Test method, test apparatus, and program

Abstract

SOLUTION: This test method includes: a measurement step in which, regarding each of some of a plurality of terminals for outputting a single-end signal and provided in the device under test, a difference value with the output value of a reference terminal which is different from the terminal is measured; and an assessment step S29 in which assessment is made as to whether or not the device under test is good, on the basis of whether or not the difference value of each of some terminals is within a first reference range. In the measurement step, the output value of each of at least one terminal among the plurality of terminals is further measured, and in the assessment step S29, assessment is further made as to whether or not the device under test is good on the basis of whether or not the output value of each of the at least one terminal is within a second reference range, and on the basis of whether or not the difference value among the output value of each of the at least one terminal is within a third reference range.EFFECT: This makes it possible to heighten the accuracy of test and shorten the test time.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a test method, a test apparatus, and a program.

Background Art

[0002] Patent Document 1 describes that "the voltage of each output pin is obtained by sequentially accumulating the measured voltage differences from the nth voltage measurement unit V un in order" (paragraph 0007). [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 8-62307

Summary of the Invention

[0003] In a first aspect of the present invention, a test method is provided. The test method may include a measurement step of measuring, for each of some of a plurality of terminals provided in a device under test and outputting single-ended signals, a difference value between an output value of the terminal and an output value of a reference terminal different from the terminal among the plurality of terminals. The test method may include a determination step of determining whether the device under test is good or bad based on whether the difference value of each of the some terminals is within a first reference range.

[0004] In the measurement step, the output value of at least one of the plurality of terminals may be further measured. In the determination step, whether the device under test is good or bad may be further determined based on whether the output value of at least one of the terminals is within a second reference range and whether the difference value between the output values of at least one of the terminals is within a third reference range.

[0005] The plurality of terminals may form at least one chain relationship in which each terminal is sequentially used as a reference terminal. In the measurement step, for each pair of adjacent terminals in the chain relationship, the other terminal may be used as a reference terminal for one terminal.

[0006] The measurement stage may further measure the output value of one end terminal in each chain relationship.

[0007] In the measurement stage, the difference value between the output value of each terminal in at least one terminal group having two or more terminals among some terminals and the output value of a common reference terminal associated with the terminal group among a plurality of terminals may be measured.

[0008] At least one chain relationship in which reference terminals are sequentially used between two or more terminal groups may be formed by a plurality of terminal groups obtained by grouping a plurality of terminals. In the measurement stage, between two adjacent terminal groups in the chain relationship, for one terminal group, any terminal in the other terminal group may be used as a reference terminal.

[0009] In the measurement stage, the output value of each terminal in the terminal group at one end in each chain relationship may be further measured.

[0010] The device under test may be capable of outputting a plurality of gradations from each terminal. In the measurement stage, measurement may be performed by causing each terminal to output each gradation. In the determination stage, determination may be made based on the measurement results at each gradation.

[0011] The device under test may be a display driver having a plurality of terminals for controlling a plurality of pixels of a display. The output value may be a value indicated by the magnitude of a voltage.

[0012] In the measurement stage, the difference value may be measured between terminals corresponding to pixels adjacent to each other in the display among a plurality of terminals.

[0013] In a second aspect of the present invention, a test apparatus is provided. The test apparatus may include a measurement unit that measures a difference value between an output value of a reference terminal different from a terminal among a plurality of terminals provided in the device under test and outputting single-ended signals, for each of some of the plurality of terminals. The test apparatus may include a determination unit that determines whether the device under test is good or bad based on whether the difference value of each of some of the terminals is within a first reference range.

[0014] In a third aspect of the present invention, a program is provided. The program may cause a computer to function as a measurement unit that measures a difference value between an output value of a reference terminal different from a terminal among a plurality of terminals provided in the device under test and outputting single-ended signals, for each of some of the plurality of terminals. The program may cause a computer to function as a determination unit that determines whether the device under test is good or bad based on whether the difference value of each of some of the terminals is within a first reference range.

[0015] Note that the above summary of the invention does not list all the necessary features of the present invention. Also, sub-combinations of these feature groups may also be inventions.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Best Mode for Carrying Out the Invention

[0017] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0018] [1. Test System 1] FIG. 1 shows a test system 1 according to the present embodiment. The test system 1 includes a device under test 100 and a test apparatus 200.

[0019] [1-1. Device Under Test 100] The device under test 100 has a plurality of terminals 10, and the output from the terminals 10 is tested by the test apparatus 200. The device under test 100 may be capable of outputting a plurality of gradations (for example, 256 gradations, 1024 gradations, 4096 gradations, etc.) from each terminal 10. The device under test 100 may be a display driver having a plurality of terminals 10 for controlling a plurality of pixels of a display (not shown). Each terminal may output a single-ended signal. A single-ended signal may be a signal that represents a signal value depending on whether it is high or low with respect to a certain reference (for example, zero). Each terminal 10 is associated with one of the display colors constituting the pixels of the display, and the arrangement of the terminals 10 in the device under test 100 may correspond to the arrangement of the corresponding pixels in the display.

[0020] The plurality of terminals 10 may be grouped into a plurality of terminal groups 11 by the test apparatus 200. For example, the plurality of terminals 10 may be grouped according to the position of the terminals 10 in the device under test 100. Also, the terminals 10 included in each terminal group 11 may be arranged close to each other in the device under test 100. Note that each terminal group 11 may include at least one terminal 10. Also, each terminal group 11 may include the same number of terminals 10, or may include different numbers of terminals 10.

[0021] [1-2. Test device 200] The test device 200 tests the quality of the device under test 100. The test device 200 includes a test controller 201, a measurement unit 202, and a determination unit 203.

[0022] [1-2-1. Test controller 201] The test controller 201 controls each part of the test device 200 and causes the device under test 100 to perform operations according to the test conditions. For example, the test controller 201 may supply a test pattern signal to the device under test 100 to cause an output value corresponding to a specified gradation to be output from at least some of the terminals 10 at a desired timing. The output value output from the terminal 10 may be supplied to a transmission path Ch for transmitting the output value. Note that the test controller 201 may be realized by software being executed by a processor or the like.

[0023] [1-2-2. Measurement unit 202] The measurement unit 202 may be connected to the terminal 10 via the transmission path Ch. The measurement unit 202 measures the difference value between the output value of each of the terminals 10 (also referred to as non-representative terminals 10H) in at least one terminal group 11 (also referred to as a non-representative terminal group 11H) having two or more terminals 10 out of the plurality of terminal groups 11 and the output value of the reference terminal 10K for each of the non-representative terminal groups 11H among the plurality of terminals 10. The reference terminal 10K may be different for each non-representative terminal group 11H. The reference terminal 10K used for measuring the difference value for one non-representative terminal group 11H may be a terminal of a terminal group 11 different from the one non-representative terminal group. In this embodiment, as an example, the output value from the terminal 10 may be measured as a difference from a reference value (zero as an example). Also, the output value from the terminal 10 may be a value indicated by the magnitude of a voltage.

