KR100800309B1 - Ultraviolet sensor, readout circuit for ultravilet sensor and image sensor including ultraviolet sensor - Google Patents

Abstract

The present invention relates to an image sensor including an ultraviolet sensor, a reading circuit for an ultraviolet sensor, and an ultraviolet sensor. More specifically, an image sensor capable of outputting not only image information but also intensity of ultraviolet rays, and which can be used in such an image sensor and silicon The invention relates to an ultraviolet sensor and a readout circuit for the ultraviolet sensor using the step.

According to an aspect of the present invention, there is provided a light emitting device including: a pixel array positioned inside a light control area and outputting an image signal corresponding to incident visible light; An ultraviolet sensor positioned inside the dimming area and outputting an ultraviolet signal corresponding to the intensity of the incident ultraviolet light; And a peripheral circuit unit configured to control the pixel array and to process and output the image signal and the ultraviolet signal.

Description

ULTRAVIOLET SENSOR, READOUT CIRCUIT FOR ULTRAVILET SENSOR AND IMAGE SENSOR INCLUDING ULTRAVIOLET SENSOR}

FIG. 1 is a view showing an image sensor according to an embodiment of the present invention. In particular, FIG. 1 illustrates an arrangement of an image sensor pixel and an ultraviolet sensor.

FIG. 2 is a diagram for explaining an example of specific wiring of the image sensor of FIG. 1.

3 is a diagram illustrating an example of an ultraviolet sensor and a reading circuit employed in the image sensor of FIG. 2.

4 is a signal diagram for describing an operation of the ultraviolet sensor and the reading circuit of FIG. 3.

FIG. 5 is a diagram illustrating a cross section of a polycrystalline silicon resistive ultraviolet sensor as an example of the ultraviolet sensor shown in FIG. 3.

FIG. 6 is a diagram for describing another example of specific wiring of the image sensor of FIG. 1.

FIG. 7 is a diagram illustrating an example of an ultraviolet sensor and a reading circuit employed in the image sensor of FIG. 6.

* Explanation of symbols in the main part of the drawing *

10: dimming area 20: pixel array

30 UV sensor 31 First polycrystalline silicon resistance

32: second polycrystalline silicon resistance 33: UV cut filter

34 substrate 35 insulating film

40: peripheral circuit portion 41: first shift register

42, 42`: sample and holder 43, 43`: second shift register

44, 44`: readout circuit

The present invention relates to an image sensor including an ultraviolet sensor, a reading circuit for an ultraviolet sensor, and an ultraviolet sensor. More specifically, an image sensor capable of outputting not only image information but also intensity of ultraviolet rays, and which can be used in such an image sensor and silicon The invention relates to an ultraviolet sensor and a readout circuit for the ultraviolet sensor using the step.

In recent years, with the widespread use of digital cameras, digital camcorders, and mobile phones including their functions, image sensors are rapidly developing. An image sensor is a semiconductor device that converts an optical image into an electrical signal. The image sensor may be classified into a charge coupled device (CCD) image sensor and a complementary metal oxide semiconductor (CMOS) type image sensor. . Among them, the CCD-type image sensor moves electrons generated by light to the output unit using a CCD as it is, and the CMOS-type image sensor converts electrons generated by light to a voltage in a pixel and then to the output unit. . For this reason, the CCD image sensor is mainly used in high-quality video equipment having high image quality and high sensitivity, but there is a problem in that single chip with a CMOS circuit is not easy and power consumption is high. On the contrary, the CMOS image sensor generates a lot of noise and has low sensitivity, but has advantages in that it is easy to single chip with a CMOS circuit, has low power consumption, and can be manufactured using a general CMOS process.

