TDI image sensor capable of adjusting exposure time and inspection system including the same

Abstract

The present application discloses a TDI image sensor capable of adjusting an exposure time and an inspection system including the same. The TDI sensor capable of controlling an exposure according to the present disclosure includes: a pixel unit including a plurality of row sensors; a light blocking unit that blocks light from being incident on some of the plurality of row sensors; and a scan controller that generates an exposure control signal based on an external row trigger signal, generates an internal row trigger signal based on the external row trigger signal and the exposure control signal, and controls the movement of charges of the plurality of row sensors based on the internal row trigger signal.

Description

Technical Field

[0001] The present disclosure relates to a time delay integration (TDI) image sensor, and more particularly, to a TDI image sensor capable of adjusting an exposure time and an inspection system including the TDI image sensor. Background Art

[0002] As production facilities become mass-produced, automated, and precise, functions relying on the human eye or various sensors are being replaced by image sensors. As an example of a semiconductor device mainly used for an image sensor, there is a charge coupled device (CCD).

[0003] A charge coupled device (hereinafter simply referred to as CCD) refers to a device that transfers charges from one device to another adjacent device. An image sensor using such a CCD has a structure that converts changes in a large amount of charges caused by a certain amount of light into an electrical signal. An image sensor using a CCD includes an output unit configured by a unit region in which charges are accumulated and a shift register that sequentially transfers the accumulated charges.

[0004] Scanning methods of an image sensor include a region scanning method, a line scanning method, and a time delay integration (TDI) line scanning method.

[0005] In an image sensor using the TDI line scanning method, a plurality of line sensors are arranged in a scanning direction to transfer charges accumulated in the CCDs of each line to the CCDs of the next line in synchronization with the movement of a scanning object. By repeating this process for the sensors to the last line, the charges are accumulated and then output to obtain an image.

[0006] Reference Figure 12 , a TDI line sensor accumulates charges in a CCD sensor by converting light from a target for each line into electrical energy and moving the accumulated charges in a scanning direction. In Figure 12 's integration step, the charges accumulated in the TDI line sensor are repeatedly accumulated by being shifted downward according to the moving speed of the target for each line, and the sensed charges are amplified and processed by a readout register at the end and then output. Since the sensed charges are accumulated through a time delay integration step, the image quality can be further enhanced. The advantage of a TDI line sensor is that by performing the process of sensing and accumulating the sensed charges multiple times, a clear image can be obtained even under dim illumination.

[0007] It is necessary to expand the brightness range by making the bright part of an image obtained from an image sensor using the TDI line scanning method brighter and the dark part darker, so that the image becomes more similar to what is seen by the human eye. Summary of the Invention

[0008] An object of an exemplary embodiment of the present disclosure is to provide a TDI image sensor capable of adjusting an exposure time to obtain a clearer image and an inspection system including the TDI image sensor.

[0009] In addition, an object of an exemplary embodiment of the present disclosure is to provide a TDI image sensor and an inspection system including the TDI image sensor, the TDI image sensor being capable of adjusting an exposure time to obtain a short-exposure (or low-brightness) image and a long-exposure (or high-brightness) image for the same object to be captured and combining them to extend a dynamic range of an image so as to clearly show all details of a bright part and a dim part in an image.

[0010] The object of the present disclosure is not limited to the above object, and other objects and advantages of the present disclosure not mentioned above can be understood from the following description and become more obvious from the exemplary embodiments of the present disclosure. In addition, it should be understood that the objects and advantages of the present disclosure can be embodied by various methods and combinations thereof in the claims.

[0011] To achieve the above object, according to one aspect of the present disclosure, there is provided a TDI image sensor capable of adjusting an exposure time, including: a pixel unit including a plurality of row sensors; a light-blocking unit configured to block light from being incident on some of the plurality of row sensors; and a scan controller configured to generate an exposure control signal based on an external row trigger signal, generate an internal row trigger signal based on the external row trigger signal and the exposure control signal, and control movement of charges of the plurality of row sensors based on the internal row trigger signal.

[0012] According to another aspect of the present disclosure, there is provided a TDI image sensor capable of adjusting an exposure time and an inspection system including the TDI image sensor, the TDI image sensor including: a pixel unit including a plurality of row sensors, where light incident on a part of each row sensor is blocked by a light-blocking unit and the remaining part of each row sensor is exposed; a scan controller configured to control exposure of the exposed part of the row sensors with different exposure times to generate a sensing result for a first exposure time and a sensing result for a second exposure time; and an output unit configured to generate an image based on the sensing result for the first exposure time and the sensing result for the second exposure time.

[0013] According to an exemplary embodiment of the present disclosure, a TDI image sensor capable of adjusting an exposure time and an inspection system including the TDI image sensor can obtain a clearer TDI image, so as to maximize an applicable field of the TDI image sensor. Brief Description of the Drawings

[0014] Figure 1 is a view showing a schematic configuration of a TDI image sensor capable of adjusting an exposure time and an inspection system including the TDI image sensor according to an exemplary embodiment of the present disclosure;

[0015] Figure 2 is a view showing an exemplary embodiment of the present disclosure Figure 1 of the configuration of a pixel unit;

[0016] Figures 3A to 3D is a view for explaining the configuration of a pixel unit, a light shielding unit, and a microlens combined according to an exemplary embodiment of the present disclosure; Figure 1 of the pixel unit, the light shielding unit, and the microlens;

[0017] Figure 4 is a view showing an exemplary embodiment of the present disclosure Figure 1 of a schematic configuration of a scan controller;

[0018] Figure 5 is a view showing an exemplary embodiment of the present disclosure Figure 4 of a schematic configuration of an exposure control signal generator;

[0019] Figure 6 is a view for explaining Figure 5 the operation of the exposure control signal generator;

[0020] Figure 7 is a view showing a schematic configuration of a scan controller according to another exemplary embodiment of the present disclosure;

[0021] Figure 8 is a view showing a schematic configuration of an exposure control signal generator according to another exemplary embodiment of the present disclosure;

[0022] Figure 9 is a view for explaining the operation of the exposure control signal generator according to another exemplary embodiment of the present disclosure;

[0023] Figure 10 is a view for explaining the operation of a TDI image sensor capable of adjusting an exposure time and an inspection system including the TDI image sensor according to an exemplary embodiment of the present disclosure;

[0024] Figure 11 is a view for explaining a control method of a TDI image sensor according to an exemplary embodiment of the present disclosure; and

[0025] Figure 12 is a view for explaining the scanning principle of a conventional TDI image sensor. Detailed Description

[0026] The above objects, features, and advantages will be described in detail with reference to the accompanying drawings, and thus those of ordinary skill in the art can easily implement the technical spirit of the present disclosure. When it is determined that a detailed description of the known art related to the present disclosure may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present disclosure will be described with reference to the accompanying drawings. In the drawings, like reference numerals denote like components.

