detection signals S1 and S2 are equal. Here, the fact that the first detection signal S1 and the second detection signal S2 are equal means that the first detection signal S1 When acquiring the first detection signal S1, the charge accumulated at the node FD is equal to that when acquiring the second detection signal S2. This means that the amount of light irradiated on the photodiode is equal. If the intensity of the reflected light is constant during the period during which it is incident on the object to be detected, then the above condition is satisfied. is only true if ΔT = T / 2 holds.

[0234] That is, the period T is changed so that the first detection signal S1 and the second detection signal S2 become equal. When the distance to the object is adjusted as above, the distance to the object calculated according to formula (A) is It can be specified independently of the amplification factor, the amplification factor of the output circuit, etc.

[0235] As a specific example, the first detection signal S1 and the second detection signal S 2 are sequentially acquired, and when the period T is set to 1 nsec, the first detection signal S 1m And the second test Output signal S 2m According to formula (A), from the period T and the speed of light c, The distance x is calculated to be about 7.5 cm. This distance depends on the amplification factor of the optical sensor and the output circuit. It does not depend on the amplification factor, etc.

[0236] In order to calculate the distances to multiple points on the object with high accuracy, the period T must be kept constant. While doing so, the first detection signal S1 and the second detection signal S2 at each point are sequentially acquired, and the first detection signal S1 and the second detection signal S2 are When the output signal S1 and the second detection signal S2 become equal, the first detection signal S 1m , 2nd Detection signal S 2m , and the period T, the distance is determined according to formula (A): At each point, the distance is calculated while setting the period T so that the detection accuracy is highest. It is possible.

[0237] In this embodiment, it is also preferable to irradiate infrared light many times.

[0238] This makes it possible to calculate highly accurate distance information and significantly reduce the overall measurement time.

[0239] Note that this embodiment mode can be appropriately combined with other embodiment modes described in this specification. .

[0240] (Embodiment 3) In this embodiment, the configuration of the optical sensor 100 shown in the first embodiment will be described in more detail. The configuration of a semiconductor device having optical sensors 100 arranged in a matrix of m rows and n columns will be described. 10(A) is used to show an example of the above, and FIG. 10 is used to show an example of a configuration different from that of FIG. This will be explained using (B).

[0241] In FIG. 10A, a plurality of optical sensors 100 are arranged in a matrix of m rows and n columns. The optical sensors 100 in each row are connected to a plurality of signal lines 11(PR) (11(PR)_1 to 11(PR) _m) and multiple signal lines 12(TX) (12(TX)_1~1 2(TX)_m) and multiple signal lines 13(SE) (13(SE Each column is electrically connected to one of the columns (represented as 1 to 13(SE)_m). The optical sensor 100 includes a plurality of optical sensor output signal lines (represented as 16_1 to 16_n). One of the multiple optical sensor reference signal lines (denoted as 15_1 to 15_n) is electrically connected to one

[0242] In FIG. 10A, the signal line 12 (TX) is shared among the optical sensors in each row. The signal line 11 (PR) is shared among the photosensors in each row, and the signal line 13 (SE) is shared among the photosensors in each row. The optical sensor output signal line is shared between the optical sensors in each column. The optical sensor reference signal line is shared. However, the present invention is not limited to this. A plurality of signal lines 12 (TX) are provided to electrically connect the different optical sensors 100 to each other. A plurality of signal lines 11 (PR) may be provided in each row to electrically connect different optical sensors 100 to each other. Alternatively, a plurality of signal lines 13 (SE) may be provided in each row to connect different optical sensors. Each column may be provided with a plurality of optical sensor output signal lines, each of which may be electrically connected to the optical sensor 100. Each row may be electrically connected to the optical sensor 100. The light sensors 100 may be electrically connected to different light sensors 100 in different positions.

[0243] In addition, in FIG. 10A, a configuration in which the optical sensor reference signal line is shared by the optical sensors of each column is shown. However, the present invention is not limited to this. The optical sensor reference signal line may be shared by the optical sensors in each row. good.

[0244] In addition, among the optical sensors 100 arranged in a matrix of m rows and n columns, the reset operation, accumulation The signal line 12 (TX) can be shared between the optical sensors 100 that operate simultaneously. The reset operation, the accumulation operation, and the like of the optical sensors 100 arranged in a matrix of m rows and n columns In the photosensor performing the above simultaneously, the signal line 11 (PR) can be shared.

[0245] As described above, by sharing the wiring and reducing the number of wiring, the This allows the drive circuit for driving the optical sensor 100 placed thereon to be simplified.

[0246] Next, a three-dimensional distance measuring device having optical sensors 100 arranged in a matrix of m rows and n columns is An example of a configuration of the device different from that of FIG. 10(A) will be described with reference to FIG. 10(B).

[0247] In FIG. 10B, a plurality of optical sensors 100 are arranged in a matrix of m rows and n columns. The optical sensors 100 in each row are connected to a plurality of signal lines 13(SE) (13(SE)_1 to 13(SE) The optical sensors 100 in each row are electrically connected to one of the optical sensors 100 in each row. Any of the multiple signal lines 11(PR) (referred to as 11(PR)_1 to 11(PR)_n) or one and multiple signal lines 12(TX) (written as 12(TX)_1 to 12(TX)_n) ) and one of multiple optical sensor output signal lines (referred to as 16_1 to 16_n). One of the multiple optical sensor reference signal lines (denoted as 15_1 to 15_n) is electrically connected to one

[0248] In FIG. 10B, the photosensors in each row share a signal line 13 (SE), and the photosensors in each column The signal line 11 (PR) is shared among the photosensors in each row, and the signal line 12 (TX) is shared among the photosensors in each row. The optical sensor output signal line is shared between the optical sensors in each column. The photosensor reference signal line is shared, however, the present invention is not limited to this.

[0249] FIG. 10B shows a configuration in which the photosensor reference signal line is shared by the photosensors in each column. However, the present invention is not limited to this. The photosensor reference signal line may be shared by the photosensors in each row.

[0250] In addition, among the optical sensors 100 arranged in a matrix of m rows and n columns, the reset operation, accumulation The signal line 12 (TX) can be shared by optical sensors that operate simultaneously. The reset operation and the accumulation operation are simultaneously performed on the optical sensors 100 arranged in a matrix of n columns. In the optical sensors, the signal line 11 (PR) can be shared.