[0024] Here, the plurality of terminal groups 11 may form at least one chain relationship in which the reference terminal 10K is sequentially used between two or more terminal groups 11. In FIG. 1, as an example, all the terminal groups 11 form one chain relationship in the vertical direction in the figure. When two terminal groups 11 form a chain relationship, the sequential use of the reference terminal 10K between the two terminal groups 11 may mean that, for one terminal group 11, a terminal 10 in the other terminal group 11 is used as the reference terminal 10K. Adjacent terminal groups 11 in the chain relationship may be arranged adjacent to each other in the device under test 100, in other words, may correspond to pixels adjacent to each other in the display.

[0025] When the chain relationship of the terminal groups 11 is formed, the measuring unit 202 may measure the difference value by using any terminal 10 in the other terminal group 11 as the reference terminal 10K for one terminal group 11, respectively, between two adjacent terminal groups 11 in the chain relationship.

[0026] In addition, the measuring unit 202 may further measure the output value of each terminal 10 (also referred to as the representative terminal 10D) in the terminal group 11 (also referred to as the representative terminal group 11D) at one end in each chain relationship. The representative terminal group 11D may be a terminal group 11 different from the non-representative terminal group 11H. The ratio of the representative terminal 10D to all the terminals 10 of the device under test 100 may be, for example, 1 / 64 to 1 / 4.

[0027] In this way, the output value is measured for the terminal 10 in the representative terminal group 11D at one end of the chain relationship, and the reference terminal is sequentially used in the chain relationship to measure the difference value, so that the output value can be calculated for the terminal 10 in each non-representative terminal group 11H included in the chain relationship. In this embodiment, as an example, each of the non-representative terminal groups 11H may be included in any chain relationship. For example, each of the non-representative terminal groups 11H may be included in any one chain relationship. When a plurality of chain relationships are formed including one non-representative terminal group 11H, the one non-representative terminal group 11H may be included in each of the plurality of chain relationships.

[0028] Note that, in order to calculate the output value of the terminal 10 in the non-representative terminal group 11H in the chain relationship, for example, with respect to the difference value of the non-representative terminal 10H in the non-representative terminal group 11H, the difference values measured for the reference terminals 10K in each adjacent non-representative terminal group 11H in sequence on one end side in the chain relationship and the output value measured for the reference terminal in the representative terminal group 11D at one end in the chain relationship may be cumulatively added.

[0029] The measurement unit 202 may supply the measurement result to the determination unit 203. For example, the measurement unit 202 may convert the analog value of the difference value or the signal value into a digital value and supply it to the determination unit 203.

[0030] [1-2-3. Determination Unit 203] The determination unit 203 determines the pass / fail of the device under test 100 based on the measurement results obtained by the measurement unit 202. The determination unit 203 may determine the pass / fail of the device under test 100 based on the measured difference values. For example, the determination unit 203 may determine the pass / fail of the device under test 100 based on whether or not the difference value of each of the non-representative terminals 10H is within a first reference range. Further, the determination unit 203 may further determine the pass / fail of the device under test 100 based on at least one of whether or not the output value of each of the representative terminals 10D is within a second reference range and whether or not the difference value between the output values of each of the representative terminals 10D is within a third reference range. The determination unit 203 may output a determination result indicating the pass / fail of the device under test 100. Note that the determination unit 203 may be realized by software being executed by a processor or the like.

[0031] According to the above test apparatus 200, the difference value between the output value of each terminal 10 in the non-representative terminal group 11H having two or more terminals 10 and the output value of the reference terminal 10K for the non-representative terminal group 11H is measured and the test is performed. Therefore, for two or more terminals 10 in the non-representative terminal group 11H, the difference value can be measured and the test can be performed using the common reference terminal 10 K. Thus, unlike the case where the difference value is measured by sequentially using each terminal 10 as the reference terminal 10K of another terminal 10, the number of times of cumulative addition for calculating the output value from the difference value can be reduced, so that the calculation of the output value can be facilitated. Further, since the number of times of cumulative addition is reduced, the number of output values calculated including the noise generated in the measurement of the difference value and the output value can be reduced, so that the test accuracy when using the calculated output value can be improved.

[0032] In addition, since the test is performed using the measurement result of the difference value, the number of times of measuring the output value, and thus the number of times of measuring an outlier due to the influence of noise, can be reduced, so that the test accuracy can be improved. Further, since it is not necessary to increase the number of measurements for averaging to reduce the influence of outliers, the test time can be shortened.

[0033] In addition, at least one chain relationship is formed in which the reference terminal 10K is sequentially used among two or more terminal groups 11. In each case between two adjacent terminal groups 11 in the chain relationship, for one terminal group 11, any terminal 10 in the other terminal group 11 is used as the reference terminal 10K. Therefore, for each group included in the chain relationship, the output value from the terminal 10 can be calculated sequentially.

[0034] In addition, since the output value of each terminal 10 in the representative terminal group 11D located at one end of each chain relationship is measured, the output value of each terminal 10 in each terminal group 11 included in the chain relationship can be calculated based on the difference value from the output value.

[0035] In addition, since each non-representative terminal group 11H is included in some chain relationship, the output value can be calculated for each terminal 10 in the non-representative terminal group.

[0036] [1-3. Configuration example of the measurement unit 202] Figs. 2 to 4 show the measurement unit 202 together with the terminal 10.

[0037] In this configuration example, as an example, the device under test 100 has 1536 terminals 10. In Figs. 2 to 4, among these, the configuration of the measurement unit 202 for the part where 32 terminals 10 (also referred to as terminals 10 (1) ~Ch (32) connected to ~Ch (1) ~10 (32) are the measurement targets is shown. The measurement unit 202 may have the same configuration for each of the 32 terminals 10 on separate substrates (not shown). The transmission line Ch (n) may supply the output value from each terminal 10 (n) to the measurement unit 202. Note that the numbers 1 to 32 in the parentheses of the subscript in the description such as terminal 10 (1) may indicate the numbers of the corresponding transmission lines Ch. The n in the parentheses of the subscript may indicate any integer from 1 to 32. In this configuration example, the number of terminals 10 and the number of each configuration in the measurement unit 202 may be other numbers.

[0038] Terminal 10 (1) ~10 (32) may be grouped into eight terminal groups 11 (also referred to as terminal groups 11 G1 ~11 G8 ), each containing four terminals 10. Note that the subscripts G1 to G8 indicate the numbers of the terminal groups 11. Also, the number of terminals 10 in each terminal group 11 may correspond to the number of integrated amplification units 220 described later.

[0039] Terminal group 11 G1 ~11 G8 may form a single chain relationship in which the reference terminal 10K is used sequentially. The terminal group 11 at one end of the chain relationship G8 may be the representative terminal group 11D, and the other terminal groups 11 G1 ~11 G7 may be non-representative terminal groups 11H.