[0027] As described above, the TDI image sensor capable of adjusting the exposure time and the inspection system including the TDI image sensor according to an exemplary embodiment of the present disclosure are technologies that expand the dynamic range of the TDI image so that the image obtained from the TDI image sensor is presented such that bright portions are brighter and dark portions are darker to obtain a clearer image.

[0028] The TDI image sensor capable of adjusting the exposure time according to an exemplary embodiment of the present disclosure and the inspection system including the TDI image sensor for obtaining a clearer image acquire a long-exposure image and a short-exposure image for one object to be captured through one scan under the same lighting conditions and combine the two images using high dynamic range (HDR) technology to present the details of the bright and dark portions of a combined image more clearly.

[0029] At this time, the HDR technology is a technology that acquires a short-exposure image and a long-exposure image for the same object to be captured and combines them so as to clearly present both the bright and dark portions in one image, thereby expanding the dynamic range of the image.

[0030] In the present disclosure, HDR is mentioned as an example of a signal processing technology for generating high-quality images. However, the exemplary embodiments are provided for easy understanding, and it should be understood that any signal processing technology for generating high-quality images using long-exposure image data and short-exposure image data obtained from the same object may also be used.

[0031] Configurations and methods for acquiring a short-exposure image and a long-exposure image in a TDI image sensor capable of adjusting the exposure time and an inspection system including the same according to an exemplary embodiment of the present disclosure are described below.

[0032] Figure 1 It is a view showing a schematic configuration of a TDI image sensor capable of adjusting the exposure time and an inspection system including the TDI image sensor according to an exemplary embodiment of the present disclosure.

[0033] Refer to Figure 1, a TDI image sensor capable of adjusting an exposure time according to an exemplary embodiment of the present disclosure and an inspection system including the TDI image sensor may include a pixel unit 110, a light blocking unit 120, a microlens 130, a speed sensor 200, illumination light 300, a scan controller 400, and an output unit 500. At this time, the TDI image sensor may include the pixel unit 110, the light blocking unit 120, the microlens 130, the speed sensor 200, the scan controller 400, and the output unit 500. In addition, the pixel unit 110 may include the light blocking unit 120 and the microlens 130, and the scan controller 400 may include the speed sensor 200.

[0034] The pixel unit 110 is a configuration for sensing an image, and may be configured by an imaging device such as a charge coupled device. The pixel unit 110 may be configured by a plurality of row sensors, and the plurality of row sensors are configured by a plurality of imaging devices. Each of the plurality of row sensors may be arranged in a direction orthogonal to the moving direction of the scanning object 610, that is, in a direction perpendicular to the scanning direction.

[0035] The pixel unit 110 may be configured to: while moving in the column direction of each row sensor, accumulate a large amount of charges corresponding to the amount of light passing through or reflected from the scanning object 610 according to the time delay integration (TDI) method.

[0036] The light blocking unit 120 may be arranged on the front surfaces of some row sensors to prevent the light entering from the scanning object 610 from being incident on some of the row sensors configured in the pixel unit 110. For example, the light blocking unit 120 may be arranged on the front surface of each row sensor to prevent light from being incident on a part corresponding to half of the row sensor. In the present disclosure, for the convenience of description, an exemplary embodiment in which half of the row sensor is light-shielded is mainly described. However, if necessary, 1 / 3, 1 / 4, or 2 / 5 of the row sensor may be light-shielded, or the row sensors may also be light-shielded alternately one by one.

[0037] The light blocking unit 120 may be implemented by a metal light shielding layer (shown in Figures 3A to 3D ). For example, the metal light shielding layer of the light blocking unit 120 may be arranged on the front surface of the corresponding row sensor to allow light to be alternately incident on some row sensors. For example, the metal light shielding layer of the light blocking unit 120 may be arranged on the front surface of each row sensor to prevent light from being incident on half of the row sensor.

[0038] The microlens 130 may be configured such that light entering from the scanned object 610 is refracted to focus on the open portion of the pixel in the pixel unit 110. The microlens 130 may be disposed on the front surface of the light-blocking unit 120.

[0039] The speed sensor 200 may be configured to detect the moving speed of the conveying device 600 that conveys the object 610 to be scanned. For example, the speed sensor 200 may detect the moving speed of the conveying device 600 to provide the moving speed to the scanning controller 400. That is, the interval of the external line trigger signal L_pe generated whenever the conveying device 600 moves a predetermined distance (e.g., 50 μm) may be measured to detect the moving speed. The conveying device 600 used in the present disclosure may be any device suitable for moving the scanned object 610 to be scanned by the image sensor, and a typical example thereof may be a linear stage.

[0040] The illumination light 300 may be configured to emit light incident on the pixel unit 110.

[0041] The scanning controller 400 may generate an internal line trigger signal L_pi based on the externally input external line trigger signal L_pe, and control the movement of the charge in the pixel unit 110 based on the internal line trigger signal L_pi. The external line trigger signal L_pe is set to be automatically generated whenever the conveying device 600 that moves the scanned object 610 moves a predetermined distance, and is provided to the image sensor to trigger the charge to move to the next line sensor. Therefore, the movement of the scanned object 610 may be synchronized with the charge accumulation in the corresponding line sensor.

[0042] For example, whenever the external line trigger signal L_pe is input, the scanning controller 400 may generate the internal line trigger signal L_pi, and additionally generate the internal line trigger signal L_pi between the internal line trigger signals L_pi generated by the external line trigger signal L_pe. In other words, the scanning controller 400 may generate an exposure control signal E_p after a predetermined time whenever the external line trigger signal L_pe is input, and combine (e.g., by OR operation) the external line trigger signal L_pe and the exposure control signal E_p to generate the final internal line trigger signal L_pi.