[0251] As described above, by sharing the wiring and reducing the number of wiring, the This allows the drive circuit for driving the optical sensor 100 placed thereon to be simplified.

[0252] FIG. 11(A) shows a top view of the optical sensor 100, and FIG. 11(B) shows the dotted line in FIG. 11(A). A cross-sectional view taken along line A1-A2 is shown.

[0253] The optical sensor 100 includes a conductive film 210 that functions as a signal line 11 (PR) and a signal line 12 (T A conductive film 211 functioning as a signal line 13 (SE) and a conductive film 212 functioning as a signal line 13 (SE). A conductive film 213 that functions as a signal line 15 (a photosensor reference signal line) and a signal line 16 (a photosensor reference signal line) are provided. and a conductive film 214 that functions as a sensor output signal line.

[0254] The photodiode 102 of the optical sensor 100 is made up of a p-type semiconductor film 21 5, an i-type semiconductor film 216, and an n-type semiconductor film 217. The conductive film 210 , which is electrically connected to a p-type semiconductor film 215 that functions as the anode of the photodiode 102. It is being done.

[0255] The conductive film 218 of the optical sensor 100 functions as a gate electrode of the transistor 103. The conductive film 211 is electrically connected to the photodetector 100. The film 219 functions as one of the source and drain electrodes of the transistor 103 . The conductive film 220 of the optical sensor 100 serves as a source electrode or a drain electrode of the transistor 103. The conductive film 221 of the optical sensor 100 is an n-type semiconductor film 2 17 and the conductive film 219 of the optical sensor 100. 2 functions as a gate electrode of the transistor 104 and is further connected to a conductive film 220. are electrically connected.

[0256] The conductive film 223 of the optical sensor 100 serves as a source electrode or a drain electrode of the transistor 104. The conductive film 224 of the optical sensor 100 functions as one of the electrodes. The other of the source electrode or drain electrode of transistor 4 and the source electrode or drain electrode of transistor 105 The conductive film 214 functions as one of the source electrodes of the transistor 105. The conductive film 212 serves as the other of the gate and drain electrodes of the transistor 105. The conductive film 225 of the optical sensor 100 also functions as a conductive electrode. It is electrically connected to the conductive film 213.

[0257] In FIG. 11, the conductive film 226 of the optical sensor 100 is used as the signal line 11 (PR). The photodetector 100 is electrically connected to the conductive film 210 that functions as a photodetector. 227 is electrically connected to the conductive film 211 which functions as the signal line 12 (TX).

[0258] Conductive film 212, conductive film 218, conductive film 222, conductive film 225, conductive film 226, conductive film 22 7 can be formed by processing a conductive film formed on an insulating surface into a desired shape. The conductive film 212, the conductive film 218, the conductive film 222, the conductive film 225, the conductive film 226, A gate insulating film 228 is formed on the conductive film 227. 211, conductive film 213, conductive film 214, conductive film 219, conductive film 220, conductive film 223, The conductive film 224 is formed by processing a conductive film formed on a gate insulating film 228 into a desired shape. It can be formed by:

[0259] In addition, the conductive film 210, the conductive film 211, the conductive film 213, the conductive film 214, the conductive film 219, An insulating film 281 and an insulating film 282 are formed on the film 220, the conductive film 223, and the conductive film 224. The conductive film 221 is formed on the insulating film 281 and the insulating film 282.

[0260] The active layer 250 of the transistor 103 is preferably made of an oxide semiconductor. In order to hold the charge generated by the light irradiation from the 51 side for a long time, The transistor 103 electrically connected to the diode 102 is Therefore, the active layer 250 is made of an oxide semiconductor material. By using it, the performance of the optical sensor 100 can be improved.

[0261] In the case where the transistor 103 is a bottom-gate transistor, as shown in FIG. It is possible to use a configuration in which the active layer 250 completely overlaps the conductive film 218 that functions as a gate electrode. By adopting the above-mentioned configuration, the active layer 250 is irradiated with light incident from the substrate 251 side. This prevents the oxide semiconductor in the transistor 103 from deteriorating, thereby shifting the threshold voltage of the transistor 103. This can prevent the deterioration of characteristics such as the transistor 10 being caused. The same effect can be obtained by adopting the above-mentioned configuration for the transistor 4 and the transistor 105. do.

[0262] The semiconductor layer used for the transistor 104 may be polycrystalline silicon, single crystal silicon, or the like. Which material is preferred?

[0263] The semiconductor layer used for the transistor 105 may be polycrystalline silicon, single crystal silicon, or the like. Which material is preferred?

[0264] Here, in the structure in which the signal line 12 (TX) as shown in FIG. 10(A) is arranged extending in the row direction, In the case of the pixel structure, the signal line 13 (S) is arranged to extend in the row direction and is parallel to the signal line 12 (TX). The signal line 13 (SE) is electrically connected to the gate electrode of the transistor 105. Therefore, a part of the signal line 13 (SE) is used as the gate electrode of the transistor 105. The signal line 12 (TX) parallel to the signal line 13 (SE) also Generally, the gate electrode is formed in the same layer as the gate electrode and made of the same material. The material used for the gate electrode of a transistor is the same as that used for the source and drain electrodes. It is a material that generally has a high resistance compared to other materials. Therefore, the resistance of the signal line 12 (TX) is It tends to be higher.

[0265] In contrast, in the configuration shown in FIG. 10B, the signal line 12 (TX) is arranged to extend in the column direction. Therefore, a signal line 13 (SE) arranged in the row direction is different from the signal line 13 (SE). The signal line 12 (TX) can be formed using the conductive film formed on the layer. For example, As shown in FIG. 11, the transistors constituting the optical sensor 100 (transistor 103, The conductive film (conductive film 2) constituting the gate electrodes of the transistors 104, 105, etc. 12, conductive film 218, conductive film 222) is formed in a different layer. The conductive film 211 can form the line 12 (TX). 9, the conductive film 220, the conductive film 224, etc., the transistors constituting the optical sensor 100 The source and drain electrodes of the transistors 103, 104, 105, etc. The source electrode and the drain electrode can be formed in the same layer using the same material. Therefore, the resistance of the signal line 12 (TX) is made smaller than that of the configuration shown in FIG. It is possible.