[0040] The reference terminal 10K for the terminals 10 G1 within the terminal group 11 (1) ~10 (4) may be a terminal 10 within the terminal group 11 G2 . Similarly, the reference terminal 10K for the terminals 10 (5) within the terminal group 11 G2 ~10 (5) may be a terminal 10 within the terminal group 11 (8) . The reference terminal 10K for the terminals 10 G3 within the terminal group 11 (9) ~10 G3 within the terminal group 11 (9) ~10 (12) may be a terminal 10 within the terminal group 11 G4 . The reference terminal 10K for the terminals 10 (13) within the terminal group 11 G4 ~10 (13) may be a terminal 10 within the terminal group 11 (16) . The reference terminal 10K for the terminals 10 G5 within the terminal group 11 (17) ~10 G5 within the terminal group 11 (17) ~10(20) The reference terminal 10K for G6 may be terminal 10 within the terminal group 11 (21) . The terminal 10 within the terminal group 11 G6 may be terminal 10 within the terminal group 11 (21) ~10 (24) The reference terminal 10K for G7 may be terminal 10 within the terminal group 11 (25) . The terminal 10 within the terminal group 11 G7 may be terminal 10 within the terminal group 11 (25) ~10 (28) The reference terminal 10K for G8 may be terminal 10 within the terminal group 11 (29) .

[0041] The measurement unit 202 may include a plurality of amplification units 220 (also referred to as amplification units 220 (n) ) and a plurality of output units 221 (also referred to as output units 221 (n) ). In this configuration example, as an example, each transmission path Ch may include an amplification unit 220 and an output unit 221. Further, the measurement unit 202 may include one or more switching units 222 (also referred to as switching units 222 (n) ).

[0042] [1-3-1. Amplification Unit 220] Each amplification unit 220 (n) amplifies the difference between the output value from the corresponding terminal 10 (n) and another value. Each amplification unit 220 (n) may supply the amplified value to the corresponding output unit 221 (n) . Each amplification unit 220 may have a variable gain.

[0043] In this configuration example, as an example, each amplification unit 220 (n) may be a differential amplifier such as an operational amplifier, and four of them may be integrated and arranged on a substrate. The non-inverting input terminal of each amplification unit 220 (n) may receive the output value of the corresponding terminal 10 (n) via the corresponding transmission path Ch (n) . For example, in FIG. 2, the amplification units 220 (1) ~220 (4)are integrated, and the non-inverting input terminals thereof are connected to the terminal group 11 (1) ~Ch (4) via the transmission paths Ch G1 within the terminal 10 (1) ~10 (4) output values are input. Similarly, in FIG. 3, the amplification units 220 (5) ~220 (8) are integrated, and the non-inverting input terminals thereof are connected to the terminal group 11 (5) ~Ch (8) via the transmission paths Ch G2 within the terminal 10 (5) ~10 (8) output values are input. And in FIG. 4, the amplification units 220 (29) ~220 (32) are integrated, and the non-inverting input terminal thereof is connected to the terminal group 11 (29) ~Ch (32) via the transmission paths Ch G8 within the terminal 10 (29) ~10 (32) output values are input. In the figure, for simplicity, the inverting input terminals are marked with a circle indicating inversion to distinguish them from the non-inverting input terminals.

[0044] The value input to the inverting input terminal of each amplification unit 220 (n) may be a reference value such as a ground voltage as an example when the output value of the terminal 10 (n) is measured, or may be the output value of the reference terminal 10K when a differential value is measured. These values may be switchable by the switching unit 222 (n) .

[0045] [1-3-2. Output Unit 221] Each output unit 221 (n) outputs a measurement value corresponding to the value amplified by the corresponding amplification unit 220 (n) . In this configuration example, as an example, the output unit 221 may be an AD converter such as 16 bits, convert the amplified analog value into a digital value, and output it as a measurement value. The output unit 221 may supply the measurement value to the determination unit 203.

[0046] [1-3-3. Switching unit 222] One or more switching units 222 (n) switch the measurement mode for the corresponding transmission line Ch (n) for the terminal 10 connected thereto. For example, each switching unit 222 may correspond one-to-one with a terminal in any one of the terminal groups 11, and switch the measurement mode for the terminal 10 in the corresponding terminal group 11. In this configuration example, as an example, the measuring unit 202 has the same number of switching units 222 as the terminals 10 (n) ~10 (1) and can switch the measurement mode for the terminals 10 (32) ~220 (1) in these switching units 222 (32) ~220 (1) in each terminal group 11 (32) ~10 (1) ~10 (32) .

[0047] Each switching unit 222 may switch the measurement mode between at least two of a differential measurement mode for measuring a differential value, a large-amplitude measurement mode for measuring an output value in a first measurement range, and a high-sensitivity measurement mode for measuring an output value in a second measurement range narrower than the first measurement range. Note that in the high-sensitivity measurement mode, the output value may be measured in any one of a plurality (four or five as an example in this configuration example) of the second measurement ranges having equal widths and different upper and lower limit values. Each of the plurality of second measurement ranges may be at least partially included in the first measurement range. Also, the plurality of second measurement ranges may partially overlap each other.

[0048] In this configuration example, as shown in FIGS. 2 and 3 as an example, the terminals 10 of the terminal group 11 G1 ~ G7 , that is, each switching unit 222 corresponding to each non-representative terminal 10H in the non-representative terminal group 11H (1) ~10 (28) ~222 (1) ~222 (28) switch the measurement mode for the terminals 10 G1 ~11 G7 in the terminal group 11 (1) ~10 (28)For each of them, switch which measurement mode to use among the differential measurement mode, the large-amplitude measurement mode, and the high-sensitivity measurement mode. As a result, each switching unit 222 (1) ~222 (28) switches whether to measure the difference value or the output value by each switching unit 222 (1) ~222 (28) may switch between two modes, namely the differential measurement mode and the large-amplitude measurement mode or the high-sensitivity measurement mode. Each switching unit 222 (1) ~222 (28) may further switch which output value to measure within a plurality of second measurement ranges when performing measurement in the high-sensitivity measurement mode.

[0049] Also, as shown in FIG. 4, for each of the terminals 10 G8 of the terminal group 11 (29) ~10 (32) , that is, each switching unit 222 corresponding to each representative terminal 10D within the representative terminal group 11D (29) ~222 (32) may switch which measurement mode to use between the large-amplitude measurement mode and the high-sensitivity measurement mode for each of the terminals 10 G8 within the terminal group 11 (29) ~10 (32) . Each switching unit 222 (29) ~222 (32) may further switch which output value to measure within a plurality of second measurement ranges when performing measurement in the high-sensitivity measurement mode.

[0050] Each switching unit 222 (n) may have a multiplexer 223 (n) and a changing unit 224 (n) and may switch the measurement mode in response to receiving a signal (also referred to as a measurement mode instruction signal) indicating the measurement mode to be applied. The measurement mode instruction signal may be supplied from the test controller 201 to the switching unit 222 according to the condition setting described in the test program by the user.

[0051] [1-3-3(1). Multiplexer 223] Multiplexer 223 (n) switches the connection destination of the inverting input terminal of the corresponding amplifier section 220 (n) in accordance with the measurement mode instruction signal.

[0052] (Multiplexer 223 corresponding to non-representative terminal 10H) Terminal 10 which is non-representative terminal 10H (1) ~10 (28) The multiplexer 223 corresponding to (n) may switch the connection destination between the ground voltage GND, any one of the four reference voltages Vref1 to Vref4, and the transmission path Ch (n) connected to the terminal group 11 of the terminal 10 (terminal 10 in this configuration example as an example) (n) ) and the output value transmission path Ch from the reference terminal 10K associated with the terminal group 11.