[0043] More specifically, when two external row trigger signals L_pe are input, the scan controller 400 can generate three internal row trigger signals L_pi. The first internal row trigger signal L_pi and the third internal row trigger signal L_pi can be generated by the input of the external row trigger signal L_pe, while the second internal row trigger signal L_pi can be generated at a timing set by the user. In other words, when two external row trigger signals L_pe are input, an exposure control signal E_p can be additionally generated at a specific timing between them. The specific timing can be determined by a value preset by the user. In other words, when two external row trigger signals L_pe are input, the scan controller can additionally generate an exposure control signal E_p at a specific timing between the two external row trigger signals. The specific timing can be determined by a value preset by the user.

[0044] The output unit 500 can output the sensing result provided by the pixel unit 110 under the control of the scan controller 400. An inspection system for detecting defects of a scanned object can be configured by using the sensing result. According to an exemplary embodiment of the present disclosure, the output unit 500 can include appropriate buffers, amplifiers, analog-to-digital converters (ADCs), and HDR processing circuits, etc., to receive and amplify the charge accumulated and transmitted by the pixel unit 110 for each column, convert it into a digital signal, and process the digital signal. At this time, the output unit 500 can obtain a first image through a first exposure time between the first external row trigger signal L_pe and the exposure control signal E_p, and obtain a second image through a second exposure time between the exposure control signal E_p and the next external row trigger signal L_pe, so as to combine the first image and the second image to output a high dynamic range (HDR) image.

[0045] At this time, the first exposure time can be different from the second exposure time. The long exposure image generated by the longer exposure time among the first exposure time and the second exposure time can be an image for an area with a lower surface reflectivity so that it is captured darker even under the same illumination. The short exposure image generated by the shorter exposure time can be an image for an area with a high surface reflectivity so that it is captured very bright (such as metal) under the same illumination. The HDR image can be an image generated by combining the long exposure image and the short exposure image.

[0046] Figure 2 is a view showing the configuration of a pixel unit according to an exemplary embodiment of the present disclosure Figure 1 of.

[0047] Refer to Figure 2, in a TDI image sensor capable of adjusting an exposure time according to an exemplary embodiment of the present disclosure, one pixel 1 may be configured by at least two storages. In addition, one pixel may be configured by one storage. In Figure 2 , for ease of description, the first storage is denoted by 2a and the second storage is denoted by 2b. In one pixel, different images corresponding to the number of storages can be obtained. One storage may be configured by one sensing device (e.g., a charge-coupled device (CCD)). In Figure 2 , it is shown that one pixel 1 is configured by a first storage 2a and a second storage 2b.

[0048] In the pixel unit 110, N row sensors may be provided in parallel to the scanning direction, and each row sensor is configured by M imaging devices. That is, the imaging devices may be configured in an M×N matrix.

[0049] Generally, one imaging device configures one pixel 1, but the pixel unit 110 may be implemented such that multiple imaging devices configure one pixel 1.

[0050] The storages constituting one pixel 1 may be arranged along the scanning direction (i.e., the column direction of the M×N matrix), and at least two storages constitute one pixel.

[0051] The pixel unit may be configured by a time delay integration (TDI) image sensor, and one pixel may be configured by at least two storages formed in the column direction. That is, one pixel may be configured by multiple imaging devices arranged in the column direction.

[0052] The pixel unit 110 may be configured to move and accumulate sensed charges in the column direction of each row sensor according to the TDI method in order to integrate the image signal charges. The pixel unit 110 may be configured to move the charges accumulated in the storage unit in the column direction by the driving control of the scanning controller 400.

[0053] Figures 3A to 3D is a view for explaining the configuration of a pixel unit, a light-blocking unit, and a microlens in which Figure 1 are combined according to an exemplary embodiment of the present disclosure.

[0054] As Figure 2 , Figures 3A to 3D shown, the light-blocking unit 120 may be configured by a metal mask. The light-blocking unit 120 may be configured to receive a part (e.g., half, 3 / 5, or 2 / 3) of the light incident on each row L1, L2, L3, and L4 of the pixel unit 110 and block the light from the remaining part (e.g., half, 2 / 5, or 1 / 3).

[0055] A microlens 130 may be provided at the upper end of the exposed area of the light-blocking unit 120. The microlens 130 is configured to enhance the light incident on the line sensor portion exposed by the light-blocking unit 120. The microlens 130 may be provided in each exposed area of the light-blocking unit 120 to allow more incident light to be incident on the pixel unit 110. As Figure 3D shown, voltages V1, V2, and V3 of the CCD are sequentially applied so that the charges accumulated in the CCD move to adjacent CCDs (or the charges accumulated in a part of the CCD move to the rest of the CCD), and the charges sensed by repeating this operation are output from the charge storage node FD.

[0056] Figure 4 is a view showing Figure 1 the schematic configuration of the scan controller according to an exemplary embodiment of the present disclosure.

[0057] As Figure 4 shown, the scan controller 400 may include a register 410, an exposure control signal generator 420, and a row voltage generator 430.

[0058] The register 410 may store digital values according to the exposure time ratio set by the user and provide the stored values to the exposure control signal generator 420. The register 410 may be used to calculate the exposure time of the line sensor according to the exposure time ratio set by the user.

[0059] The exposure control signal generator 420 may generate an exposure control signal E_p based on the output value of the register 410 and an external row trigger signal L_pe input from the outside. For example, when the external row trigger signal L_pe is input and the exposure time set by the user has elapsed, the exposure control signal generator 420 may generate and output the exposure control signal E_p. At this time, the output signal stored in the register 410 indicates the exposure time ratio of two images and is converted into timing to generate the exposure control signal E_p based on this value. As a result, the exposure control signal generator 420 may adjust a predetermined time according to the output signal of the register 410, and when the adjusted predetermined time has elapsed after the external row trigger signal L_pe is input, generate and output the exposure control signal E_p.

[0060] An internal row trigger signal L_pi may be generated based on the input external row trigger signal L_pe and the generated exposure control signal E_p.