[0266] Note that this embodiment mode can be appropriately combined with other embodiment modes described in this specification. .

[0267] (Embodiment 4) In this embodiment, a photodiode having the optical sensor described in any of the above-described Embodiments 1 to 3 is used. An example of the configuration of an organic EL display device will be described with reference to FIG. On a crystalline semiconductor substrate (for example, a single crystal silicon substrate), three n-channel transistors and The photodiode is laminated on the photodiode.

[0268] The substrate 411 is made of single crystal silicon with a relatively high resistance (for example, n-type, about 10 Ωcm). The n-wells 412, 413, 414, and 415 are formed in a self-aligned manner. The transistors are separated by field oxide 416. Formation of Field Oxide 416 In this case, boron (B) is selectively introduced into the substrate by ion implantation to form a channel strip. A top may be formed.

[0269] The gate insulating films 417, 418, and 419 are formed by thermal oxidation.

[0270] The gates 420, 421, and 422 are polycrystalline silicon films formed by CVD to a thickness of 100 to 300 nm. and polycrystalline silicon layers 420a, 421a, and 422a formed to a thickness of 50 to 100 nm. The silicide layers 420b, 421b, and 422b are stacked to a thickness of 300 nm. The polysilicon layer is pre-etched at 1000 nm to reduce its resistance. 21 / cm 3 At a concentration of about The polysilicon film may be doped with n-type impurities after the polysilicon film is formed. The material of the silicide layer is molybdenum silicide (MoSi x ), Tan silicide (WSi x ), Tantalum silicide (TaSi x ), titanium silicide TiSi x ) or the like can be applied, and the formation may be performed according to a known method.

[0271] The lightly doped drain (LDD) regions 423, 424, and 425 of the n-channel transistor are The impurity element that gives n-type conductivity is phosphorus (P) or arsenic (As) at a dose of 1× 10 13 ~1×10 14 / cm2 These LDD regions are masked by the gate. The gate insulating film is formed in a self-aligned manner by ion implantation or ion doping.

[0272] In this embodiment, as an example, the transistor 403, the transistor 404, Although the transistor 405 is an n-channel transistor, the present invention is not limited to this configuration. The transistor 403, the transistor 404, and the transistor 405 are p-channel transistors. It may be a diode, or a mixture of n-channel and p-channel types.

[0273] When fabricated with a p-channel transistor, the low concentration drain of the p-channel transistor In the laser diode doping (LDD) region, boron (B) is added at a dose as an impurity element to give p-type conductivity. 1×10 13 ~1×10 14 / cm 2 Just add it in this way.

[0274] After the LDD region is formed, the entire surface is covered with a silicon oxide film, silicon nitride film, etc. by the CVD method. The insulating film is formed by etching the entire surface of the insulating film uniformly. By leaving the insulating film on the side walls of the gate, the side walls 426, 427, and 428 are The source and drain regions of each transistor are formed on the sidewall. The film is formed using a mask.

[0275] For n-channel transistors, arsenic (As) was added at 5×10 14 ~1×10 16 / cm 2 The source regions 430, 431, and 432 and the drain region 433 are implanted with a dose of 1000 .mu.m. 33, 434, and 435 are formed.

[0276] When making a p-channel transistor, boron (B) is added at 5×10 14 ~1×10 1 6 / cm 2 The source and drain regions may be formed by implanting ions at a dose of 100 .mu.m.

[0277] The first interlayer insulating film 436 is preferably an oxide film formed by a plasma CVD method or a low pressure CVD method. It is made of silicon film or silicon oxynitride film with a thickness of 100 to 2000 nm. do.

[0278] Further, phosphorus glass (PSG) or boron glass (BS G), or a second interlayer insulating film 437 is formed using phosphorus boron glass (PBSG) or the like. The second interlayer insulating film 437 is formed by a spin coating method or a normal pressure CVD method. After the formation, the second layer is formed by a heat treatment at 700 to 900 °C, which also serves as a thermal activation treatment. The interlayer insulating film 437 is reflowed to flatten the surface.

[0279] The source wirings 440, 441, and 442 and the drain wirings 443, 444, and 445 are the first Contact holes are formed in the interlayer insulating film 436 and the planarized second interlayer insulating film 437. After that, the source and drain regions of the respective n-channel transistors are contacted with The source and drain wiring are usually made of low-resistance material. It is preferable to use aluminum, which can be used for the insulation. The material may be a laminated structure of a material such as a aluminum alloy or pure aluminum.

[0280] In addition, an electrode 446 is formed in the same layer as the source wiring and the drain wiring.

[0281] The passivation film 447 is a silicon nitride film or a silicon oxide film formed by the plasma CVD method. The insulating film is formed using a silicon oxide nitride film or the like.

[0282] Furthermore, a third interlayer insulating film 448 is formed on the passivation film 447. The surface of the interlayer insulating film 448 is reflowed and planarized.

[0283] A contact hole is formed in the passivation film 447 and the planarized third interlayer insulating film 448. An electrode 449 in contact with the electrode 446, an electrode 450 in contact with the source wiring 440, and An electrode 451 is formed in contact with the drain wiring 445 .

[0284] On the third interlayer insulating film 448, an electrode 452 in contact with the electrode 449 and an electrode 450 in contact with the electrode 450 are formed. An electrode 453 and an electrode 454 in contact with the electrode 451 are formed. The electrode 454 is preferably made of aluminum, which is commonly used as a low resistance material. Also, a laminated structure of titanium, aluminum, and titanium may be used.

[0285] The photodiode 402 formed on the upper side and the photodiode 403 formed on the lower side are separated by the electrodes 450 and 453. The transistor 403 formed in the second portion can be electrically connected to the first portion.

[0286] The photodiode 402 in FIG. 12 has a first electrode, a second electrode, and a The photoelectric conversion layer 460 is sandwiched between the electrodes. The photoelectric conversion layer 460 is a p-type semiconductor layer 460p , an n-type semiconductor layer 460n, and a p-type semiconductor layer 460p sandwiched between the n-type semiconductor layer 460n The semiconductor layer 460 has an intrinsic (i-type) semiconductor layer 460i.

[0287] The photodiode 402 is not limited to this configuration, and may have at least a p-type semiconductor layer and an n-type It is sufficient that the semiconductor layer has a laminated structure.