On the other hand, ultraviolet rays contained in sunlight, etc. may penetrate the surface of the skin, cause burns, increase the frequency of skin cancer and cataracts, and may adversely affect health, and thus, the intensity of ultraviolet rays needs to be measured. Conventional technology related to such an ultraviolet sensor is disclosed in Korea Patent Publication No. 10-2005-0026728 (name of the invention: UV exposure warning method of the mobile communication terminal). This document describes the intensity of UV light using an analog-to-digital converter (hereinafter simply referred to as an ADC) that converts an analog sensor value output from an ultraviolet sensor and an ultraviolet sensor mounted in a mobile communication terminal into a digital signal. Techniques for measuring are disclosed. However, according to the prior art, since the mobile communication terminal must have an ultraviolet sensor and an ADC mounted separately from the image sensor, there is a problem that additional component cost, installation cost, and power consumption occur. In addition, there is a problem that it is not easy to secure a space for adding an ultraviolet sensor and an ADC inside a recent miniaturized mobile communication terminal.

Therefore, the technical problem to be achieved by the present invention is to solve the above problems, the image sensor that can output not only the image information, but also the intensity of the ultraviolet ray, and the ultraviolet sensor and the readout circuit for the ultraviolet sensor that can be used in such an image sensor To provide.

In addition, the technical problem to be achieved by the present invention is mainly manufactured using the conventional GaN-based compound semiconductor is compatible with the process of the silicon image sensor rather than the ultraviolet sensor that is not easy to integrate into the silicon, the production cost can be reduced The present invention provides an ultraviolet sensor and a readout circuit for the ultraviolet sensor and an image sensor including the same.

In addition, the technical problem to be achieved by the present invention is that the image sensor and the ultraviolet sensor is integrated together, there is no need to separately provide a region for receiving the light corresponding to the image and the region for receiving the light corresponding to the ultraviolet light, space utilization aspect To provide an efficient image sensor and a readout circuit for an ultraviolet sensor and an ultraviolet sensor that can be used in such an image sensor.

In addition, the technical problem to be achieved by the present invention is to integrate the image sensor and the ultraviolet sensor together, inexpensive, miniaturized, low power consumption image sensor and the ultraviolet circuit and the readout circuit for the ultraviolet sensor that can be used for such an image sensor To provide.

In addition, the technical problem to be achieved by the present invention is not only the design of the bill, but also can detect ultraviolet rays, image sensor that can be easily applied to the counterfeit discriminator and the like and the ultraviolet sensor and the readout circuit for the ultraviolet sensor that can be used in such an image sensor To provide.

In addition, the technical problem to be achieved by the present invention is to use a blanking time, an image sensor that does not require a separate wiring for the output of the ultraviolet intensity, and a reading circuit for the ultraviolet sensor that can be used in such an image sensor To provide.

In addition, the technical problem to be achieved by the present invention is to provide a readout circuit for the ultraviolet sensor that can be easily implemented.

As a technical means for achieving the above object, a first aspect of the present invention is a pixel array which is located inside the dimming area, and outputs an image signal corresponding to the incident visible light; An ultraviolet sensor positioned inside the dimming area and outputting an ultraviolet signal corresponding to the intensity of the incident ultraviolet light; And a peripheral circuit unit configured to control the pixel array and to process and output the image signal and the ultraviolet signal.

A second aspect of the present invention is a UV filter for blocking ultraviolet light from incident light; A first polycrystalline silicon resistor receiving light including ultraviolet rays; And a second polycrystalline silicon resistor receiving the light from which the ultraviolet light passing through the ultraviolet blocking filter is removed.

According to a third aspect of the present invention, there is provided a semiconductor device comprising: a first transistor configured to reset, according to a control signal, a first node receiving a current corresponding to an intensity of light including ultraviolet rays from an ultraviolet sensor; A second transistor configured to reset, according to the control signal, a second node that receives a current corresponding to the intensity of light from which the ultraviolet light is removed from the ultraviolet sensor; A first comparator outputting a result of comparing the voltage of the first node with a reference voltage; A second comparator configured to output a result of comparing the voltage of the second node with the reference voltage; A counter for performing a reset or counting according to the output of the first comparator; And a register configured to latch a value of the counter according to the output of the second comparator and output the digital signal corresponding to the intensity of ultraviolet light.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various forms, the scope of the present invention should not be construed in a way that is limited by the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

FIG. 1 is a view showing an image sensor according to an embodiment of the present invention. In particular, FIG. 1 illustrates an arrangement of an image sensor pixel and an ultraviolet sensor. Referring to FIG. 1, the image sensor includes a pixel array 20 for an image sensor, an ultraviolet sensor 30, and a peripheral circuit unit 40.