[0053] For example, when the multiplexer 223 (n) is instructed to apply the large amplitude measurement mode by the measurement mode instruction signal, the ground voltage GND may be connected to the inverting input terminal of the corresponding amplifier section 220 (n) . As a result, in the amplifier section 220 (n) and the output section 221 (n) , the output voltage of the terminal 10 (n) with the ground voltage GND as a reference can be measured.

[0054] Also, when the multiplexer 223 (n) is instructed to apply the differential measurement mode by the measurement mode instruction signal, the output value transmission path Ch of the reference terminal 10K associated with the terminal group 11 of the corresponding terminal 10 (n) may be connected to the inverting input terminal of the corresponding amplifier section 220 (n) . As a result, in the amplifier section 220 (n) and the output section 221 (n) , the output voltage of the terminal 10 Terminal with the output value of the reference (n) 10K as a reference, that is, the difference value between the output value of the terminal 10 (n) and the output value of the reference terminal 10K can be measured.

[0055] Also, when the application of the high-sensitivity measurement mode is instructed by the measurement mode instruction signal, the multiplexer 223 (n) may connect any one of the reference voltages Vref1 to Vref4 indicated by the measurement mode instruction signal to the inverting input terminal of the corresponding amplifier section 220 (n) . Thereby, in the amplifier section 220 (n) and the output section 221 (n) , the output voltage of the terminal 10 (n) with reference to the reference voltages Vref1 to Vref4 can be measured.

[0056] Here, the reference voltages Vref1 to Vref4 may all be voltages higher than the ground voltage GND and may increase step by step. Thereby, each of the measurement ranges of the output values in the high-sensitivity measurement mode, that is, each of the plurality (here, four) of the second measurement ranges, increases step by step. In this configuration example, as an example, the reference voltages Vref1 to Vref4 are set to fixed values so that the ground voltage GND and the reference voltages Vref1 to Vref4 are equally spaced, but the reference voltages Vref1 to Vref4 may each be variable.

[0057] In this configuration example, as an example, as shown in FIG. 2, the multiplexer 223 (1) ~223 (4) is instructed to apply the differential measurement mode, and the transmission path Ch (1) ~10 (4) of the reference terminal 10 G1 associated with the terminal group 11 (5) of the terminals 10 (5) is connected to the inverting input terminal of the amplifier section 220 (1) ~ 220 (4) .

[0058] Also, as shown in FIG. 3, the multiplexer 223 (5) ~223 (8) is instructed to apply the differential measurement mode, and the reference terminal 10 (5) ~10 (8) associated with the terminal group 11 G2 of the terminals 10(9) transmission path Ch (9) is connected to the inverting input terminal of the amplifier section 220 (5) ~ 220 (8) through

[0059] Subsequently, in the same manner, in this configuration example, the multiplexers 223 (9) ~223 (12) ,223 (13) ~223 (16) ,223 (17) ~223 (20) ,223 (21) ~223 (24) ,223 (25) ~223 (29) are each instructed to apply the differential measurement mode, and the reference terminals 10 G2 ~11 G7 associated with the terminal group 11 (13) ,10 (17) ,10 (21) ,10 (25) ,10 (29) transmission path Ch (13), Ch (17), Ch (21), Ch (25), Ch (29) are each connected to the inverting input terminal of the amplifier section 220 (9) ~220 (12) ,220 (13) ~220 (16) ,220 (17) ~220 (20) ,220 (21) ~220 (24) ,220 (25) ~220 (29) through

[0060] (Multiplexer 223 corresponding to the representative terminal 10D) Representative terminal 10D (29) ~10D (32) The multiplexer 223 corresponding to (n) may switch the connection destination between the ground voltage GND and any one of the five reference voltages Vref11 to Vref15

[0061] For example, the multiplexer 223(n) When the application of the large-amplitude measurement mode is indicated by the measurement mode indication signal, the ground voltage GND may be connected to the inverting input terminal of the corresponding amplifier section 220 (n) Thereby, in the amplifier section 220 (n) and the output section 221 (n) the output voltage of terminal 10 (n) with reference to the ground voltage GND can be measured.

[0062] Also, when the application of the high-sensitivity measurement mode is indicated by the measurement mode indication signal, the multiplexer 223 (n) may connect any one of the reference voltages Vref11 to Vref15 indicated by the measurement mode indication signal to the inverting input terminal of the corresponding amplifier section 220 (n) Thereby, in the amplifier section 220 (n) and the output section 221 (n) the output voltage of terminal 10 (n) with reference to the reference voltages Vref11 to Vref15 can be measured.

[0063] Here, the reference voltages Vref11 to Vref15 may all be voltages higher than the ground voltage GND and may increase step by step. Thereby, the measurement range of the output value in the high-sensitivity measurement mode, that is, each of a plurality (here, five) of the second measurement ranges, increases step by step. In this configuration example, as an example, the reference voltages Vref11 to Vref15 are set to fixed values so that the ground voltage GND and the reference voltages Vref11 to Vref15 are equally spaced, but the reference voltages Vref11 to Vref15 may each be variable. Any one of the reference voltages Vref11 to Vref15 may be equal to any one of the reference voltages Vref1 to Vref4.

[0064] In this configuration example, as an example, as shown in FIG. 4, the multiplexer 223 (29) ~223 (32) is indicated to apply the high-sensitivity measurement mode, and the reference voltage Vref15 is connected to the inverting input terminal of the amplifier section 220 (29) ~220 (32) Here.

[0065] Note that the voltage sources (not shown) for the reference voltages Vref1 to Vref4, Vref11 to Vref15 are not mounted on any of the above-described substrates corresponding to the 32 terminals 10, but are shared among a plurality of substrates, and may be capable of supplying the reference voltages to the inverting input terminals of each amplifier unit 220 on these substrates. Alternatively, the voltage sources for the reference voltages Vref1 to Vref4, Vref11 to Vref15 (1) ~10 (32) are mounted on the above-described substrate corresponding to the 32 terminals 10, and may be capable of supplying the reference voltages Vref1 to Vref4, Vref11 to Vref15 to the inverting input terminals of each amplifier unit 220 (1) ~220 (32) on the substrate. In this case, the reference voltages Vref1 to Vref4, Vref11 to Vref15 may vary according to the ground potential of the substrate.

[0066] [1-3-3(2). Modifying section 224] Modifying section 224 (n) changes the gain of the amplifier unit 220 (n) in accordance with the measurement mode instruction signal. When the large-amplitude measurement mode is applied by the switching section 222 (n) the modifying section 224 (n) may reduce the gain as compared with the case where the large-amplitude measurement mode is not applied (in this configuration example, for example, when the high-sensitivity measurement mode or the differential measurement mode is applied). The gain in the case where the large-amplitude measurement mode is applied may be one-tenth of the gain in the case where other measurement modes are applied. For example, the former gain may be 0.2 and the latter gain may be 2.

[0067] Thereby, when the large-amplitude measurement mode is applied by the switching section 222 (n) that is, when the switching is performed so that the output value is measured within the first measurement range, the gain of the amplifier unit 220 (n) is reduced as compared with the case where the switching is not performed, and as a result, the measurement range in the large-amplitude measurement mode, that is, the first measurement range becomes larger, and measurement over a wide measurement range becomes possible.