[0288] The p-type semiconductor layer 460p is a semi-amorphous layer containing a Group 13 impurity element, for example, boron (B). The fast silicon film may be formed by plasma CVD, or the semi-amorphous silicon film may be formed by After the GaN film is formed, a Group 13 impurity element may be introduced.

[0289] After the p-type semiconductor layer 460p is formed, a conductive A semiconductor layer that does not contain impurities that give The i-type semiconductor layer 460i is, for example, a semi-amorphous silicon film. may be formed by a plasma CVD method.

[0290] Furthermore, an n-type semiconductor layer 460n is formed by stacking on the intrinsic (i-type) semiconductor layer 460i. The n-type semiconductor layer 460n contains a Group 15 impurity element, for example, phosphorus (P). A semi-amorphous silicon film including the amorphous silicon may be formed, or the semi-amorphous silicon film may be formed. After this, a Group 15 impurity element may be introduced.

[0291] As a result, the p-type semiconductor layer 460p, the i-type semiconductor layer 460i, and the n-type semiconductor layer 460n are A photoelectric conversion layer 460 having the above structure is formed.

[0292] In this specification, the i-type semiconductor layer refers to a semiconductor layer that is provided with a p-type or n-type. The impurity concentration is 1×10 20 cm -3 Oxygen and nitrogen are 5×10 or less. 19 cm -3 The photoconductivity is more than 1000 times higher than the dark conductivity. It is preferable that the i-type semiconductor layer contains 10 to 1000 ppm of boron (B). It may be possible.

[0293] In addition, an intrinsic (i-type) semiconductor layer 460i, a p-type semiconductor layer 460p, and an n-type semiconductor layer 460 n, not only semi-amorphous semiconductor films but also amorphous semiconductor films can be used. good.

[0294] A fourth interlayer insulating film 455 is formed on the electrode 452, the electrode 454, and the photoelectric conversion layer 460. The fourth interlayer insulating film 455 is made of an organic resin material. The fourth interlayer insulating film 455 is formed with a thickness of 1 μm to 2 μm by applying a After the coating is completed, a thermally polymerized polyimide is used and heated to 300°C in a clean oven. It may be formed by firing.

[0295] Organic resin materials include polyimide, polyamide, acrylic, and benzocyclobutene (B The advantage of using organic resin materials is that the film formation method is The method is simple, the dielectric constant is low, so parasitic capacitance can be reduced, and it is suitable for planarization. Of course, organic resin materials other than those mentioned above may be used.

[0296] A pixel electrode 456 is formed on the fourth interlayer insulating film 455. The electrode 451 is electrically connected to the drain wiring 445 of the transistor 405 via the electrode 454. The electrode 451 and the electrode 454 connect the pixel electrode 456 and the transistor 40 5 can be electrically connected.

[0297] The pixel electrode 456 is preferably made of a low resistance material such as Al. The film can be formed by a known film forming method, such as a vacuum deposition method or a sputtering method. In order to improve the contrast, the surface of the pixel electrode 456 is made uneven to serve as a diffuse reflection surface. That's fine.

[0298] Furthermore, a first transparent conductive film is formed on the pixel electrode 456 and the fourth interlayer insulating film 455. According to the photolithography method, a partial etching process is performed, and the transparent conductive film 457, 45 8 is formed.

[0299] The transparent conductive film 457 is formed so as to be in contact with the pixel electrode 456 and serves as an anode or a cathode of the light-emitting element. The light-emitting element functions as a light-emitting element. and an organic EL layer sandwiched between the electrodes.

[0300] The transparent conductive film 458 is connected to the fourth interlayer insulating film 455 through a contact hole. The electrode 452 is formed in contact with the n-type semiconductor layer 460n.

[0301] The transparent conductive films 457 and 458 are made of indium tin oxide (ITO, Indium Ti n Oxide) can be used.

[0302] A transparent conductive film 458 formed on the upper side and a conductive film 459 formed on the lower side are formed through the electrodes 449 and 452. The electrode 446 formed on the substrate 441 can be electrically connected to the substrate 441 .

[0303] A plurality of inversely tapered partition walls 46 are formed on the transparent conductive films 457 and 458 and the fourth interlayer insulating film 455. The cross section of the partition wall 461 has an inverted tapered shape, and the upper surface has a frame shape. The frame shape may be a curved shape without a vertex, and may have at least two corners. It is sufficient that the closed loops are not in contact with each other and that there is a cavity in the center. 1 is a photolithographic method using a positive photosensitive resin with the unexposed areas as a pattern. By adjusting the exposure dose or development time, the lower part of the pattern is etched more. It is formed by:

[0304] An organic EL layer (electroluminescence layer) 45 is formed on the partition wall 461 and the transparent conductive film 457. The organic EL layer 459 may be made of a known material or have a known structure.

[0305] The organic EL layer 459 is composed of only a light-emitting layer that provides a site for recombination. Alternatively, an electron injection layer, an electron transport layer, a hole transport layer, an electron blocking layer, a hole blocking layer, etc. may be formed as necessary. Alternatively, a hole injection layer may be laminated. The organic EL layer 459 is made of a polymer organic material. EL materials can be used.

[0306] As an example, the organic EL layer 459 is made of PVK (polyvinylcarbazole), Bu-PBD ( 2-(4'-tert-butylphenyl)-5-(4''-biphenyl)-1,3,4- oxadiazole), coumarin 6, DCM1 (4-dicyanomethylene-2-methyl-6- p-Dimethylaminostyryl-4H-pyran), TPB (Tetraphenylbutadiene), Nile Red is dissolved in 1,2-dichloromethane or chloroform and then spin-coated. The insulating layer 11 may be formed by coating using the above method.

[0307] A second transparent conductive film is formed on the partition wall 461, the organic EL layer 459, and the transparent conductive film 458. Then, a part of the substrate is etched by photolithography to form a transparent conductive film 4. The transparent conductive films 462 and 463 are formed. ITO or the like is used for the transparent conductive films 462 and 463. It is possible.

[0308] The transparent conductive film 462 is formed so as to be in contact with the organic EL layer 459 and serves as an anode or a cathode of the light-emitting element. It functions as a pole.

