Test Equipment

Abstract

SOLUTION: This testing device includes a measurement unit 202 for measuring a difference value between the output value of each of terminals 10 in at least one terminal group 11 having two or more terminals 10 among a plurality of terminal groups 11 into which a plurality of terminals 10 of a device 100 under test are grouped, and the output value of a reference terminal 10K corresponding to each of the plurality of terminals 10 of the at least one terminal group 11. The plurality of terminal groups 11 form at least one chain relation in which the reference terminal 10K is used in turn among two or more terminal groups 11, and the measurement unit 202 uses, for one terminal group 11, any terminal 10 in the other terminal group 11, as the reference terminal 10K, among two terminal groups 11 that are adjacent to each other in the chain relation.EFFECT: This makes it possible to heighten the accuracy of test and shorten the test time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a test device. [Background technology]

[0002] In Patent Document 1, "The voltage of each output pin is calculated by multiplying the measured voltage difference by the nth voltage measurement unit V un "It is obtained by cumulatively adding the following in order" (paragraph 0007). [Prior art document] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 8-62307 Summary of the Invention

[0003] In a first aspect of the present invention, there is provided a test apparatus, which may include a measurement section that measures a difference between an output value of each terminal in at least one terminal group having two or more terminals among a plurality of terminal groups obtained by grouping a plurality of terminals of a device under test, and an output value of a reference terminal of the plurality of terminals for each of the at least one terminal group.

[0004] The multiple terminal groups may form at least one chain relationship in which a reference terminal is used in turn between two or more terminal groups. Between each of two adjacent terminal groups in the chain relationship, the measurement unit may use any terminal in one terminal group as a reference terminal for the other terminal group.

[0005] The measurement unit may measure the output value of each terminal in the terminal group at one end of each chain relationship.

[0006] The measurement unit may have a switching unit that switches between measuring the output value in a first measurement range and measuring the output value in a second measurement range that is narrower than the first measurement range, for each of the terminals in the terminal group at one end.

[0007] Each of the at least one terminal group may be included in any of the chain relationships.

[0008] The test device may include a second switching unit that reverses one end and the other end of the chain relationship.

[0009] The measurement section may include a switching section that switches between measuring the difference value and measuring the output value for each of the terminals in at least one terminal group.

[0010] The switching unit may switch, for each of the terminals in at least one terminal group, between measuring a differential value, measuring an output value in a first measurement range, or measuring an output value in a second measurement range narrower than the first measurement range.

[0011] The measurement unit may include a plurality of variable-gain amplifiers that amplify the difference between an output value from a corresponding terminal and another value. The measurement unit may include a plurality of output units that output a measurement value corresponding to the amplified value. The gain of each amplifier may be reduced when the switching unit switches so that the output value is measured within the first measurement range compared to when the switching is not performed.

[0012] The test apparatus may include a third switching section that switches which of the multiple terminals is to be connected to the measurement section.

[0013] The test apparatus may include a judging section that judges whether the device under test is good or bad based on the measurement results from the measuring section.

[0014] The device under test may be a display driver having a plurality of terminals for controlling a plurality of pixels of a display, and the output value may be a value indicated by a voltage magnitude.

[0015] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also constitute inventions. [Brief explanation of the drawings]

[0016] [Figure 1] 1 shows a test system 1 according to an embodiment. [Figure 2] The measuring section 202 is shown together with the terminal 10 . [Figure 3] The measuring section 202 is shown together with the terminal 10 . [Figure 4] The measuring section 202 is shown together with the terminal 10 . [Figure 5] 2 shows the operation of the test apparatus 200. [Figure 6] 1 shows a test system 1A according to a modified example (1). [Figure 7] 10 shows a measuring unit 202C according to a modified example (2). [Figure 8] 22 illustrates an example computer 2200 in which aspects of the present invention may be embodied, in whole or in part. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0018] [1. Test System 1] 1 shows a test system 1 according to this 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 multiple terminals 10, and outputs from the terminals 10 are tested by the test apparatus 200. The device under test 100 may be capable of outputting multiple gray levels (for example, 256 gray levels, 1024 gray levels, or 4096 gray levels) from each terminal 10. The device under test 100 may be a display driver having multiple terminals 10 that control multiple pixels of a display (not shown). Each terminal may output a single-ended signal. A single-ended signal may be a signal that expresses a signal value by being high or low relative to a certain reference (for example, zero). Each terminal 10 is associated with one of the display colors that make up the pixels of the display, and the arrangement of the terminals 10 on the device under test 100 may correspond to the arrangement of the corresponding pixels in the display.