[0068] On the one hand, when the high-sensitivity measurement mode is applied by the switching unit 222, that is, when the switching is performed so that the output value is measured within the second measurement range, the gain of the amplifier unit 220 (n) is increased. As a result, high-sensitivity measurement becomes possible. Also, the measurement range in the high-sensitivity measurement mode, that is, each of the four second measurement ranges, is smaller than the measurement range in the large-amplitude measurement mode, that is, the first measurement range. In this embodiment, as described above, each of the plurality of second measurement ranges may increase step by step by the selection of the reference voltages Vref1 to Vref4 by the multiplexer 223, but may all be within the size of the first measurement range. (n)

[0069] Also, when the switching is performed so that the differential measurement mode is applied by the switching unit 222 (n) , the gain of the amplifier unit 220 (n) is increased. As a result, high-sensitivity measurement becomes possible, and the size of the measurement range in the differential measurement mode is the same as the size of the second measurement range.

[0070] According to the above measurement unit 202, for each of the terminals 10 (29) ~10 (32) which are the representative terminals 10D, it is possible to switch between measuring the output value within the first measurement range in the large-amplitude measurement mode and measuring the output value within the second measurement range narrower than the first measurement range in the high-sensitivity measurement mode. Thus, it is possible to surely measure the output value included in the first measurement range and to measure the output value included in the second measurement range with high sensitivity.

[0071] Also, for each of the terminals 10 (1) ~10 (28) which are the non-representative terminals 10H, it is possible to switch between measuring the difference value and measuring the output value. Therefore, for the non-representative terminal 10H, it is possible to measure the output value instead of the difference value as appropriate.

[0072] Also, for the terminals 10 which are the non-representative terminals 10H​(1) ~10 (28) For each of them, it is further switched whether to measure the output value within the first measurement range or to measure the output value within a second measurement range narrower than the first measurement range. Thus, it is possible to surely measure the output value included within the first measurement range for the non-representative terminal 10H and to highly sensitively measure the output value included within the second measurement range.

[0073] Also, when the switching is not performed so that the output value is measured within the first measurement range, the gain is increased, so that highly sensitive measurement can be performed in the high-sensitivity measurement mode and the differential measurement mode. Also, in the high-sensitivity measurement mode and the differential measurement mode, since a largely amplified measurement result is obtained, the noise added to the measurement result can be relatively reduced and the test accuracy can be improved.

[0074] [2. Operation] FIG. 5 shows the operation of the test apparatus 200. The test apparatus 200 tests the device under test 100 by the processes of steps S11 to S29.

[0075] In step S11, the test controller 201 sets the gradation to be output and the output timing for each terminal 10. As an example, when step S11 is performed first, the test controller 201 may set the gradation to the minimum value. When step S11 is performed the second time or later, the test controller 201 may set the gradation to a value one larger than that in the previous step S11. The test controller 201 may set the output timing between the non-representative terminal 10H and its reference terminal 10K as the processing timing of step S13 described later, and set the output timing of the representative terminal 10D as the processing timing of step S15 described later. Thereby, the terminal 10 outputs at the timings of steps S13 and S15.

[0076] In step S13, the measurement unit 202 measures the difference value between the output value of each non-representative terminal 10H in the non-representative terminal group 11H and the output value of the common reference terminal 10K associated with the non-representative terminal group 11H. The measurement unit 202 may use any terminal 10 in the other terminal group 11 as the reference terminal 10K for one of the two adjacent terminal groups 11 in the chain relationship. The measurement unit 202 may measure the difference value between the terminals 10 corresponding to the pixels adjacent to each other in the display among the plurality of terminals 10 of the device under test 100 which is a display driver. The measurement unit 202 may store the difference value of each non-representative terminal 10H in a storage device (not shown).

[0077] In step S15, the measurement unit 202 measures the output value of each representative terminal 10D. The measurement unit 202 may measure the output value of each terminal 10 in the terminal group 11 at one end in each chain relationship. The measurement unit 202 may perform the measurement in the large amplitude measurement mode or the high sensitivity measurement mode. As an example, the measurement unit 202 may perform the measurement in the high sensitivity measurement mode within the second measurement range including the output value measured in the large amplitude measurement mode among the plurality of second measurement ranges after performing the measurement in the large amplitude measurement mode within the first measurement range. The measurement unit 202 may store the output value of each representative terminal 10D in the storage device. Note that the process of step S15 may be performed in parallel and simultaneously with step S13. In this case, the test time is shortened as compared with the case where the processes of steps S13 and S15 are performed in order.

[0078] In step S17, the test controller 201 determines whether the measurement has been performed for all gradations. If it is determined that the measurement has not been performed for one or more gradations (step S17; No), the process may proceed to step S11. Thereby, the output of each gradation is caused to be output to the plurality of terminals 10 by steps S11 to 15 and the measurement is performed. If it is determined that the measurement has been performed for all gradations (step S17; Yes), the process may proceed to step S21.

[0079] In step S21, the determination unit 203 may read the measurement results at each gradation from the storage device, and compare the difference value of the non-representative terminal 10H with the boundary values of the first reference range. The first reference range may be a range represented by the following formula (1) or formula (2). In the formulas, a may be a positive real number. The value of a may be constant regardless of the gradation of the output target when the difference value is measured, or may be different values according to the gradation. -a ≤ difference value ≤ a (Formula (1)) |difference value| ≤ a (Formula (2))

[0080] When the determination unit 203 makes a comparison using formula (1), it may compare the measured plurality of difference values with the upper limit value a and the lower limit value -a of the first reference range respectively, or among the measured plurality of difference values, compare the maximum and minimum difference values with the upper limit value a and the lower limit value -a of the first reference range. Also, when the determination unit 203 makes a comparison using formula (2), it may calculate the absolute values of the measured plurality of difference values and compare them with the upper limit value a of the first reference range respectively, or compare the maximum value of the calculated absolute values with the upper limit value a.

[0081] In step S23, the determination unit 203 may compare the output value of the representative terminal 10D with the boundary values of the second reference range. The second reference range may be a range represented by the following formula (3). Note that in the formula, b and c may be real numbers. The values of b and c may be set according to the gradation of the output target when the output value is measured. b ≤ output value ≤ c (Formula (3))

[0082] The determination unit 203 may compare the measured plurality of output values with the upper and lower limit values b and c of the second reference range respectively, or among the measured plurality of output values, compare the maximum and minimum output values with the upper limit value b and the lower limit value c of the second reference range.

[0083] In step S25, the determination unit 203 may compare the difference value between the output values of the representative terminals 10D with the boundary values of the third reference range. The third reference range may be a range represented by the following formula (4) or formula (5), and the determination unit 203 may perform determination in the same manner as in step S21 described above. In the formula, d may be a positive real number, and may be the same value as a in formulas (1) and (2), or may be a different value. The value of d may be constant regardless of the gradation of the output target when the difference value is measured, or may be a different value according to the gradation. -d ≤ difference value ≤ d (formula (4)) |difference value| ≤ d (formula (5))

[0084] In step S29, the determination unit 203 determines whether the difference value and the output value are within the reference range in each of steps S21 to S25. Thereby, the quality of the device under test 100 is determined based on whether the difference value of each non-representative terminal 10H is within the first reference range. Further, based on whether the output value of each representative terminal 10D is within the second reference range and whether the difference value between the output values of each representative terminal 10D is within the third reference range, the quality of the device under test 100 is determined.