[0061] At this time, the internal row trigger signal L_pi may be generated in digital logic (e.g., in an OR gate).

[0062] The row voltage generator 430 can generate a plurality of row voltages V1, V2, and V3 input to each row sensor based on an internal row trigger signal L_pi.

[0063] Figure 5 is a view showing a schematic configuration of Figure 4 an exposure control signal generator according to an exemplary embodiment of the present disclosure.

[0064] As Figure 5 shown, the exposure control signal generator 420 can include a counter control logic 421, a counter 422, a conversion logic 423, a comparator 424, and a pulse generator 425.

[0065] The counter control logic 421 can receive an external row trigger signal L_pe and an exposure control signal E_p, and output a counter activation signal en. For example, when the external row trigger signal L_pe is input, the counter control logic 421 can output the counter activation signal en until the exposure control signal E_p is input. That is, when the external row trigger signal L_pe is input, the counter control logic 421 can enable the counter activation signal en, and when the exposure control signal E_p is input, the counter control logic 421 can disable the counter activation signal en. At this time, when the counter activation signal en is enabled, the counter activation signal en can be at a high digital logic level, and when the counter activation signal en is disabled, the counter activation signal en can be at a low digital logic level. The counter control logic 421 can be implemented by an S-R latch circuit.

[0066] The counter 422 can receive the counter activation signal en and output a count value. For example, the counter 422 can count only during the period when the counter activation signal en is enabled to a high level to increment the value by one and output the count value.

[0067] When the external row trigger signal L_pe is input, the count value of the counter 422 is reset, and the counter 422 can count during the period when the counter activation signal en is enabled to a high level to increment the value by one.

[0068] The conversion logic 423 can include a calculation function for converting into a plurality of clock pulses based on the exposure ratio stored in Figure 4 the register 410 of the scan controller to cause the counter 422 to increment. For example, the timing of generating the exposure control signal E_p after the external row trigger signal L_pe is input can be determined corresponding to the number of clock pulses.

[0069] The comparator 424 may output a result of comparing the value of the counter 422 , which is counted up during a period in which the counter activation signal en is enabled to a high level, with the number of clock pulses calculated based on the exposure ratio.

[0070] For example, when the value of the counter 422 is equal to the output value of the conversion logic 423 , the comparator 424 may output a comparison result signal R_c having a high level.

[0071] For example, when the number of clock pulses calculated based on the exposure ratio is 256 and the value of the counter counted up during the counter activation period is 256, the comparator 424 may output the comparison result signal R_c having a high level.

[0072] The pulse generator 425 receives the comparison result signal R_c and outputs the exposure control signal E_p. For example, when the comparison result signal R_c is at a high level, the pulse generator 425 may output the exposure control signal E_p.

[0073] Figure 6 It is used to illustrate Figure 5 A view of the operation of the exposure control signal generator.

[0074] refer to Figure 6 , which will be described below Figure 5 The operation of the exposure control signal generator 420 is shown.

[0075] The count value is an output signal of the counter 422 in the exposure control signal generator 420, and may be a count value counted up during a period in which the counter activation signal en generated by the external row trigger signal L_pe and the exposure control signal E_p in the counter control logic 421 is enabled. That is, the counter 422 may count up during a period in which the counter activation signal en is enabled, then stop counting during a period in which the counter activation signal en is disabled, and then wait until the next external row trigger signal L_pe is input.

[0076] Here, when the count value is n, an exposure control signal E_p is generated. n can be a number calculated by the conversion logic 423 based on the exposure ratio stored in the register 410 of the scan controller. For example, when the period of the external row trigger signal L-pe is 100 relative to the counter clock, if the exposure ratio is set to 25, the value of n can be 25. More specifically, when the external row input trigger signal L-pe is input, the counter is reset to 0, and the counter activation signal is enabled to start incrementing the count. When the count value reaches 25, if the exposure control signal E_p is output, the counter activation signal is disabled, and the counter 422 stops operating until the next external row trigger signal L-pe is input. As a result, immediately after the external row trigger signal L-pe is input, the charge accumulated in each pixel of the TDI sensor moves row by row, and when the count value reaches 25, it moves again, and immediately after the next external row trigger signal L-pe is input, it moves again. Here, when the period of the external row trigger signal L-pe corresponds to approximately 100 counter clock pulses, a short exposure image with 25% (1 / 4) exposure and a long exposure image with 75% (3 / 4) exposure can be obtained.

[0077] In the above exemplary embodiment, an example has been described in which the interval between external row trigger signals is divided into 5 equal parts and set with an exposure time ratio of 2:3 or 1:4. However, this is only an example, and it can be easily understood by those skilled in the art that the interval of the external row trigger signal L-pe can be divided into any integer number of equal parts.

[0078] In addition, the interval between external row trigger signals is ideally constant, but in practice, there may be slight jitter. Therefore, the previous external row trigger signal interval can be measured and divided into integer equal parts to convert the interval into an integer value corresponding to the timing of generating the exposure control signal. In addition, according to another exemplary embodiment, the previous external row trigger signal interval can be measured and divided by 1, 5, or 10 and used for the output of the oscillator signal OSC. According to another exemplary embodiment, the external row trigger signal interval can be measured several times (e.g., three or five times), and the average value can be calculated and used for division or oscillator signal (OSC) output. Alternatively, a signal interval value can be received from the user and used for division by an integer and oscillator signal (OSC) output.

[0079] Figure 7 is a view showing a schematic configuration of a scan controller according to another exemplary embodiment of the present disclosure.

[0080] As Figure 7As shown, the scan controller 400 may include a register 410', an exposure control signal generator 420', a signal generator 430', and a row voltage generator 440.

[0081] The register 410’ may store digital signals R_outA, R_outB, and R_outC according to an exposure time ratio set by a user, and provide the stored values to the exposure control signal generator 420’. The register 410’ may be used to determine an exposure time of a row sensor according to the exposure time ratio set by the user.