Among them, the pixel array 20 and the ultraviolet sensor 30 are positioned in the light receiving area 10, that is, a region receiving light passing through an optical system (not shown). Since the peripheral circuit unit 40 does not need to receive light passing through the optical system, the peripheral circuit unit 40 may be located inside the dimming area 10, or may be located outside the dimming area 10, and the dimming area 10 as shown in the drawing. It may be located inside and outside the.

In the image sensor according to the exemplary embodiment of the present invention, as shown in the figure, the ultraviolet light sensor 30 is disposed by utilizing an area in which the pixel array 20 is not disposed in the light control area 10, thereby receiving ultraviolet light input. Since there is no need to provide a separate area, there is an advantage that the space utilization is improved. In addition, since the pixel array 20 and the ultraviolet sensor 30 receive light passing through the same optical system, the pixel array 20 and the ultraviolet sensor 30 do not need to have a separate optical system.

FIG. 2 is a diagram for explaining an example of specific wiring of the image sensor of FIG. 1.

Referring to FIG. 2, the pixel array 20 outputs an image signal corresponding to incident visible light. The pixel array 20 may be a pixel array for a CCD image sensor, but it is preferable that the pixel array 20 is a pixel array for a CMOS image sensor that can be easily chipped with the peripheral circuit unit 40.

The ultraviolet sensor 30 outputs an ultraviolet signal corresponding to the incident ultraviolet light. The ultraviolet sensor 30 may be an ultraviolet sensor using GaN-based compound semiconductors or any other type of ultraviolet sensor. However, the UV sensor 30 may be described later, which is compatible with the process of the silicon image sensor. It is preferable that it is a sensor. The ultraviolet signal may include, for example, a current corresponding to the intensity of light including ultraviolet rays and a current corresponding to the intensity of light from which ultraviolet rays are removed.

The peripheral circuit portion 40 includes a first shift register 41, a sample and holder 42, a second shift register 43, and a read circuit 44. The first shift register 41, the sample and holder 42, and the second shift register 43 are already well developed and well known, and the first shift register 41, the sample and holder 42, and the second shift register are well known. As 43, any circuits may be used.

The first shift register 41 is also referred to as a row decoder or a row driver, and outputs an image signal to the sample and the holder 42 among a plurality of rows included in the pixel array 20. To select sequentially. Pixels (not shown) included in the selected row output an image signal to the sample and the holder 42.

The sample and holder 42 sample the image signal output from the pixel array 20, and then sequentially output the sampled image signal in accordance with selection by the second shift register 43. The sample and holder 42 may output the sampled analog image signal as it is, or may convert the sampled signal into a digital signal and output the same. The sample and holder 42 may comprise a correlated double sampling circuit (hereinafter simply referred to as a CDS circuit). The sample and holder 42 may be output in an image signal unit corresponding to one pixel or in an image signal unit corresponding to a plurality of pixels.

The second shift register 43 is also called a column decoder or column driver, and controls the sample and holder 42 so that the image signals sampled by the sample and holder 42 are sequentially output. It performs the function.

The readout circuit 44 amplifies and outputs the ultraviolet signal output from the ultraviolet sensor 30, or converts the ultraviolet signal output from the ultraviolet sensor 30 into a digital signal and outputs the digital signal.

The image sensor represented in the figure is implemented by the ultraviolet sensor 30 and the readout circuit 44 independently of the conventional image sensors 20, 41, 42, and 43, and thus, if only the ultraviolet intensity is desired, 30 and only the read circuit 44 and the remaining (20, 41, 42, 43) do not need to drive, there is an advantage in terms of power consumption. In addition, by adding only the ultraviolet sensor 30 and the readout circuit 44 to the conventional image sensor 20, 41, 42, 43, by implementing an image sensor that can also detect the intensity of ultraviolet rays, the conventional image sensor 20 , 41, 42, and 43) do not require design changes and can be implemented quickly.