[0085] The determination unit 203 may perform determination based on the measurement results at each gradation. In the present embodiment, as an example, the determination unit 203 may determine whether the difference value and the output value are within the range in each of steps S21 to S25 repeatedly performed for each gradation.

[0086] If it is determined that the difference value and the output value are out of the range in one or more of steps S21 to S25 (step S29; No), the determination unit 203 may output a Fail determination with the device under test 100 being regarded as a defective product. If it is determined that the difference value and the output value are within the range in all of steps S21 to S25 (step S29; Yes), the determination unit 203 may output a Pass determination with the device under test 100 being regarded as a non-defective product.

[0087] According to the above operation, a difference value based on the output value of the reference terminal 10K is measured for each of the non-representative terminals 10H, and the quality of the device under test 100 is determined based on whether the measured difference value is within the first reference range. Therefore, a device under test 100 in which the difference value of the output values between the terminals 10 is outside the first reference range can be regarded as defective. Also, since the test is performed using the measurement results of the difference values, the number of times of measuring the output values, and thus the number of times of measuring outliers due to the influence of noise, can be reduced, so that the test accuracy can be improved. Further, since it is not necessary to increase the number of measurements for averaging to reduce the influence of outliers, the test time can be shortened. Also, since the test can be performed without necessarily obtaining the output values of all the terminals 10 by measurement or calculation, the test time can be further shortened.

[0088] In addition, since the difference value is measured between the terminals 10 corresponding to the pixels adjacent to each other in the display, a device under test 100 in which appropriate output cannot be performed for the adjacent pixels and display unevenness is likely to be recognized can be regarded as defective.

[0089] Further, the output values of each of the representative terminals 10D among the plurality of terminals 10 are further measured, and the quality is further determined based on whether the output value of each of the representative terminals 10D is within the second reference range and whether the difference value between the output values of each of the representative terminals 10D is within the third reference range. Therefore, the test accuracy can be further improved.

[0090] In addition, the difference value between the output value of each of the terminals 10 in the non-representative terminal group 11H having two or more terminals 10 and the output value of the common reference terminal 10K associated with the terminal group 11 is measured and the test is performed. Therefore, for two or more terminals 10 in the non-representative terminal group 11H, a common reference terminal 10Tests can be performed by measuring difference values using K. Therefore, unlike the case where difference values are measured by sequentially using each terminal 10 as a reference terminal 10K for other terminals 10, the number of times of cumulative addition for calculating the output value from the difference value can be reduced, so that the calculation of the output value can be facilitated. In addition, since the number of times of cumulative addition is reduced, the number of output values calculated including noise generated in the measurement of the difference value and the output value can be reduced, so that the test accuracy when using the calculated output value can be improved.

[0091] In addition, at least one chain relationship in which the reference terminal 10K is sequentially used between two or more terminal groups 11 is formed. In each of the two adjacent terminal groups 11 in the chain relationship, any terminal 10 in the other terminal group 11 is used as the reference terminal 10K with respect to one terminal group 11. Therefore, for each group included in the chain relationship, the output value from the terminal 10 can be calculated sequentially.

[0092] In addition, since the output value of each terminal 10 in the representative terminal group located at one end of each chain relationship is measured, the output value of each terminal 10 in each terminal group 11 included in the chain relationship can be calculated based on the difference value from the output value.

[0093] [3. Modification Example] FIG. 6 shows a test system 1A according to Modification Example (1). In this Modification Example (1) and Modification Example (2) described later, components that operate substantially the same as those of the test system 1 shown in FIGS. 1 to 5 are denoted by the same reference numerals, and the description thereof is omitted. The test device 200A of the test system 1A further includes one or more switching units 222A.

[0094] One or more switching units 222A are an example of a third switching unit, and switch which of the plurality of terminals 10 is to be connected to the measurement unit 202. In this configuration example, as an example, a switching unit 222A may be provided for each transmission path Ch in the measurement unit 202, and any one of the plurality of terminals may be selectively connected to the transmission path Ch. In this case, at the same measurement timing, transmission path Ch A plurality of terminals 10 connected thereto may be grouped into a plurality of terminal groups 11. The switching unit 222A may be a multiplexer such as a 4-input 1-output multiplexer.

[0095] In addition, in this modification (1), for the input terminals of the multiplexer 223 in the measurement unit 202 (n) (see FIGS. 2 to 4), a transmission line Ch (m) (where m is any integer from 1 to 32 satisfying n≠m) may be connected instead of at least one of the reference voltages Vref1 to Vref4. Thereby, difference values can be measured in differential measurement mode with more terminals 10 in other terminal groups 11 as the reference terminal 10K.

[0096] According to the above modification (1), since the switching unit 222A switches which of the plurality of terminals 10 is connected to the measurement unit 202, the amplification unit 220 and the output unit 221 can be shared among the plurality of terminals 10, and the configuration of the measurement unit 202 can be simplified.

[0097] FIG. 7 shows a measurement unit 202C according to a modification (2). Note that the measurement unit 202C shown in FIG. 7 is a part for measuring a terminal 10 (n) connected to one transmission line Ch (n) and the measurement unit 202C may have a similar configuration for each transmission line Ch. The measurement unit 202C may include two gain-fixed amplification units 220C (n) , 220D (n) and a switching unit 222C (n) .

[0098] The amplification unit 220C (n) amplifies the difference between the output value from the terminal 10 (n) and the ground voltage and supplies it to the switching unit 222C (n) . The amplification unit 220D (n) amplifies the difference between the output value from the terminal 10 (n) and another value supplied from the multiplexer 223 and supplies it to the switching unit 222C (n) . The other value is the terminal 10 (m) connected to the transmission line Ch(m) It may be the output value, the reference voltages Vref1 to Vref4, or the ground voltage.

[0099] Amplifier section 220D (n) The gain of may be larger than the gain of amplifier section 220C (n) For example, the gain of amplifier section 220D (n) The gain of may be the gain of amplifier section 220C (n) It may be 10 times the gain of. In this modification example, as an example, the gain of amplifier section 220D (n) is 2, and the gain of amplifier section 220C (n) is 0.2.

[0100] Switching section 222C (n) further includes a multiplexer 225 (n) The multiplexer 225 (n) connects either one of the output terminals of amplifier sections 220C (n) , 220D (n) to the output section 221 (n) The multiplexer 225 (n) may perform switching according to the measurement mode instruction signal. When the large-amplitude measurement mode is applied, amplifier section 220C (n) is connected to the output section 221 (n) and when the high-sensitivity measurement mode and the differential measurement mode are applied, amplifier section 220D (n) may be connected to the output section 221 (n)

[0101] Similar to the above-described embodiment, also according to the above modification example (2), when switching is not performed so that the output value is measured within the first measurement range in the large-amplitude measurement mode, the gain is increased, so that measurement is performed with high sensitivity in the high-sensitivity measurement mode and the differential measurement mode. Also, since a largely amplified measurement result is obtained, the noise added to the measurement result can be relatively reduced, and the test accuracy can be improved.