[0082] The exposure control signal generator 420’ may generate an exposure control signal E_p based on output signals R_outA, R_outB, and R_outC of the register 410’ and an external row trigger signal L_pe input from the outside. For example, when the external row trigger signal L_pe is input and a user-set exposure time has elapsed, the exposure control signal generator 420’ may generate and output the exposure control signal E_p. At this time, the output signals R_outA, R_outB, and R_outC of the register 410’ may adjust a predetermined time of the exposure control signal generator 420’. As a result, the exposure control signal generator 420’ may adjust the predetermined time according to the output signals R_outA, R_outB, and R_outC of the register 410’, and generate and output the exposure control signal E_p signal when the adjusted predetermined time has elapsed after the external row trigger signal L_pe is input.

[0083] The signal generator 430’ may generate an internal row trigger signal L_pi based on the external row trigger signal L_pe and the exposure control signal E_p. For example, whenever the external row trigger signal L_pe and the exposure control signal E_p are input, the signal generator 430’ may generate the internal row trigger signal L_pi.

[0084] At this time, the signal generator 430’ may be implemented by digital logic such as an OR gate.

[0085] The row voltage generator 440 may generate a plurality of row voltages V1, V2, and V3 input to each row sensor based on the internal row trigger signal L_pi.

[0086] Figure 8 FIG. is a schematic configuration diagram showing an exposure control signal generator according to another exemplary embodiment of the present disclosure.

[0087] As Figure 8 shown, the exposure control signal generator 420' may include a latch circuit 421', an oscillator 422', a counter 423', a comparison circuit 424', and a pulse output circuit 425'.

[0088] The latch circuit 421' can receive an external row trigger signal L_pe and an exposure control signal E_p, and output an oscillator activation signal O_en. For example, when the external row trigger signal L_pe is input, the latch circuit 421' can enable the oscillator activation signal O_en until the exposure control signal E_p is input. That is to say, when the external row trigger signal L_pe is input, the latch circuit 421' can enable the oscillator activation signal O_en, and when the exposure control signal E_p is input, the latch circuit 421' can disable the oscillator activation signal O_en. At this time, when the oscillator activation signal O_en is enabled, the oscillator activation signal O_en can be a high digital logic level, and when the oscillator activation signal O_en is disabled, the oscillator activation signal O_en can be a low digital logic level. The latch circuit 421' can be implemented by an S-R latch circuit.

[0089] The oscillator 422' can receive the oscillator activation signal O_en and a speed sensing signal V_d, and output an oscillator signal OSC. For example, the oscillator 422' can output an oscillator signal OSC that periodically shifts only during the period when the oscillator activation signal O_en is enabled to a high level. For example, the oscillator signal OSC is a signal that periodically shifts between a high level and a low level. At this time, the oscillator 422' that generates the periodically shifted oscillator signal OSC can change the period of the oscillator signal OSC based on the speed sensing signal V_d. The speed sensing signal V_d can be Figure 1 the output signal of the speed sensor 200 or a signal corresponding to the input speed of the external row trigger signal L_pe. In addition, the speed sensing signal V_d can be a value set by the user.

[0090] The oscillator 422' can generate the oscillator signal OSC with a period corresponding to a value obtained by dividing the input period of the external row trigger signal L_pe by an integer.

[0091] The counter 423' can receive the oscillator signal OSC and output a counter signal CNT<0:2>. For example, whenever the oscillator signal OSC shifts to a high level, the counter 423' can increment the count value of the counter signal CNT<0:2>. More specifically, when the oscillator signal OSC shifts to the first high level, the counter 423' can output a counter signal CNT<0:2> with a count value of (1, 0, 0). When the oscillator signal OSC shifts to the second high level, the counter 423' can output a counter signal CNT<0:2> with a count value of (1, 1, 0). When the oscillator signal OSC shifts to the third high level, the counter 423' can output a counter signal CNT<0:2> with a count value of (1, 1, 1). At this time, the high level is represented by 1, and the low level is represented by 0.

[0092] The comparison circuit 424' receives the first to third delay control signals R_outA, R_outB, and R_outC and the counter signal CNT<0:2>, and outputs a comparison result signal R_c.

[0093] For example, when the first to third delay control signals R_outA, R_outB, and R_outC and the counter signal CNT<0:2> are at the same digital logic level, the comparison circuit 424' can output a comparison result signal R_c with a high level. More specifically, when the levels of the first to third delay control signals R_outA, R_outB, and R_outC are equal to the level of the counter signal CNT<0:2>, the comparison circuit 424' can output a comparison result signal R_c with a high level.

[0094] When all of the first to third delay control signals R_outA, R_outB, and R_outC are at a high level, if the counter signal CNT<0:2> is (1, 1, 1), the comparison circuit 424' can output a comparison result signal R_c with a high level.

[0095] The pulse output circuit 425' can receive the comparison result signal R_c and output an exposure control signal E_p. For example, when the comparison result signal R_c is at a high level, the pulse output circuit 425' can output the exposure control signal E_p.

[0096] Reference Figure 9 , the operation of the exposure control signal generator 420' shown below will be described. Figure 8 in.

[0097] In Figure 9 A, it is assumed that the first delay control signal R_outA is at a low level, the second delay control signal R_outB is at a high level, and the third delay control signal R_outC is at a low level. In addition, in Figure 9 , it is assumed that an oscillator signal having a period corresponding to 1 / 5 of the input period of the external row trigger signal L_pe is generated. The oscillator 422' can generate an oscillator signal OSC that is five times faster than the input period of the external row trigger signal L_pe based on the speed sensing signal V_d. At this time, the oscillator 422' can change the period of the oscillator signal OSC based on the speed sensing signal V_d.

[0098] When the external row trigger signal L_pe is input, the latch circuit 421' enables the oscillator activation signal O_en to a high level.

[0099] At this time, the first external row trigger signal L_pe is input, and the first internal row trigger signal L_pi is generated.

[0100] When the oscillator activation signal O_en is enabled to a high level, the oscillator 422’ generates an oscillator signal OSC that periodically shifts between a high level and a low level.

[0101] When the oscillator signal OSC shifts to the first high level, the counter 423’ can output a counter signal CNT<0:2> with a count value of (0, 0, 1).

[0102] When the oscillator signal OSC shifts to the second high level, the counter 423’ can output a counter signal CNT<0:2> with a count value of (0, 1, 0).

[0103] At this time, since the first delay control signal to the third delay control signal R_outA, R_outB, and R_outC are (0, 1, 0), when the count value of the counter signal CNT<0:2> is (0, 1, 0), the comparison circuit 424’ outputs a comparison result signal R_c with a high level.