[0020] The multiple terminals 10 may be grouped into multiple terminal groups 11 by the test apparatus 200. For example, the multiple terminals 10 may be grouped according to the positions of the terminals 10 within the device under test 100. The terminals 10 included in each terminal group 11 may be located close to each other within the device under test 100. Each terminal group 11 may include at least one terminal 10. The terminal groups 11 may include the same number of terminals 10, or may include different numbers of terminals 10.

[0021] Testing Apparatus 200 The test apparatus 200 tests the quality of the device under test 100. The test apparatus 200 includes a test controller 201, a measuring section 202, and a judging section 203.

[0022] [1-2-1. Test Controller 201] The test controller 201 controls each unit of the test apparatus 200 and causes the device under test 100 to operate in accordance with the test conditions. For example, the test controller 201 may supply a test pattern signal to the device under test 100, causing it to output output values ​​corresponding to specified gradations from at least some of the terminals 10 at desired timings. The output values ​​output from the terminals 10 may be supplied to a transmission path Ch for transmitting the output values. The test controller 201 may be realized by executing software on a processor or the like.

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

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

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

[0026] Furthermore, the measuring section 202 may further measure the output value of each terminal 10 (also referred to as representative terminal 10D) in a terminal group 11 (also referred to as representative terminal group 11D) at one end of 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 representative terminals 10D to all terminals 10 of the device under test 100 may be, for example, 1 / 64 to 1 / 4.

[0027] In this way, an output value is measured for the terminals 10 in the representative terminal group 11D at one end of the chain relationship, and a difference value is measured using the reference terminal in turn in the chain relationship, thereby making it possible to calculate an output value for the terminals 10 in each of the non-representative terminal groups 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 one of the chain relationships. For example, each of the non-representative terminal groups 11H may be included in any one of the chain relationships. When multiple chain relationships are formed including one non-representative terminal group 11H, that one non-representative terminal group 11H may be included in each of the multiple chain relationships.

[0028] To calculate the output value of the terminal 10 in the non-representative terminal group 11H in the chain relationship, for example, the difference value of the non-representative terminal 10H in the non-representative terminal group 11H may be cumulatively added together with the difference values ​​measured for the reference terminal 10K in each of the adjacent non-representative terminal groups 11H in sequence towards one end 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.

[0029] The measurement section 202 may supply the measurement result to the determination section 203. For example, the measurement section 202 may convert the analog values ​​of the difference value and the signal value into digital values ​​and supply the digital values ​​to the determination section 203.

[0030] [1-2-3. Judgment section 203] The judging section 203 judges the acceptability of the device under test 100 based on the measurement results by the measuring section 202. The judging section 203 may judge the acceptability of the device under test 100 based on the measured difference values. For example, the judging section 203 may judge the acceptability of the device under test 100 based on whether or not the difference values ​​of each of the non-representative terminals 10H are within a first reference range. The judging section 203 may also judge the acceptability of the device under test 100 based further 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 judging section 203 may output a judgment result indicating the acceptability of the device under test 100. The judging section 203 may be realized by software being executed by a processor or the like.