[0102] [4. Other Modification Examples] ​In the above-described embodiments and modifications, one side in the chain relationship of the terminal group 11 was taken as one end, and the terminal group 11 at that one end was described as the representative terminal group 11D. However, the one end side and the other end side in the chain relationship may be reversible. For example, the test apparatus 200 may include a switching unit 222E that reverses one end and the other end in the chain relationship. The switching unit 222E is an example of a second switching unit. Between two adjacent terminal groups 11 in the chain relationship, for each, it may switch whether to use a terminal 10 in one terminal group 11 as a reference terminal 10K for the other terminal group 11, or use a terminal 10 in the other terminal group 11 as a reference terminal 10K for the one terminal group 11. As an example, the switching unit 222E Gi (where i is an integer) corresponding to any terminal 10 (n) in the terminal group 11 Gi is the reference terminal 10K in the two adjacent terminal groups 11 Gi-1 , 11 Gi+1 in the chain relationship Gi-1 , 10K Gi+1 to which the transmission line Ch Gi-1 , Ch Gi+1 can be respectively connected to the inverting input terminals of the amplifier unit 220 (n) . In this case, the test accuracy can be further improved by using the measurement results before and after inversion.

[0103] Also, although the measurement unit 202 has been described as measuring the difference value between the output values of two or more non-representative terminals 10H included in the non-representative terminal group 11H and the output value of the common reference terminal, the difference value may be measured in other modes. For example, the measurement unit 202 may measure the difference value between the output value of a reference terminal 10K different from the terminal 10 and the output value of each of some of the plurality of terminals 10 (also referred to as non-representative terminals 10H) of the device under test 100. As an example, when at least one chain relationship in which each terminal 10 is sequentially used as the reference terminal 10K is formed by the plurality of terminals 10 of the device under test 100, the measurement unit 202 may measure the difference value by using one of the two adjacent terminals 10 in the chain relationship as the non-representative terminal 10H and the other terminal 10 as the reference terminal 10K for the non-representative terminal 10H. Further, in this case, the measurement unit 202 may use one terminal 10 at one end in each chain relationship as the representative terminal 10D and measure its output value.

[0104] Also, although the determination unit 203 has been described as performing pass / fail determination using the difference value for the non-representative terminal 10H, it may also perform determination using the output value calculated from the difference value and the output value of the representative terminal 10D. For example, the determination unit 203 may calculate the output value for each non-representative terminal 10H and further perform determination based on whether the calculated output value is within the reference range.

[0105] Also, although the output value has been described as a value indicated by the magnitude of the voltage, it may also be a value indicated by the magnitude of the current. In this case, the device under test 100 may be an LED driver.

[0106] Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, where the blocks may represent (1) stages of a process in which operations are performed or (2) sections of a device having the role of performing the operations. Particular stages and sections may be implemented by dedicated circuits, programmable circuits supplied with computer-readable instructions stored on a computer-readable medium, and / or processors supplied with computer-readable instructions stored on a computer-readable medium. The dedicated circuits may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. The programmable circuits may include reconfigurable hardware circuits including memory elements such as logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, flip-flops, registers, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), etc.

[0107] A computer-readable medium may include any tangible device capable of storing instructions executable by an appropriate device, such that a computer-readable medium having instructions stored therein will comprise a product including instructions executable to create means for performing the operations specified in the flowchart or block diagram. Examples of computer-readable media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, etc. More specific examples of computer-readable media may include floppy (registered trademark) disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disc (DVD), Blu-ray (RTM) disc, memory stick, integrated circuit card, etc.

[0108] Computer-readable instructions may include any combination of one or more programming languages, including assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or source code or object code written in an object-oriented programming language such as Smalltalk®, JAVA®, C++, and a conventional procedural programming language such as the "C" programming language or a similar programming language.

[0109] Computer-readable instructions may be provided locally or via a wide area network (WAN) such as a local area network (LAN), the Internet, etc., to a processor or programmable circuit of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, and executed to create means for performing the operations specified in a flowchart or block diagram. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc.

[0110] FIG. 8 shows an example of a computer 2200 in which multiple aspects of the present invention may be embodied in whole or in part. Programs installed on the computer 2200 can cause the computer 2200 to function as an operation associated with the apparatus according to an embodiment of the present invention or as one or more sections of the apparatus, or execute the operation or the one or more sections, and / or cause the computer 2200 to execute a process according to an embodiment of the present invention or a stage of the process. Such a program may be executed by the CPU 2212 to cause the computer 2200 to perform specific operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.

[0111] The computer 2200 according to this embodiment includes a CPU 2212, a RAM 2214, a graphic controller 2216, and a display device 2218, which are interconnected by a host controller 2210. The computer 2200 also includes input / output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the host controller 2210 via an input / output controller 2220. The computer also includes legacy input / output units such as a ROM 2230 and a keyboard 2242, which are connected to the input / output controller 2220 via an input / output chip 2240.

[0112] The CPU 2212 operates according to programs stored in the ROM 2230 and the RAM 2214, thereby controlling each unit. The graphic controller 2216 acquires image data generated by the CPU 2212 in a frame buffer provided in the RAM 2214 or the like, or in itself, and causes the image data to be displayed on the display device 2218.

[0113] The communication interface 2222 communicates with other electronic devices via a network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads a program or data from the DVD-ROM 2201 and provides the program or data to the hard disk drive 2224 via the RAM 2214. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0114] The ROM 2230 stores therein a boot program or the like executed by the computer 2200 at activation and / or a program dependent on the hardware of the computer 2200. The input / output chip 2240 may also be connected to the input / output controller 2220 via various input / output units such as a parallel port, a serial port, a keyboard port, a mouse port, etc.

[0115] The program is provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The program is read from the computer-readable medium, installed in the hard disk drive 2224, the RAM 2214, or the ROM 2230, which are also examples of computer-readable media, and executed by the CPU 2212. The information processing described in these programs is read by the computer 2200, resulting in the cooperation between the programs and the various types of hardware resources described above. The apparatus or method may be configured by realizing the operation or processing of information according to the use of the computer 2200.

[0116] For example, when communication is executed between the computer 2200 and an external device, the CPU 2212 may execute a communication program loaded in the RAM 2214 and instruct the communication interface 2222 to perform communication processing based on the processing described in the communication program. The communication interface 2222 reads the transmission data stored in the transmission buffer processing area provided in a recording medium such as the RAM 2214, the hard disk drive 2224, the DVD-ROM 2201, or the IC card under the control of the CPU 2212, transmits the read transmission data to the network, or writes the received data received from the network to the reception buffer processing area or the like provided on the recording medium.

[0117] In addition, the CPU 2212 may cause all or necessary portions of files or databases stored in external recording media such as a hard disk drive 2224, a DVD-ROM drive 2226 (DVD-ROM 2201), an IC card, etc. to be read into the RAM 2214, and may execute various types of processing on the data on the RAM 2214. The CPU 2212 then writes back the processed data to the external recording media.