[0104] The pulse output circuit 425’ receives the high-level comparison result signal R_c to generate an exposure control signal E_p.

[0105] At this time, when the exposure control signal E_p is generated, the second internal row trigger signal L_pi is generated.

[0106] When the exposure control signal E_p is output, the latch circuit 421’ prohibits the oscillator activation signal O_en to a low level, and the counter 423’ initializes the counter signal CNT<0:2>. At this time, the count value of the initialized counter signal CNT<0:2> can be (0, 0, 0). In addition, the initialized counter signal CNT<0:2> maintains the initialization value until the second external row trigger signal L_pe is input.

[0107] When the second external row trigger signal L_pe is input, the oscillator activation signal O_en is enabled to a high level, and the third internal row trigger signal L_pi is generated.

[0108] As a result, the interval between the first external row trigger signal L_pe and the second external row trigger signal L_pe can be equally divided into five sections by the oscillator signal OSC, and the second internal row trigger signal L_pi can be generated in the second section (0, 1, 0) corresponding to the values (0, 1, 0) of the first delay control signal to the third delay control signal R_outA, R_outB, and R_outC set by the user.

[0109] Since the internal row trigger signal L_pi generated as shown in Figure 9 A determines the exposure time of light for each row of the pixel unit 110, the charge accumulated during the period between the first internal row trigger signal L_pi and the second internal row trigger signal L_pi (i.e., the exposure time A) can be shifted, and the charge accumulated during the exposure time B between the second internal row trigger signal L_pi and the third internal row trigger signal L_pi can be shifted.

[0110] In Figure 9 B, it is assumed that the first delay control signal R_outA is at a low level, the second delay control signal R_outB is at a low level, and the third delay control signal R_outC is at a high level.

[0111] When the external row trigger signal L_pe is input, the latch circuit 421' enables the oscillator activation signal O_en to a high level.

[0112] At this time, when the first external row trigger signal L_pe is input, the first internal row trigger signal L_pi is generated.

[0113] When the oscillator activation signal O_en is enabled to a high level, the oscillator 422' generates an oscillator signal OSC that is periodically shifted between a high level and a low level.

[0114] When the oscillator signal OSC shifts to the first high level, the counter 423' can output a counter signal CNT<0:2> with a count value of (0, 0, 1).

[0115] At this time, since the first delay control signal to the third delay control signal R_outA, R_outB, and R_outC are (0, 0, 1), when the count value of the counter signal CNT<0:2> is (0, 0, 1), the comparison circuit 424' outputs a comparison result signal R_c with a high level.

[0116] The pulse output circuit 425' receives the comparison result signal R_c with a high level to generate an exposure control signal E_p.

[0117] At this time, when the exposure control signal E_p is generated, the second internal row trigger signal L_pi is generated.

[0118] When the exposure control signal E_p is output, the latch circuit 421' disables the oscillator activation signal O_en to a low level, and the counter 423' initializes the counter signal CNT<0:2>. At this time, the count value of the initialized counter signal CNT<0:2> can be (0, 0, 0). In addition, the initialized counter signal CNT<0:2> maintains the initialized value until the second external row trigger signal L_pe is input.

[0119] When the second external row trigger signal L_pe is input, the oscillator activation signal O_en is enabled to a high level, and the third external row trigger signal L_pi is generated.

[0120] As a result, the interval between the first external row trigger signal L_pe and the second external row trigger signal L_pe is equally divided into five sections by the oscillator signal OSC, and the second internal row trigger signal L_pi can be generated in the first section (0, 0, 1) corresponding to the values (0, 0, 1) of the first to third delay control signals R_outA, R_outB, and R_outC set by the user.

[0121] Since the internal row trigger signal L_pi generated as shown in Figure 9 B determines the exposure time for the light of each row of the pixel unit 110, the charge accumulated during the time period between the first internal row trigger signal L_pi and the second internal row trigger signal L_pi (i.e., exposure time A) can be moved, and the charge accumulated during the exposure time B between the second internal row trigger signal L_pi and the third internal row trigger signal L_pi can be moved.

[0122] As described in reference Figure 9 A and Figure 9 B, the TDI image sensor and the inspection system including the TDI image sensor can equally divide the interval between the first external row trigger signal and the second external row trigger signal by an integer into sections of a predetermined size (e.g., 5 equal parts, 4 equal parts, 8 equal parts, or 16 equal parts), and generate an exposure control signal in any one of the sections divided by the user, so as to generate an internal row trigger signal whenever an external row trigger signal and an exposure control signal are input or generated.

[0123] In the above exemplary embodiment, an example of dividing the interval between the external row trigger signals into 5 equal parts and setting the exposure time ratio to 1:4 has been described. However, this is only an example, and those skilled in the art can easily understand that the period of the external row trigger signal L_pe can be divided into any integer number of parts (e.g., 4 equal parts, 8 equal parts, 16 equal parts, or 32 equal parts).

[0124] In addition, although the interval between the external row trigger signals is ideally constant, in practice, there may also be slight jitter. Therefore, the previous external row trigger signal interval can be measured and divided by an integer and evenly divided to change the period of the oscillator signal OSC.

[0125] In addition, according to another exemplary embodiment, a previous external row trigger signal interval can be measured and divided by 1, 5, or 10, and this is used for the output of the oscillator signal OSC. According to another exemplary embodiment, the external row trigger signal interval is measured several times (e.g., three or five times), and an average value can be calculated to use this average value for division or the oscillator signal (OSC) output. Alternatively, the external row trigger signal interval is measured several times (e.g., once, three, or five times) by clock counting, and a previous value or an average value (e.g., 100 clocks) can be divided by an integer (e.g., 20 clocks:80 clocks) according to a signal interval value (e.g., 1:4) received from the user for determining a short exposure time and a long exposure time.

[0126] Figure 10 is a view for explaining the operation of a TDI image sensor capable of adjusting an exposure time according to an exemplary embodiment of the present disclosure.

[0127] Figure 10 is a view for explaining the charge movement of a row sensor by an internal row trigger signal.