[0309] In the present embodiment, one of the transparent conductive films 457 and 462 is an anode. As long as the other electrode is a cathode, either one is acceptable.

[0310] The height of the partition wall 461 is formed to be greater than the thickness of the second transparent conductive film. Therefore, the transparent conductive film 462 and the transparent conductive film 463 are formed in a plurality of regions. The divided regions are electrically independent of each other. The potential of the transparent conductive film is floating.

[0311] In addition, since the light to be detected passes through the transparent conductive film 458 and the transparent conductive film 463, these materials It is preferable that all of the materials used are highly light-transmitting.

[0312] If necessary, a sealing material such as a sealing can or a glass substrate may be attached to the substrate 411. The light emitting element may be disposed in a sealed space by bonding and sealing with an adhesive. This makes it possible to prevent the light emitting element from deteriorating. In addition, the light emitting element may be filled with a material such as a dry inert gas. To prevent this, a desiccant or the like may be placed between the substrate and the sealing material. The desiccant is removed and the material is thoroughly dried. The desiccant is calcium oxide or barium oxide. Use a substance that adsorbs moisture by chemical adsorption, such as an oxide of an alkaline earth metal. Other drying agents such as zeolite and silica gel can be used by physical adsorption. Alternatively, a material that absorbs moisture may be used.

[0313] The transistors 403, 404, and 405 are formed of a silicon film or the like on an insulating surface. A transistor in which a channel formation region is formed in a semiconductor film or a silicon film of an SOI substrate. As for the configuration of the transistor, other known configurations can be used. be.

[0314] In addition, in FIG. 12, a layer in which a photodiode 402 is formed and transistors 403 and 4 A structure in which one wiring layer is provided between the layers on which 04 and 405 are formed is shown. There is no limitation to this, and a configuration in which two or more wiring layers are provided may also be used.

[0315] As described above, the photodiode 402 and the transistors 403, 404, and 405 are integrated. By layering, the area of ​​the optical sensor can be reduced, making it possible to achieve miniaturization.

[0316] This embodiment mode can be implemented in appropriate combination with any of the above embodiment modes.

[0317] (Embodiment 5) In the present embodiment, the adjacent optical sensor 100_(k−1) and the optical sensor 100_(k−2) shown in the first embodiment are The configuration of the optical sensor 100_(k) (hereinafter collectively referred to as the optical sensor group 120) will be described in more detail. The semiconductor device has a group of optical sensors 120 arranged in a matrix of m rows and n columns. An example of the configuration of the body device will be described with reference to FIG.

[0318] In FIG. 13A, the optical sensor 100_(s) and the optical sensor 100_(s+1) are in adjacent columns. In this example, reflected light from the same point on the subject is detected (s is 1 or more (2n- 1) or less odd numbers). In FIG. 13B, optical sensor 100_(i) and optical sensor 100_ (i+1) shows an example of detecting reflected light from the same point on the subject in the adjacent row ( i is an odd number between 1 and (2m-1). The same effect can be obtained in either configuration. Therefore, the configuration is not limited.

[0319] In FIG. 13A, a plurality of optical sensor groups 120 are arranged in a matrix of m rows and n columns. For example, adjacent optical sensors 100_(s) and 100_(s+1) in the first row Similarly, the mth row of adjacent photosensors detects reflected light from the same point on the subject. 100_(s) and at light sensor 100_(s+1), reflections from the same point on the object Detect light.

[0320] The optical sensor group 120 in each row shares the optical sensor reference signal line 15. For example, The optical sensor reference signal line 15_(1) is connected to the optical sensor group 120_(1) in the 1st row and 1st column to the optical sensor group 120_(1) in the 1st row and nth column. The m-th row of the optical sensor reference signal line 15 is electrically connected to the m-th row of the optical sensor group 120 (n). In FIG. 1(m), the optical sensor group 120_(1) in the mth row and the first column to the optical sensor group 120_(2) in the mth row and the nth column are also shown. _(n) and is electrically connected.

[0321] In addition, the optical sensor groups 120 in each row share the optical sensor output signal lines 16. The optical sensor output signal line 16_(1) in the 1st row corresponds to the optical sensor group 120_(1)-1 An optical sensor output signal line in the mth row is electrically connected to the optical sensor group 120_(n) in the nth row and column. 16_(m) also includes the optical sensor group 120_(1) in the mth row and the 1st column to the optical sensor group 120_(1) in the mth row and the nth column. 120_(n) and is electrically connected thereto.

[0322] In FIG. 13A, the photosensor reference signal line 15 is shared among the photosensors in each row. The output signal line 16 is shared.

[0323] However, the present invention is not limited to this. For example, each column may have multiple optical sensor reference signals. Wires 15 may be provided to electrically connect different photosensors to each other. Photosensor output signal lines 16 may be provided to electrically connect different photosensors.

[0324] In FIG. 13A, the optical sensor reference signal lines 15 and the optical sensor output signal lines 16 are arranged in a row. Although the configuration in which the optical sensor is shared is shown, the present invention is not limited to this. The photosensor output signal line 16 may be shared by the photosensors in each column.

[0325] As described above, by sharing the wiring and reducing the number of wiring, the This allows simplification of the drive circuitry for driving the group of optical sensors disposed thereon.

[0326] Next, a diagram of a semiconductor device having a group of photosensors 120 arranged in a matrix of m rows and n columns is shown. An example of a configuration different from that shown in FIG. 13(A) will be described with reference to FIG. 13(B). In the example shown in FIG. 1, a plurality of optical sensor groups 120 are arranged in a matrix of m rows and n columns. The object is detected by the optical sensor 100_(i) and the optical sensor 100_(i+1) adjacent to the eye. Similarly, the light reflected from the same point on the body is detected by the adjacent light sensor 100_(i) in the nth row. , and optical sensor 100_(i+1) detects reflected light from the same point on the subject.

[0327] The optical sensor group in each row shares a signal line 13. For example, the signal line 13_(1) in the first row The optical sensor group 120_(1) in the first row and first column to the optical sensor group 120_(n) in the first row and nth column are The m-th row signal line 13 is also electrically connected to the m-th row and the first column optical sensor group 120_(1). The optical sensor group 120_(n) is electrically connected to the optical sensor group 120_(n) in the mth row and the nth column.