3 is a diagram illustrating an example of an ultraviolet sensor and a reading circuit employed in the image sensor of FIG. 2.

Referring to FIG. 3, the ultraviolet sensor 30 includes a first polycrystalline silicon resistor 31, a second polycrystalline silicon resistor 32, and an ultraviolet blocking filter 33.

The first and second polycrystalline silicon resistors 31 and 32 have a lower resistance value when the intensity of incident light increases, and a higher resistance value when the intensity of incident light decreases. Since the first and second polycrystalline silicon resistors 31 and 32 should have a high resistance value when no light is incident, they are preferably resistors using undoped polycrystalline silicon.

The ultraviolet blocking filter 33 is a filter which blocks ultraviolet rays among incident light. As the UV blocking filter 33, for example, a nitride film (Si ₃ N ₄ ) suitable for a silicon process may be used. In order to block ultraviolet rays, the refractive index of the nitride film is preferably 2.0 or more. In addition, as the UV blocking filter 33, PMMA (polymethylmethacrylate) having UV blocking ability may be used. In this case, the PMMA may be positioned in an optical system (not shown) such that ultraviolet rays are incident on the first polycrystalline silicon resistor 31 and ultraviolet rays are not incident on the second polycrystalline silicon resistor 32.

In the ultraviolet sensor 30, light including ultraviolet rays is incident on the first polycrystalline silicon resistor 31, and light from which ultraviolet rays are removed is incident on the second polycrystalline silicon resistor 32. A difference in resistance occurs in the silicon resistors 31 and 32. Since the resistance difference is a value corresponding to the intensity of ultraviolet rays, the resistance difference is detected, digitally converted, and output by the reading circuit 44.

The read circuit 44 includes first and second transistors M1 and M2, first and second comparators CMP1 and CMP2, a counter CNT, and a register REG. The read circuit 44 may further include first and second amplifiers AMP1 and AMP2.

The first transistor M1 resets the first node N1 to the power supply voltage VDD according to the control signal VRS, and the second transistor M2 resets the second node N2 to the control signal VRS. Therefore, reset the power supply voltage (VDD). The first node N1 receives a current corresponding to the intensity of light including ultraviolet rays from the ultraviolet sensor 30, and the second node N2 corresponds to the intensity of light from which the ultraviolet rays are removed from the ultraviolet sensor 30. It is a node that receives current.

The first and second amplifiers AMP1 and AMP2 amplify the voltages of the first and second nodes N1 and N2, respectively.

The first and second comparators CMP1 and CMP2 output ROUT and SOUT as a result of comparing the reference voltage VREF with the output voltages VR and VS of the first and second amplifiers AMP1 and AMP2, respectively. Perform the function. If the first and second amplifiers AMP1 and AMP2 are not used, the first and second comparators CMP1 and CMP2 are connected to the reference voltage VREF and the first and second nodes N1 and N2. Compare the voltages respectively.

The counter CNT receives the output ROUT of the first comparator CMP1 as a reset terminal and performs a reset or counting according to the output ROUT of the first comparator CMP1. In the example represented in the drawing, the counter CNT maintains the reset state in a period in which the output voltage VR of the first amplifier AMP1 is greater than the reference voltage VREF, and then outputs the first amplifier AMP1. Counting is performed in a period in which the voltage VR is smaller than the reference voltage VREF.

The register REG performs a function of latching and outputting the output of the counter according to the output SOUT of the second comparator CMP2. In the example represented in the drawing, the register REG latches and outputs the counter CNT output value at the moment when the output voltage VS of the second amplifier AMP2 changes smaller than the reference voltage VREF. The output of the register REG is a digital signal corresponding to the intensity of the ultraviolet rays.