[0128] As Figure 10 shown, whenever the internal row trigger signal L_pi is generated, repeatedly, charge moves from a portion of the row sensor where light is blocked by a metal light shielding layer (e.g., the lower half, 2 / 5, or 1 / 3) to a portion of the row sensor where light is incident on an open surface (e.g., the upper half, 3 / 5, and 2 / 3), and charge moves from a portion of the row sensor where light is incident on an open surface to a portion of the row sensor where light is blocked by a metal light shielding layer.

[0129] Accordingly, the time during which a portion of the row sensor exposed to light is exposed can be equal to the interval of the internal row trigger signal L-Pi.

[0130] Accordingly, two types of cumulative charges having different exposure times can be transferred in the column direction of each row sensor.

[0131] As a result, a TDI image sensor according to an exemplary embodiment of the present disclosure and an inspection system including the same sense two types of cumulative charges having different exposure times (e.g., cumulative charges representing long exposure and short exposure) and combine the sensing results to generate a high dynamic range (HDR) image. At this time, the ratio of exposure time A to exposure time B can be set by the user and stored in the register 410', so that the HDR ratio can be easily changed.

[0132] Figure 11 is a view for explaining a control method of a TDI image sensor according to an exemplary embodiment of the present disclosure.

[0133] Refer toFigure 11 , the control method of the TDI image sensor of the present disclosure may include an arrangement step, a setting step, and a control step.

[0134] As Figure 3A and Figure 3B shown, the arrangement step may include the step of arranging a light-blocking unit (metal mask) in a part of the front surface of each row sensor. At this time, the arrangement step may further include the step of arranging a microlens in the remaining part of the row sensor where the light-blocking unit is not arranged.

[0135] The setting step is the step of storing information (e.g., exposure time A and exposure time B or the ratio of exposure times) corresponding to the two exposure times of the remaining part of the row sensor (where the incidence of light is not blocked by the light-blocking unit). The setting step may be the step of storing the value set by the user in the Figure 4 register shown in

[0136] In addition, in the setting step, the interval of the external row trigger signal (i.e., the input timing) is measured a predetermined number of times to calculate an average value for determining the period of the oscillator 422' or determining the exposure time. Therefore, the influence of the jitter that may occur in the external row trigger signal can be minimized.

[0137] The control step is the step of alternately applying two exposure times to each row sensor, and includes the step of generating an internal row trigger signal based on the external row trigger signal as Figure 10 shown in

[0138] For example, the control step may include: a first generation control step that generates a first internal row trigger signal when a first external row trigger signal is input; a second generation control step that generates a second internal row trigger signal when a time corresponding to the value stored in the register has elapsed after the input of the first external row trigger signal; and a third generation control step that generates a third internal row trigger signal when a second external row trigger signal is input.

[0139] In addition, the control step includes: a first exposure step that exposes the remaining part of the row sensor during the interval between the first internal row trigger signal and the second internal row trigger signal, and moves the accumulated charge to the part of the row sensor where the light-blocking unit is arranged; and a second exposure step that exposes the remaining part of the sensor during the interval between the second internal row trigger signal and the third internal row trigger signal, and moves the accumulated charge to the part of the sensor where the light-blocking unit is arranged. The first exposure step and the second exposure step may be repeatedly executed.

[0140] The first exposure step and the second exposure step are steps of accumulating charges by light with different exposure times. In the first exposure step and the second exposure step, the exposure step with a shorter exposure time can be a step for generating a short-exposure image, and the exposure step with a longer exposure time can be a step for generating a long-exposure image.

[0141] Figure 8 The oscillator 422' shown in can: generate an oscillator signal OSC having a period corresponding to a value obtained by dividing the input period of the external row trigger signal L_pe by an integer; equally divide the interval between two external row trigger signals L_pe; and select one or more of the divided sections as the value stored in the register 410'. An internal row trigger signal that separates the exposure time A and the exposure time B can be generated by the selected section.

[0142] Therefore, charges can be accumulated with different exposure times, and the long-exposure image and the short-exposure image can be divided according to the amount of accumulated charges.

[0143] For example, as Figure 9 shown in B, when an oscillator signal OSC that is shifted by five cycles between the first external row trigger signal L_pe and the second external row trigger signal L_pe is generated and an internal row trigger signal L_pi is generated at the timing at the end of the first cycle of the oscillation signal OSC, the short-exposure image can be an image represented by the amount of charges that are exposed for 1 / 5 relatively, and the long-exposure image can be an image represented by the amount of charges that are exposed for 4 / 5 relatively. At this time, the internal row trigger signal L_pi generated between the first external row trigger signal L_pe and the second external row trigger signal L_pe can be the value stored in the register, that is, the value set by the user.

[0144] Therefore, the TDI image sensor and the inspection system according to the exemplary embodiment of the present disclosure can generate short-exposure images and long-exposure images at a ratio set by the user.

[0145] The TDI image sensor and the inspection system including the TDI image sensor according to the exemplary embodiment of the present disclosure can generate short-exposure (or low-luminance) images and long-exposure (or high-luminance) images according to different exposure times set by the user, and use the short-exposure images and the long-exposure images to generate HDR images.

[0146] In the present invention, those skilled in the art can make various substitutions, modifications, and changes without departing from the technical spirit of the present invention, and thus, the present invention is not limited to the above embodiments and drawings.

Claims

1. A TDI image sensor capable of adjusting the exposure time, comprising: A pixel unit, which includes a plurality of row sensors. In the plurality of row sensors, the incidence of light is blocked by a light-blocking unit in a part of each row sensor, and the remaining part of each row sensor is exposed. A scan controller, which controls the exposure of the exposed part of the row sensor with different exposure times to generate a sensing result for a first exposure time and a sensing result for a second exposure time. And An output unit, which generates an image based on the sensing result for the first exposure time and the sensing result for the second exposure time. Wherein, the scan controller generates an internal row trigger signal based on an external row trigger signal, and the internal row trigger signal controls the exposure of the exposed part of the row sensor. Wherein, the external row trigger signal is automatically generated whenever the scanned object moves a predetermined distance. Wherein, whenever the external row trigger signal is input, the scan controller generates an exposure control signal after a predetermined time, and combines the external row trigger signal and the exposure control signal to generate the internal row trigger signal. Wherein, the scan controller generates the exposure control signal at a predetermined specific timing between two external row trigger signals. Wherein, the scan controller includes: A register, which stores a predetermined value and outputs an exposure ratio corresponding to the stored value. An exposure control signal generator, which generates an exposure control signal based on the external row trigger signal and the exposure ratio. A signal generator, which generates the internal row trigger signal based on the external row trigger signal and the exposure control signal.