[0118] Various types of information such as various types of programs, data, tables, and databases may be stored in a recording medium and may be subjected to information processing. The CPU 2212 may perform various types of processing on the data read from the RAM 2214, including various types of operations, information processing, conditional judgments, conditional branches, unconditional branches, information search / replacement, etc. described throughout this disclosure and specified by the instruction sequence of the program, and write back the results to the RAM 2214. Also, the CPU 2212 may search for information in files, databases, etc. within the recording medium. For example, when a plurality of entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, the CPU 2212 searches for an entry that matches the condition where the attribute value of the first attribute is specified from among the plurality of entries, reads the attribute value of the second attribute stored in the entry, and thereby may obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0119] The programs or software modules described above may be stored on a computer-readable medium on or near the computer 2200. Also, a recording medium such as a hard disk or RAM provided within a server system connected to a dedicated communication network or the Internet can be used as a computer-readable medium, thereby providing the program to the computer 2200 via the network.

[0120] As described above, the present invention has been described using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0121] It should be noted that the execution order of each process such as operations, procedures, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is not explicitly indicated as "earlier" or "preceding" etc., and can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the specification, and the drawings, even if it is described using "first," "next," etc. for convenience, it does not mean that it is essential to implement in this order.

Explanation of Reference Numerals

[0122] 1 Test system 10 Terminals 11 Terminal group 100 Device under test 200 Test device 201 Test controller 202 Measurement unit 203 Judgment unit 220 Amplification unit 221 Output unit 222 Switching unit 223 Multiplexer 224 Change unit 225 Multiplexer 2200 Computer 2201 DVD-ROM 2210 Host controller 2212 CPU 2214 RAM 2216 Graphics controller 2218 Display device 2220 Input / output controller 2222 Communication Interface 2224 Hard Disk Drive 2226 DVD-ROM Drive 2230 ROM 2240 Input / Output Chip 2242 Keyboard

Claims

1. For each of some of the plurality of terminals provided in the device under test and outputting single-ended signals, a measuring step of measuring a difference value between the output value of the reference terminal different from the terminal and the output values of the plurality of terminals; A determining step of determining whether the device under test is good or bad based on whether the difference value of each of the some terminals is within a first reference range; Comprising: Among the plurality of terminal groups obtained by grouping the plurality of terminals, at least one chain relationship is formed in which the reference terminal is sequentially used between two or more terminal groups; In the measuring step, a difference value between the output value of each of the terminals in at least one terminal group having two or more terminals among the some terminals and the output value of the common reference terminal associated with the terminal group among the plurality of terminals is measured; In the measuring step, in each of the two adjacent terminal groups in the chain relationship, for one terminal group, any terminal in the other terminal group is used as the reference terminal, a test method.

2. In the measuring step, the output value of each of the terminals in the terminal group at one end in each chain relationship is further measured, the test method according to Claim 1.

3. For each of some of the plurality of terminals provided in the device under test and outputting single-ended signals, a measuring step of measuring a difference value between the output value of the reference terminal different from the terminal and the output values of the plurality of terminals; A determining step of determining whether the device under test is good or bad based on whether the difference value of each of the some terminals is within a first reference range; Comprising: In the measuring step, the output value of each of at least one of the plurality of terminals is further measured; The measuring step is: A first step of measuring the output value of the reference terminal in a first measurement range; A second step of measuring the output value of the reference terminal in a second measurement range narrower than the first measurement range and including the output value measured in the first step; A test method including a step of measuring the output value of the reference terminal by.

4. In the measuring step, the output value of each of at least one of the plurality of terminals is further measured; In the determination step, based on whether the output value of each of the at least one terminal is within a second reference range, and further based on whether the difference value between the output values of each of the at least one terminal is within a third reference range, the quality of the device under test is determined. The test method according to any one of claims 1 to 3.

5. The plurality of terminals form at least one chain relationship in which each terminal is sequentially used as the reference terminal. In the measurement step, between two adjacent terminals in the chain relationship, for one terminal, the other terminal is used as the reference terminal. The test method according to any one of claims 1 to 4.

6. In the measurement step, the output value of a terminal at one end in each chain relationship is further measured. The test method according to claim 5.

7. The device under test can output multiple gradations from each terminal. In the measurement step, the plurality of terminals are caused to output each gradation for measurement. In the determination step, determination is made based on the measurement results at each gradation. The test method according to any one of claims 1 to 6.

8. The device under test is a display driver having the plurality of terminals for controlling a plurality of pixels of a display. The output value is a value indicated by the magnitude of a voltage. The test method according to any one of claims 1 to 7.

9. In the measurement step, among the plurality of terminals, the difference value is measured between terminals corresponding to pixels adjacent to each other within the display. The test method according to claim 8.

10. For each of some of the plurality of terminals provided in the device under test that output single-ended signals, a measurement unit that measures the difference value between the output value of a reference terminal different from the terminal among the plurality of terminals; A determination unit that determines the quality of the device under test based on whether the difference value of each of the some terminals is within a first reference range; Comprising At least one chain relationship is formed in which the reference terminal is sequentially used between two or more terminal groups by the plurality of terminal groups obtained by grouping the plurality of terminals. The measurement unit measures the difference value between the output value of each of the terminals in at least one terminal group having two or more terminals among the some terminals and the output value of a common reference terminal associated with the terminal group among the plurality of terminals. The measurement unit is a test device that, between two adjacent terminal groups in the chain relationship, uses, for one terminal group, any terminal in the other terminal group as the reference terminal.

11. For each of some of the plurality of terminals provided in the device under test that output single-ended signals, a measurement unit that measures a difference value between the output value of the reference terminal different from the terminal and the output value of each of the some terminals among the plurality of terminals; A determination unit that determines whether the device under test is good or bad based on whether the difference value of each of the some terminals is within a first reference range; Comprising: The measurement unit further measures the output value of at least one terminal among the plurality of terminals; The measurement unit: A first step of measuring the output value of the reference terminal in a first measurement range; A second step of measuring the output value of the reference terminal in a second measurement range that is narrower than the first measurement range and includes the output value measured in the first step; A test device that measures the output value of the reference terminal by the above.

12. A computer: For each of some of the plurality of terminals provided in the device under test that output single-ended signals, a measurement unit that measures a difference value between the output value of the reference terminal different from the terminal and the output value of each of the some terminals among the plurality of terminals; A determination unit that determines whether the device under test is good or bad based on whether the difference value of each of the some terminals is within a first reference range Function as: Among the plurality of terminal groups obtained by grouping the plurality of terminals, at least one chain relationship is formed in which the reference terminal is sequentially used between two or more terminal groups; The measurement unit measures a difference value between the output value of each terminal in at least one terminal group having two or more terminals among the some terminals and the output value of the common reference terminal associated with the terminal group among the plurality of terminals; The measurement unit is a program that, between two adjacent terminal groups in the chain relationship, uses, for one terminal group, any terminal in the other terminal group as the reference terminal.

13. A computer: For each of some of the plurality of terminals provided in the device under test that output single-ended signals, a measurement unit that measures a difference value between the output value of the reference terminal different from the terminal and the output value of each of the some terminals among the plurality of terminals; A determination unit that determines whether the test device is good or bad based on whether the difference value of each of the partial terminals is within a first reference range function as The measurement unit further measures the output value of each of at least one of the plurality of terminals The measurement unit a first step of measuring the output value of the reference terminal in a first measurement range; a second step of measuring the output value of the reference terminal in a second measurement range that is narrower than the first measurement range and includes the output value measured in the first step; A program for measuring the output value of the reference terminal by

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