[0031] According to the above test apparatus 200, a test is performed by measuring the difference between the output value of each terminal 10 in a non-representative terminal group 11H having two or more terminals 10 and the output value of a reference terminal 10K for the non-representative terminal group 11H. Therefore, for two or more terminals 10 in the non-representative terminal group 11H, a common reference terminal 10 The test can be performed by measuring the differential value using the terminal 10K. Therefore, unlike measuring the differential value by using each terminal 10 in turn as the reference terminal 10K of the other terminals 10, the number of cumulative additions required to calculate the output value from the differential value can be reduced, making it easier to calculate the output value. Furthermore, reducing the number of cumulative additions reduces the number of output values ​​calculated that include noise generated in measuring the differential value and output value, thereby improving the test accuracy when using the calculated output value.

[0032] Furthermore, by conducting a test using the measurement results of the difference value, the number of times the output value is measured and, in turn, the number of times that outliers are measured due to the influence of noise can be reduced, thereby improving test accuracy. Furthermore, since there is no need to increase the number of measurements for averaging to reduce the influence of outliers, the test time can be shortened.

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

[0034] Furthermore, since the output values ​​of each terminal 10 in the representative terminal group 11D located at one end of each chain relationship are measured, the output values ​​of each terminal 10 in each terminal group 11 included in the chain relationship can be calculated by the difference value from the output value.

[0035] Furthermore, since each of the non-representative terminal groups 11H is included in any of the chain relationships, it is possible to calculate the output value for each of the terminals 10 in the non-representative terminal group.

[0036] [1-3. Example of the configuration of the measurement unit 202] 2 to 4 show the measuring unit 202 together with the terminal 10. FIG.

[0037] In this configuration example, the device under test 100 has 1536 terminals 10, and FIGS. 2 to 4 show only the transmission line Ch (1) ~Ch (32) 32 terminals connected to terminal 10 (terminal 10 (1) ~10 (32) The measurement unit 202 may have a similar configuration for each of the 32 terminals 10 on a separate substrate (not shown). (n) Each terminal has 10 (n) The output value from the terminal 10 may be supplied to the measurement unit 202. (1) The numbers 1 to 32 in parentheses of the subscripts in the descriptions above may indicate the number of the corresponding transmission line Ch. The number n in parentheses of the subscripts may indicate any integer from 1 to 32. In this configuration example, the number of terminals 10 and the number of each component in the measuring unit 202 may be other numbers.

[0038] Terminal 10 (1) ~10 (32) There are eight terminal groups 11 (terminal group 11) each containing four terminals 10. G1 ~11 G8 The subscripts G1 to G8 indicate the numbers of the terminal groups 11. The number of terminals 10 in each terminal group 11 may correspond to the number of integrated amplifier sections 220, which will be described later.

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

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

[0041] The measurement unit 202 includes a plurality of amplifiers 220 (amplifiers 220 (n) ) and a plurality of output units 221 (output units 221 (n) In this configuration example, for example, each transmission line Ch may have an amplifier unit 220 and an output unit 221. Also, the measurement unit 202 may have one or more switching units 222 (switching units 222 (n) (also referred to as "interface")

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

[0043] In this configuration example, as an example, each amplifier unit 220 (n) Each amplifier unit 220 may be a differential amplifier such as an operational amplifier, and four amplifier units may be integrated and arranged on a substrate. (n) The non-inverting input terminal of the corresponding transmission line Ch (n) via terminal 10 (n) For example, in FIG. 2, the output value of the amplifier 220 (1) ~220 (4)are integrated, and their non-inverting input terminals are connected to the transmission line Ch (1) ~Ch (4) via terminal group 11 G1 Terminal 10 (1) ~10 (4) Similarly, in FIG. 3, the output value of the amplifier 220 (5) ~220 (8) are integrated, and their non-inverting input terminals are connected to the transmission line Ch (5) ~Ch (8) via terminal group 11 G2 Terminal 10 (5) ~10 (8) 4, the output value of the amplifier 220 (29) ~220 (32) is integrated, and its non-inverting input terminal is connected to the transmission line Ch (29) ~Ch (32) via terminal group 11 G8 Terminal 10 (29) ~10 (32) For simplicity, the inverting input terminal is marked with a circle, which indicates inversion, to distinguish it from the non-inverting input terminal.