2. The TDI image sensor according to claim 1, wherein, The exposure control signal generator includes: A counter control logic, which receives the external row trigger signal and the exposure control signal and outputs a counter activation signal. A counter, which receives the counter activation signal and outputs a count value. A conversion logic, which converts to the number of clock pulses based on the exposure ratio stored in the register to determine the timing of generating the exposure control signal. A comparator, which outputs a result of comparing the count value that will be incremented during the period when the counter activation signal is enabled with the number of clock pulses calculated based on the exposure ratio. A pulse generator, which receives the comparison result signal of the comparator and outputs the exposure control signal.

3. The TDI image sensor according to claim 1, wherein, Whenever the external row trigger signal is input, the scan controller generates the internal row trigger signal, and additionally generates the internal row trigger signal before the next external row trigger signal is generated after the external row trigger signal is input.

4. The TDI image sensor according to claim 3, wherein, The scan controller allows the timing of the additionally generated internal row trigger signal to correspond to the timing set by the user.

5. The TDI image sensor according to claim 4, wherein, The scan controller includes: A register, which stores a predetermined timing and outputs a delay control signal corresponding to the stored timing. An exposure control signal generator, which generates an exposure control signal based on the external row trigger signal and the delay control signal. A signal generator that generates the internal row trigger signal based on the external row trigger signal and the exposure control signal.

6. The TDI image sensor according to claim 5, wherein, The exposure control signal generator includes: A latch circuit that enables the oscillator activation signal after the external row trigger signal is input until the exposure control signal is input; An oscillator that generates an oscillator signal during the enabling period of the oscillator activation signal; A counter that increments the count value of the counter signal whenever the oscillator signal is shifted to a specific level; A comparison circuit that compares the count value of the counter signal with the delay control signal to generate a comparison result signal; and A pulse output circuit that generates the exposure control signal based on the comparison result signal.

7. A TDI image sensor capable of adjusting the exposure time, comprising: A pixel unit including a plurality of row sensors; A light-blocking unit that blocks light from being incident on a part of each of the plurality of row sensors; A scan controller that generates an exposure control signal based on an external row trigger signal, generates an internal row trigger signal based on the external row trigger signal and the exposure control signal, and controls the movement of charges of the plurality of row sensors based on the internal row trigger signal, wherein the external row trigger signal is automatically generated whenever the scanning object moves a predetermined distance, and wherein each of the plurality of row sensors includes a blocked portion blocked by the light-blocking unit and an unblocked exposed portion.

8. A TDI image sensor capable of adjusting the exposure time, comprising: A pixel unit including a plurality of row sensors; A light-blocking unit that blocks light from being incident on some of the plurality of row sensors; A scan controller that generates an exposure control signal based on an external row trigger signal, generates an internal row trigger signal based on the external row trigger signal and the exposure control signal, and controls the movement of charges of the plurality of row sensors based on the internal row trigger signal, wherein the external row trigger signal is automatically generated whenever the scanning object moves a predetermined distance, and wherein the scan controller equally divides the interval between the first external row trigger signal and the second external row trigger signal into predetermined sections, generates the exposure control signal based on a predetermined exposure ratio during the divided periods, and outputs the generated exposure control signal as the internal row trigger signal.

9. The TDI image sensor according to claim 8, wherein, Whenever the external row trigger signal is input, the scan controller generates an exposure control signal after a predetermined time, and combines the external row trigger signal and the exposure control signal to output the internal row trigger signal.

10. The TDI image sensor according to claim 8, wherein, The scan controller generates the exposure control signal at a predetermined specific timing between two external row trigger signals.

11. The TDI image sensor according to claim 10, wherein, The scan controller includes: A counter control logic that receives the external row trigger signal and the exposure control signal and outputs a counter activation signal; A counter that receives the counter activation signal and outputs a count value; A conversion logic that converts, based on an exposure ratio stored in a register, into the number of clock pulses for incrementing the counter; A comparator that outputs a result of comparing a counter value that is incremented during a period when the counter activation signal is enabled with the number of clock pulses calculated based on the exposure ratio; and A pulse generator that receives the comparison result signal of the comparator and outputs the exposure control signal.

12. A control method for a TDI image sensor that can adjust an exposure time and includes a plurality of row sensors, the control method comprising: An arrangement step of arranging an optical blocking unit in a part of the front surface of each row sensor; A setting step of storing information in a register, where the information corresponds to two exposure times of the remaining part of the row sensor in which light is incident without being blocked by the optical blocking unit; and A control step of generating an exposure control signal based on an external row trigger signal, and generating an internal row trigger signal based on the external row trigger signal and the exposure control signal to alternately apply two exposure times to each row sensor, wherein the external row trigger signal is automatically generated whenever the scanning object moves a predetermined distance, and wherein an interval between a first external row trigger signal and a second external row trigger signal is equally divided into predetermined sections, and the exposure control signal is generated based on a predetermined exposure ratio during the divided periods and the generated exposure control signal is output as the internal row trigger signal.

13. The control method according to claim 12, wherein, The control step includes: A first generation control step of generating a first internal row trigger signal when the first external row trigger signal is input; A second generation control step of generating a second internal row trigger signal when a time corresponding to a value stored in the register has elapsed after the input of the first external row trigger signal; and A third generation control step of generating a third internal row trigger signal when the second external row trigger signal is input.

14. The control method according to claim 13, wherein, The control step includes: A first exposure step of exposing the remaining part of the row sensor during an interval between the first internal row trigger signal and the second internal row trigger signal, and moving the accumulated charge to the part of the row sensor where the optical blocking unit is arranged; and A second exposure step of exposing the remaining part of the row sensor during an interval between the second internal row trigger signal and the third internal row trigger signal, and moving the accumulated charge to the part of the row sensor where the optical blocking unit is arranged; wherein the first exposure step and the second exposure step are alternately executed.

Images