The readout circuit 44 may receive an ultraviolet signal output from the ultraviolet sensor 30 and output a digital signal corresponding to the intensity of the ultraviolet light by using only a simple circuit as illustrated in the figure.

4 is a signal diagram for describing an operation of the ultraviolet sensor and the reading circuit of FIG. 3.

Referring to FIGS. 3 and 4, first, the voltages of the first and second nodes N1 and N2 are converted to the power supply voltage VDD by the control signals VRS applied to the gates of the first and second transistors M1 and M2. Is reset to).

Thereafter, the voltage levels of the first and second nodes N1 and N2 are lowered by the current flowing through the first and second polycrystalline silicon resistors 31 and 32, respectively. Since light including ultraviolet rays enters the first polycrystalline silicon resistor 31 and the resistance thereof is low, the voltage level of the first node N1 decreases relatively quickly. On the contrary, the light from which ultraviolet rays have been removed is incident on the second polycrystalline silicon resistor 32, and the resistance value thereof is high, so that the voltage level of the second node N2 decreases relatively slowly.

Therefore, the output voltage VR of the first amplifier AMP1 quickly becomes lower than the reference voltage VREF, and the output voltage VS of the second amplifier AMP2 slowly becomes lower than the reference voltage VREF, so that the first comparator The output ROUT of CMP1 is changed to a high level before the output SOUT of the second comparator CMP2. The difference between the time when the output ROUT of the first comparator CMP1 and the output SOUT of the second comparator CMP2 is changed to a high level has a value corresponding to the intensity of ultraviolet light. More specifically, when the intensity of the ultraviolet light is weak, since the output voltage VR of the first amplifier AMP1 and the output voltage VS of the second amplifier AMP2 are similarly low, the time difference will be small, and the intensity of the ultraviolet light is strong. In this case, since the output voltage VR of the first amplifier is lowered much faster than the output voltage VS of the second amplifier, the time difference will be large. Thus, the time difference has a value corresponding to the intensity of ultraviolet light.

The time difference is calculated and output by the counter CNT and the register REG that receive the outputs ROUT and SOUR of the first and second comparators CMP1 and CMP2.

The read circuit 44 shown in the drawing operates in this way to output a digital signal corresponding to the intensity of the ultraviolet rays.

FIG. 5 is a diagram illustrating a cross section of a polycrystalline silicon resistive ultraviolet sensor as an example of the ultraviolet sensor shown in FIG. 3.

Referring to FIG. 5, an ultraviolet sensor is formed on an insulating film 35 formed on a substrate 34, first and second polycrystalline silicon resistors 31 and 32 formed on the insulating film 35, and a second polycrystalline silicon resistor 32. The formed UV blocking filter 33 is included.

Substrate 34 is preferably a silicon substrate. The insulating film 35 may be, for example, an oxide film SiO ₂ . The first and second polycrystalline silicon resistors 31 and 32 are preferably made of undoped polycrystalline silicon. The ultraviolet cut filter 33 is preferably a nitride film SI ₃ N ₄ .

Visible light (RGB) and ultraviolet light (UV) are incident on the first polycrystalline silicon resistor 31, but only visible light (RGB) is incident on the second polycrystalline silicon resistor 32. Therefore, since the difference between the resistance values of the first polycrystalline silicon resistor 31 and the second polycrystalline silicon resistor 32 has a value corresponding to the intensity of the ultraviolet light, the element shown in the figure operates as an ultraviolet sensor.

Since the insulating film 35, the polycrystalline silicon resistors 31 and 32, and the UV cut filter 33 shown in the drawing can be easily manufactured by using a general silicon process, the UV sensor shown in the drawing is a silicon process and a CMOS image. It has the advantage of being compatible with sensors.

FIG. 6 is a diagram for describing another example of specific wiring of the image sensor of FIG. 1.

In FIG. 6, the pixel array 20, the ultraviolet sensor 30, and the first shift register 41 are not different from the pixel array 20, the ultraviolet sensor 30, and the first shift register 41 of FIG. 2. For convenience of description, description thereof will be omitted. The pixel array 20 includes a plurality of pixels 21.