[0328] In addition, the optical sensor reference signal line 15 is shared among the optical sensor groups in each column. As shown in FIG. 1B, the optical sensor reference signal line 15 is shared among the optical sensor groups in the n-th column. do.

[0329] However, the present invention is not limited to this. For example, each column may have multiple optical sensor reference signals. Lines 15 may be provided to electrically connect the different photosensors to each other.

[0330] In FIG. 13B, the photosensor reference signal line 15 is shared among the photosensors in each column. In addition, although the signal line 13 is shared among the photosensors in each row, the present invention is not limited to this. The photosensor reference signal line 15 may be shared among the photosensors in each row, or the signal line 13 may be It may be shared among the photosensors in the row.

[0331] As described above, by sharing the wiring and reducing the number of wiring, the This allows simplification of the drive circuitry for driving the group of optical sensors disposed thereon.

[0332] This embodiment mode can be implemented in appropriate combination with any of the above embodiment modes.

[0333] (Embodiment 6) Next, an example of a top view and a cross-sectional view of the optical sensor group 110 shown in FIG. 14. The dashed lines A1-A2 and A3-A4 in FIG. A cross-sectional view is shown in FIG. 15(A), and a cross-sectional view corresponding to the dashed line B1-B2 in FIG. 14 is shown in FIG. As shown in B).

[0334] 15(A) will be described. In the cross-sectional view shown in FIG. A light-shielding layer 231 and a base film 232 are provided on the insulating film 232 .

[0335] A semiconductor layer of the photodiode 102B that absorbs infrared light is formed on and in contact with the base film 232. A p-type semiconductor region 203 and an i-type semiconductor region 204 are provided, and the transistor 104B The n-type semiconductor region 205 and the i-type semiconductor region 206 constituting the semiconductor layer are provided. The n-type semiconductor region 207 and the i-type semiconductor region 208 that constitute the semiconductor layer of the transistor 105B An n-type semiconductor region 209 that constitutes the semiconductor layer of the transistor 103A is provided. can be.

[0336] In addition, the p-type semiconductor region 203 and the i-type semiconductor region 204, the n-type semiconductor region 205 and the i-type A semiconductor region 206, an n-type semiconductor region 207, and an i-type semiconductor region 208, 09 is formed in the same layer.

[0337] The semiconductor layer of the photodiode 102B, the semiconductor layer of the transistor 104B, the transistor An insulating layer 240 is provided on the semiconductor layer of the transistor 105B and the semiconductor layer of the transistor 103A. can be done.

[0338] The conductive layer 108 is provided on and in contact with the insulating layer 240. A gate electrode 241 of the transistor 104B is provided on the type semiconductor region 206. In addition, the gate of the transistor 105B is formed on the i-type semiconductor region 208 via the insulating layer 240. The conductive layer 108, the gate electrode 241, and the gate electrode 242 are , are formed in the same layer.

[0339] The conductive layer 108 is electrically connected to the signal line 15 (photosensor reference signal line).

[0340] An insulating layer is formed on the insulating layer 240, the conductive layer 108, the gate electrode 241, and the gate electrode 242. 243 will be established.

[0341] The n-type semiconductor region 207 of the transistor 105B is connected via the insulating layer 240 and the insulating layer 243. A conductive layer 255 is provided on one side of the n-type semiconductor region 2 of the transistor 104B. A conductive layer 245 is provided on one side of the n-type semiconductor layer 105B. The other side of the region 207 and the other side of the n-type semiconductor region 205 of the transistor 104B are in contact with each other. The conductive layer 255, the conductive layer 245, and the conductive layer 244 are formed by the same It is formed in layers.

[0342] The conductive layer 255 is connected to the signal line 16B (photosensor output signal line) and the transistor 105 B, and the conductive layer 245 is electrically connected to one of the source electrode and the drain electrode of the signal line 1 5, and electrically connected to one of the source electrode or the drain electrode of the transistor 104B. The conductive layer 244 is connected to the other of the source electrode and the drain electrode of the transistor 104B. It is electrically connected to the other of the source electrode or the drain electrode of the transistor 105B.

[0343] Similarly, the n-type semiconductor region of the transistor 103A is A conductive layer 247 is provided on and in contact with the p-type semiconductor region 209 of the photodiode 102B. A conductive layer 246 is provided on and in contact with the region 203. The conductive layer 247 and the conductive layer 246 are It is formed in layers.

[0344] The conductive layer 246 is electrically connected to the signal line 11B (reset signal line). 47 is electrically connected to one of the source electrode or the drain electrode of the transistor 103A. is.

[0345] In addition, a p-type semiconductor layer of the photodiode 102A is formed on the insulating layer 243 and the conductive layer 246. A body region 248, an i-type semiconductor region 249, and an n-type semiconductor region 230 are provided. The p-type semiconductor region 248 in the diode 102A has an end portion that runs over the conductive layer 246. It is formed by being pulled up.

[0346] The semiconductor layer of the photodiode 102A, the conductive layer 244, the conductive layer 245, the conductive layer 246, An insulating layer 233 is provided over the conductive layer 247 , the conductive layer 255 and the insulating layer 243 .

[0347] A conductive layer 252 is formed on the n-type semiconductor region 230 and the conductive layer 247 via an insulating layer 233. will be established.

[0348] The conductive layer 252 serves as a pixel electrode.

[0349] Next, FIG. 15(B) will be described. In the cross-sectional view shown in FIG. 15(B), the light-transmitting substrate 2 On the substrate 200, a light-shielding layer 231 and a base film 232 are provided.

[0350] A photodiode 102B that absorbs infrared light is disposed on the light-shielding layer 231 via the base film 232. The semiconductor layer is made up of a p-type semiconductor region 203, an i-type semiconductor region 204, and an n-type semiconductor region 253 will be provided.

[0351] An insulating layer 240 is provided on the semiconductor layer of the photodiode 102B and the base film 232. can be.

[0352] The conductive layer 108 is provided on and in contact with the insulating layer 240 .

[0353] An insulating layer 243 is provided on the insulating layer 240 and the conductive layer 108 .

[0354] The p-type semiconductor region 20 of the photodiode 102B is connected via the insulating layer 240 and the insulating layer 243. A conductive layer 246 is provided on and in contact with the n-type semiconductor region 2 of the photodiode 102B. A conductive layer 254 is provided on and in contact with the conductive layer 53. The conductive layer 246 and the conductive layer 254 are formed in the same layer. is formed.