The readout circuit 44 'operates according to a signal output from the first shift register 41, receives an ultraviolet signal from the ultraviolet sensor 30, and is a voltage corresponding to the intensity of light including ultraviolet rays. The second voltage, which is a voltage corresponding to the removed light, is output to the sample and the holder 42 '. The read circuit 44 ′ may receive a signal transferred from the first shift register 41 to any one row of the pixel array 20 as shown in the drawing, and unlike the drawing, the read circuit 44 ′ is not transmitted to the pixel array 20. May be input from the first shift register 41.

Like the sample and holder 42 shown in FIG. 2, the sample and holder 42 ′ sample an image signal output from the pixel array 20, and then convert a signal corresponding to the sampled image signal into a second shift register ( 43 ') to output sequentially. In addition, the sample and holder 42 'sample the first and second voltages output from the readout circuit 44', and output a signal corresponding to the sampled first and second voltages to the second shift register 43 '. Output according to the selection. The signal corresponding to the sampled first and second voltages may be, for example, a signal corresponding to a difference between the first and second voltages.

Like the second shift register 43 shown in FIG. 2, the second shift register 43 ′ functions to control the sample and the holder 42 ′ so that signals corresponding to the sampled image signals are sequentially output. . In addition, the second shift register 43 ′ controls the sample and the holder 42 ′ so that signals corresponding to the sampled first and second voltages are output. At this time, the second shift register 43 'may output the signal corresponding to the sampled first and second voltages as well as the signal corresponding to the sampled image signal using the same wiring. ) May control the sample and holder 42 ′ such that signals corresponding to the sampled first and second voltages are output in a period in which no signal corresponding to the sampled image signal is output. That is, the second shift register 43 ′ may control the sample and the holder 43 ′ such that a signal corresponding to the sampled image signal and a signal corresponding to the sampled first and second voltages are multiplexed and output. In one example, the second shift register 43 ′ may control the sample and the holder 42 ′ so that signals corresponding to the sampled first and second voltages are output at a vertical blanking time.

Since the image sensor shown in the figure also outputs a signal corresponding to the intensity of the ultraviolet rays by using a wire to which a conventional image signal is output, it does not require an additional wiring for outputting a signal corresponding to the intensity of the ultraviolet rays. Have

FIG. 7 is a diagram illustrating an example of an ultraviolet sensor and a reading circuit employed in the image sensor of FIG. 6.

In FIG. 7, since the ultraviolet sensor 30 is not different from the ultraviolet sensor 30 of FIG. 3, description thereof will be omitted for convenience of description.

The readout circuit 44 ′ is connected to the first and second polycrystalline silicon resistors 31, 32 of the ultraviolet sensor 30, and from the first shift register 41, the first and second control signals CR, CX. The first voltage VR corresponding to the intensity of light including ultraviolet rays and the second voltage VS corresponding to the intensity of light from which ultraviolet rays are removed are output to the sample and holder 42 ′. The read circuit 44 ′ includes the first to sixth transistors M1 to M6.

The first transistor M1 resets the first node N1 to the power supply voltage VDD according to the first control signal CR, and the second transistor M2 resets the second node N2 to the first control signal. Reset to the power supply voltage VDD in accordance with (CR). The first node N1 receives a current corresponding to the intensity of light including ultraviolet rays from the ultraviolet sensor 30, and the second node N2 corresponds to the intensity of light from which the ultraviolet rays are removed from the ultraviolet sensor 30. It is a node that receives current.

The third and fourth transistors M3 and M4 serve as source follower buffer amplifiers, respectively, and amplify and output voltages of the first and second nodes N1 and N2. The voltage gain of the third and fourth transistors M3 and M4 may be 1 due to the characteristics of the source follower buffer amplifier.

The fifth and sixth transistors M5 and M6 output a voltage output from the third and fourth transistors M3 and M4 to the sample and the holder 42 ′ according to the second control signal CX, respectively. To perform. A voltage output from the fifth and sixth transistors M5 and M6 to the sample and the holder 42 ′ respectively corresponds to the first voltage VR corresponding to the intensity of light including ultraviolet rays and the intensity of light from which the ultraviolet rays are removed. 2 voltage (VS).

As shown in the drawing, the readout circuit 44` receives a signal output from the ultraviolet sensor 30 by using only a simple circuit and removes the first voltage VR and the ultraviolet light corresponding to the light including the ultraviolet light. The second voltage VS corresponding to the light may be output to the sample and the holder 42 ′.

As can be easily seen from reviewing the drawings, the first, third and fifth transistors M1, M3, and M5 connected to the first polycrystalline silicon resistor 31 are the same as the pixel circuits of a general CMOS image sensor. As will be apparent to those skilled in the art, a detailed description of the operation is omitted for convenience of description. In addition, as the pixel circuit of the general CMOS image sensor may be variously modified, a portion of the readout circuit 44 ′ connected to the first polycrystalline silicon resistor 31 may also be variously modified. In addition, the second, fourth and sixth transistors M2, M4, and M6 connected to the second polycrystalline silicon resistor 32 may also have the first, third and fifth transistors M1 connected to the first polycrystalline silicon resistor 31. , M3 and M5), so detailed description thereof will be omitted.

The image sensor according to the present invention has an advantage of outputting not only image information but also ultraviolet ray intensity.

In addition, the image sensor and the ultraviolet sensor and the readout circuit that can be used in the image sensor according to the present invention is compatible with the process of the silicon image sensor, there is an advantage that the manufacturing cost can be reduced.

In addition, since the image sensor according to the present invention is integrated with a general image sensor and an ultraviolet sensor, there is no need to separately provide a region for receiving light corresponding to an image and a region for receiving light corresponding to ultraviolet rays, and thus, the space utilization aspect. Has the advantage of being efficient.

In addition, the image sensor according to the present invention has the advantage of being inexpensive, compact, and low power consumption by integrating a general image sensor and the ultraviolet sensor together.

In addition, the image sensor according to the present invention has the advantage that it can be easily applied to the counterfeit discriminator because it can detect not only the bill of the bill, but also ultraviolet rays.

In addition, the image sensor according to the present invention has an advantage of not requiring a separate wiring for outputting a signal corresponding to ultraviolet light intensity by using a blanking time.

In addition, the readout circuit according to the present invention has the advantage that it can be simply implemented.

Claims (19)