[0355] The conductive layer 246 is electrically connected to the anode of the photodiode 102B. 54 is one of the source electrode or the drain electrode of the transistor 103B and the photodiode The cathode of the diode 102B is electrically connected to the cathode of the diode 102B.

[0356] On the semiconductor layer, the conductive layer 246, the conductive layer 254 and the insulating layer 243 of the photodiode 102A An insulating layer 233 is provided thereon.

[0357] The light-transmitting substrate 200 is a substrate made of a material that is transparent to visible light and infrared light. For example, a plastic substrate that is transparent to visible light and infrared light, a glass substrate, etc. A glass substrate or the like can be used.

[0358] Furthermore, the light-transmitting substrate 200 may be a light-transmitting flexible sheet or the like.

[0359] The light source (backlight) emits infrared light and visible light from the light-transmitting substrate 200 side. There is no particular limitation as long as it can be used. For example, a light emitting diode that emits infrared light and a light emitting diode that emits visible light can be used. Light-emitting diodes that emit light may be arranged side by side.

[0360] The light source detects visible light with a photodiode 102A and infrared light with a photodiode As long as it can be detected by 102B, it may be provided on the light-transmitting substrate 200 side or on the opposing substrate. It may be provided on the plate side.

[0361] The light-shielding layer 231 is made of aluminum, chromium, or the like that can block infrared light and visible light. A metallic material may be used.

[0362] By providing the light-shielding layer 231, infrared light and light emitted from a light source disposed on the light-transmitting substrate 200 side can be blocked. Prevents visible light from entering photodiode 102A and photodiode 102B It is possible.

[0363] The light-shielding layer 231 is not only formed in a region where the photodiode 102B is laminated, but also in a region where the transistor The semiconductor layers of the transistor 103, the transistor 104, and the transistor 105 are also overlapped with each other. It is preferable to provide a light-shielding layer in a region overlapping with the semiconductor layer of each transistor. Infrared and visible light from the light source cause characteristic degradation such as a shift in threshold voltage. This can prevent the following:

[0364] The undercoat film 232 may be made of silicon oxide, silicon nitride, silicon oxynitride, or silicon nitride oxide. It is preferable to use a material having light transmitting and insulating properties such as polycarbonate. The structure may be a laminated structure.

[0365] By providing the undercoat film 232, the alkali metals such as Na and Al contained in the light-transmitting substrate 200 can be prevented from being oxidized. The alkali-earth metal diffuses into the photodiode 102B, forming a transistor and a photodiode. This can prevent adverse effects on the electrical characteristics of the board.

[0366] In addition, it is preferable that the surface of the base film 232 is highly flat. By using the photodiode 102B, defects in the formation of the semiconductor layer of the photodiode 102B can be prevented. It can be stopped.

[0367] The semiconductor layer of the photodiode 102A mainly absorbs visible light and rejects most of the infrared light. It is preferable to use a material that has a light-transmitting property. For example, amorphous silicon is used. It is possible.

[0368] The semiconductor layer of the photodiode 102B is made of a material that has the property of absorbing infrared light. For example, it is preferable to use crystalline silicon such as single crystal silicon or polycrystalline silicon. There can be.

[0369] In FIG. 14, the signal line 11 is a reset signal line (PR), and the signal line 12 is a charge storage signal line ( TX), signal line 13A is a selection signal line (SE), node 14 is a floating diffuser A digital (FD) node, signal line 15 is a photosensor reference signal line, and signal line 16 is a photosensor output signal line. This is the force signal line.

[0370] Note that the semiconductors used for the transistors 103, 104, and 105 It is preferable to appropriately select the body material depending on the purpose and application of the semiconductor device.

[0371] The insulating layer 240 may be a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film. A material having a light-transmitting property and an insulating property, such as an organic resin film, can be used for the insulating layer 240. It may be a single-layer structure or a laminated structure.

[0372] By providing the insulating layer 240, alkali metals such as Na and alkaline earth metals are prevented from entering the photoresist from the outside. It is possible to prevent the diffusion of the photoresist into the diode 102B and adversely affecting the characteristics.

[0373] The gate electrode 241, the gate electrode 242, and the conductive layer 108 are made of a conductive metal. Materials that can be used include molybdenum, titanium, chromium, tantalum, tungsten, and aluminium. Aluminum, copper, neodymium, scandium, and other metallic materials, or alloys containing these as the main components It is preferable to use a gold material. The layer 108 may have a single layer structure or a multilayer structure.

[0374] The insulating layer 243 may be a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film. A material having a light-transmitting property and an insulating property, such as an organic resin film, can be used. 243 may be of a single layer structure or a multilayer structure.

[0375] Conductive layer 244, conductive layer 245, conductive layer 246, conductive layer 247, conductive layer 254, and conductive layer 255 includes molybdenum, titanium, chromium, tantalum, tungsten, and aluminum. , copper, yttrium, and other metals, alloy materials containing these as main components, or indium oxide The conductive layer may be made of a material such as a metal oxide having electrical conductivity. It may be a single-layer structure or a laminated structure.

[0376] The insulating layer 233 may be a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film. A single layer or a laminated structure is formed using a material having light transmitting and insulating properties, such as an organic resin film. Note that the insulating layer 233 preferably has a flat surface.