A pixel array positioned inside the dimming area and outputting an image signal corresponding to incident visible light; An ultraviolet sensor positioned inside the dimming area and outputting an ultraviolet signal including a current corresponding to the intensity of incident ultraviolet light and a current corresponding to the intensity of light including the ultraviolet ray; and a current corresponding to the intensity of the light from which the ultraviolet light is removed; And And a peripheral circuit unit configured to control the pixel array and to process and output the image signal and the ultraviolet signal. The method of claim 1, Further includes an optical system, The dimming area is an image sensor, characterized in that the area receiving the light passing from the optical system. delete According to claim 1, The ultraviolet sensor is An ultraviolet cut filter for blocking ultraviolet rays from incident light; A first polycrystalline silicon resistor receiving light including ultraviolet rays; And And a second polycrystalline silicon resistor receiving the light from which the ultraviolet light passing through the ultraviolet blocking filter is removed. The method of claim 4, wherein The UV cut filter is an image sensor consisting of PMMA or nitride film The method of claim 4, wherein And the first and second polycrystalline silicon resistors are made of undoped polycrystalline silicon. According to claim 1, The peripheral circuit portion A first shift register sequentially selecting rows included in the pixel array; A sample and holder for sampling the image signal output from the row selected by the first shift register and then outputting a signal corresponding to the sampled image signal; A second shift register configured to control the sample and the holder such that signals corresponding to the sampled image signal are sequentially output; And And a readout circuit configured to receive the ultraviolet light signal and output a digital signal corresponding to the intensity of the ultraviolet light. The method of claim 7, wherein The readout circuit is A first transistor configured to reset a first node receiving a current corresponding to the intensity of light including ultraviolet rays from the ultraviolet sensor according to a control signal; A second transistor configured to reset, according to the control signal, a second node that receives a current corresponding to the intensity of light from which the ultraviolet light is removed from the ultraviolet sensor; A first comparator outputting a result of comparing the voltage of the first node with a reference voltage; A second comparator configured to output a result of comparing the voltage of the second node with the reference voltage; A counter for performing a reset or counting according to the output of the first comparator; And And a register configured to latch a value of the counter according to the output of the second comparator and output the digital signal corresponding to the intensity of the ultraviolet light. According to claim 1, The peripheral circuit portion A first shift register sequentially selecting rows included in the pixel array; A readout circuit controlled by the first shift register and configured to receive the ultraviolet signal and output a first voltage corresponding to the intensity of light including ultraviolet rays and a second voltage corresponding to the intensity of light from which ultraviolet rays are removed; The image signal output from the row selected by the first shift register, a signal corresponding to the sampled image signal after sampling the first and second voltages, and a signal corresponding to the sampled first and second voltages. A sample and a holder to output the; And And a second shift register configured to control the sample and the holder such that a signal corresponding to the sampled image signal and a signal corresponding to the sampled first and second voltages are multiplexed and output. The method of claim 9, And the second shift register controls the sample and the holder such that signals corresponding to the sampled first and second voltages are output at vertical retrace time. The method of claim 9, The readout circuit is A first transistor configured to reset a first node receiving a current corresponding to the intensity of light including ultraviolet rays from the ultraviolet sensor according to a first control signal; A second transistor configured to reset, according to the first control signal, a second node that receives a current corresponding to the intensity of light from which the ultraviolet light is removed from the ultraviolet sensor; A third transistor that amplifies the voltage at the first node; A fourth transistor for amplifying the voltage at the second node; A fifth transistor configured to output the amplified voltage of the first node as the first voltage according to a second control signal; And And a sixth transistor configured to output the amplified voltage of the second node as the second voltage according to the second control signal. The method of claim 11, wherein And the third and fourth transistors operate as source follower buffer amplifiers. An ultraviolet cut filter for blocking ultraviolet rays from incident light; A first polycrystalline silicon resistor receiving the incident light; And And a second polycrystalline silicon resistor receiving the light from which the ultraviolet light is removed by the ultraviolet blocking filter. The difference between the resistance values of the first polycrystalline silicon resistor and the second polycrystalline silicon resistor corresponds to the intensity of the ultraviolet light. The method of claim 13, The ultraviolet filter is an ultraviolet sensor consisting of PMMA or nitride film. The method of claim 13, And the first and second polycrystalline silicon resistors are made of undoped polycrystalline silicon. The method of claim 13, Further comprising an insulating film formed on the substrate, The first and second polycrystalline silicon resistors are formed on the insulating film, And the ultraviolet cut filter is formed on the second polycrystalline silicon resistor. The method of claim 16, The substrate is a silicon substrate, The insulating film is an ultraviolet sensor. A first transistor configured to reset, according to a control signal, a first node receiving a current corresponding to the intensity of light including ultraviolet rays from the ultraviolet sensor; A second transistor configured to reset, according to the control signal, a second node that receives a current corresponding to the intensity of light from which the ultraviolet light is removed from the ultraviolet sensor; A first comparator outputting a result of comparing the voltage of the first node with a reference voltage; A second comparator configured to output a result of comparing the voltage of the second node with the reference voltage; A counter for performing a reset or counting according to the output of the first comparator; And And a register configured to latch a value of the counter according to the output of the second comparator and output the digital signal corresponding to the intensity of ultraviolet light. The method of claim 18, A first amplifier amplifying the voltage of the first node and outputting the amplified voltage to the first comparator; And A second amplifier for amplifying the voltage of the second node and outputs to the second comparator, The first comparator outputs a result of comparing the amplified voltage of the first node with the reference voltage, And the second comparator outputs a result of comparing the amplified voltage of the second node with the reference voltage.

Images