[0377] The conductive layer 252 (pixel electrode) may be a conductive layer having light-transmitting properties. Using materials such as indium tin oxide with silicon (ITSO) and indium zinc oxide It can be formed by

[0378] Note that this embodiment mode can be appropriately combined with other embodiment modes described in this specification. . [Explanation of symbols]

[0379] 11 Signal Line 12 Signal Line 13 Signal Line 14 nodes 15 Signal Line 16 Signal Line 17 Signal Line 18 nodes 100 Light Sensor 101 Circuit 102 Photodiode 103 Transistor 104 Transistor 105 Transistor 106 Transistor 108 Conductive Layer 110 Optical Sensor Group 120 Optical Sensor Group 200 Transparent substrate 203 p-type semiconductor region 204 i-type semiconductor region 205 n-type semiconductor region 206 i-type semiconductor region 207 n-type semiconductor region 208 i-type semiconductor region 209 n-type semiconductor region 210 Conductive film 211 Conductive film 212 Conductive Film 213 Conductive Film 214 Conductive Film 215 Semiconductor Film 216 Semiconductor Film 217 Semiconductor Film 218 Conductive Film 219 Conductive Film 220 Conductive Film 221 Conductive Film 222 Conductive Film 223 Conductive Film 224 Conductive Film 225 Conductive Film 226 Conductive Film 227 Conductive Film 228 Gate insulating film 230 n-type semiconductor region 231 Light blocking layer 232 Base film 233 Insulating Layer 240 Insulating layer 241 Gate electrode 242 Gate electrode 243 Insulating Layer 244 Conductive Layer 245 Conductive Layer 246 Conductive Layer 247 Conductive Layer 248 p-type semiconductor region 249 i-type semiconductor region 250 active layer 251 Substrate 252 Conductive layer 253 n-type semiconductor region 254 Conductive layer 255 Conductive Layer 281 Insulating Film 282 Insulating Film 301 Pulse 302 Pulse 402 Photodiode 403 Transistor 404 Transistor 405 Transistor 411 Substrate 412 n-well 413 n-well 414 n-well 415 n-well 416 Field oxide 417 Gate insulating film 418 Gate insulating film 419 Gate insulating film Gate 420 420a Polycrystalline silicon layer 420b Silicide layer 423 Lightly doped drain region 424 Lightly doped drain region 425 Lightly doped drain region 426 Sidewall 427 Sidewall 428 Sidewall 430 Source Region 431 Source Region 432 Source Region 433 Drain Region 434 Drain Region 435 Drain Region 436 Interlayer insulating film 437 Interlayer insulating film 440 Source Wiring 441 Source wiring 442 Source wiring 443 Drain wiring 444 Drain wiring 445 Drain wiring 446 Electrode 447 Passivation Film 448 Interlayer insulating film 449 Electrode 450 electrodes 451 Electrode 452 Electrode 453 Electrode 454 Electrode 455 Interlayer insulating film 456 Pixel electrode 457 Transparent conductive film 458 Transparent conductive film 459 Organic EL layer 460 Photoelectric conversion layer 460i i-type semiconductor layer 460n n-type semiconductor layer 460p p-type semiconductor layer 461 Bulkhead 462 Transparent conductive film 463 Transparent Conductive Film 500 Semiconductor device 501 pixels 502 Light receiving part 503 Signal Processing Circuit 504 Light source 505 Irradiation control device 506 Detected object 507 Infrared Light 508 Reflected light 517 Visible light 518 visible light

Claims

1. a first photodiode, a second photodiode, a first storage transistor, a second storage transistor, a first amplifying transistor, a second amplifying transistor, a first output transistor, a second output transistor, a reference line, a first wiring, a first signal line, a second signal line, a first selection line, a second selection line, a first output line, a second output line, a first conductive layer, a second conductive layer, a third conductive layer, a fourth conductive layer, a fifth conductive layer, a sixth conductive layer, and a seventh conductive layer, a cathode of the first photodiode electrically connected to one of a source or a drain of the first storage transistor; a gate of the first storage transistor is electrically connected to the first signal line via the second conductive layer; the other of the source and the drain of the first storage transistor is electrically connected to the gate of the first amplification transistor via the third conductive layer; one of a source and a drain of the first amplifying transistor is electrically connected to the reference line; the other of the source and the drain of the first amplifying transistor is electrically connected to one of the source and the drain of the first output transistor; a gate of the first output transistor is electrically connected to the first selection line through the fourth conductive layer; the other of the source and the drain of the first output transistor is electrically connected to the first output line; a cathode of the second photodiode electrically connected to one of a source or a drain of the second storage transistor; a gate of the second storage transistor is electrically connected to the second signal line via the fifth conductive layer; the other of the source and the drain of the second storage transistor is electrically connected to the gate of the second amplification transistor via the sixth conductive layer; one of a source and a drain of the second amplifying transistor is electrically connected to the reference line; the other of the source and the drain of the second amplifying transistor is electrically connected to one of the source and the drain of the second output transistor; a gate of the second output transistor is electrically connected to the second selection line through the seventh conductive layer; the other of the source and the drain of the second output transistor is electrically connected to the second output line; the first conductive layer, the second conductive layer, the third conductive layer, the fourth conductive layer, the fifth conductive layer, the sixth conductive layer, and the seventh conductive layer comprise copper; the reference line, the first wiring, the first signal line, the second signal line, the first selection line, the second selection line, the first output line, and the second output line comprise copper; the first signal line, the second signal line, the reference line, the first selection line, and the second selection line are in contact with a first insulating layer and are disposed closer to a light receiving surface than the first insulating layer; the first conductive layer, the second conductive layer, the third conductive layer, the fourth conductive layer, the fifth conductive layer, the sixth conductive layer, and the seventh conductive layer are in contact with a second insulating layer and are disposed closer to a light receiving surface than the first insulating layer; a side surface of the first photodiode has a region in contact with a third insulating layer; the second insulating layer is disposed closer to the light receiving surface than the first insulating layer; the third insulating layer is disposed closer to the light receiving surface than the second insulating layer; In a plan view, a channel length direction of the first storage transistor is arranged in a first direction, In a plan view, a channel length direction of the first amplifying transistor is arranged in a second direction different from the first direction; In a plan view, a channel length direction of the first output transistor is arranged in the second direction, In a plan view, a channel length direction of the second storage transistor is arranged in the first direction, In a plan view, a channel length direction of the second amplifying transistor is arranged in the second direction, In a plan view, a channel length direction of the second output transistor is arranged in the second direction, In a plan view, the first signal line, the second signal line, the reference line, the first selection line, and the second selection line extend in a row direction, In a plan view, the first output line, the second output line, and the first wiring are extended in a column direction, the other of the first output line or the second output line is disposed between the first wiring and one of the first output line or the second output line in a plan view; the first wiring, the first output line, and the second output line are arranged to intersect with the first signal line, the second signal line, the reference line, the first selection line, and the second selection line in a plan view; the first wiring is electrically connected to an anode of the first photodiode and an anode of the second photodiode via the first conductive layer.

2. A display device comprising the imaging device according to claim 1.

Images