[0044] Each amplifier 220 (n) The value input to the inverting input terminal of terminal 10 (n) When the output value of the reference terminal 10K is measured, it may be a reference value such as a ground voltage, for example, and when the difference value is measured, it may be the output value of the reference terminal 10K. (n) The switching may be possible by

[0045] [1-3-2. Output unit 221] Each output unit 221 (n) corresponds to the amplifier 220 (n) The output unit 221 outputs a measurement value corresponding to the value amplified by the amplified signal. In this configuration example, as an example, the output unit 221 may be a 16-bit AD converter or the like, and may 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) is the corresponding transmission channel Ch (n) Terminal 10 connected to (n) For example, each switching unit 222 may correspond one-to-one to a terminal in any one of the terminal groups 11, and may switch the measurement mode for the terminal 10 in the corresponding terminal group 11. (1) ~10 (32) The same number of switching units 222 (1) ~220 (32) These switching units 222 (1) ~220 (32) is terminal 10 in each terminal group 11 (1) ~10 (32) You may switch the measurement mode for

[0047] Each switching unit 222 may switch the measurement mode between at least two of a differential measurement mode in which a differential value is measured, a large amplitude measurement mode in which an output value is measured in a first measurement range, and a high sensitivity measurement mode in which an output value is measured in a second measurement range narrower than the first measurement range. In the high sensitivity measurement mode, the output value may be measured in one of multiple (four or five in this configuration example) second measurement ranges having equal widths but different upper and lower limits. At least a portion of each of the multiple second measurement ranges may be included in the first measurement range. Furthermore, the multiple second measurement ranges may partially overlap each other.

[0048] In this configuration example, as shown in FIGS. 2 and 3, the terminal group 11 G1 ~ G7 Terminal 10 (1) ~10 (28) , that is, each switching unit 222 corresponding to each non-representative terminal 10H in the non-representative terminal group 11H (1) ~222 (28) is the terminal group 11 G1 ~11 G7 Terminal 10 (1) ~10 (28)For each of the above, the switching unit 222 switches between the differential measurement mode, the large amplitude measurement mode, and the high sensitivity measurement mode. (1) ~222 (28) The switching unit 222 switches between measuring the difference value and measuring the output value. (1) ~222 (28) Each switching unit 222 may switch between two modes: a differential measurement mode and a large amplitude measurement mode or a high sensitivity measurement mode. (1) ~222 (28) When performing measurement in high-sensitivity measurement mode, it is possible to further switch in which of the plurality of second measurement ranges the output value is measured.

[0049] Also, as shown in Figure 4, terminal group 11 G8 Terminal 10 (29) ~10 (32) , that is, each switching unit 222 corresponding to each representative terminal 10D in the representative terminal group 11D (29) ~222 (32) is the terminal group 11 G8 Terminal 10 (29) ~10 (32) For each of the above, the switching unit 222 may switch between the large amplitude measurement mode and the high sensitivity measurement mode. (29) ~222 (32) When performing measurement in high-sensitivity measurement mode, it is possible to further switch in which of the plurality of second measurement ranges the output value is measured.

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

[0051] [1-3-3(1).Multiplexer 223] Multiplexer 223 (n) In response to the measurement mode instruction signal, the corresponding amplifier 220 (n) Switches the connection destination of the inverting input terminal.

[0052] (Multiplexer 223 corresponding to non-representative terminal 10H) Terminal 10, which is a non-representative terminal 10H (1) ~10 (28) Multiplexer 223 corresponding to (n) is the ground voltage GND, one of the four reference voltages Vref1 to Vref4, and the corresponding transmission line Ch (n) Terminal 10 (in this configuration example, terminal 10 (n) ) and the transmission path Ch for the output value from the reference terminal 10K associated with the terminal group 11.

[0053] For example, multiplexer 223 (n) When the measurement mode instruction signal instructs application of the large amplitude measurement mode, the corresponding amplifier unit 220 (n) The inverting input terminal of the amplifier 220 may be connected to the ground voltage GND. (n) and output unit 221 (n) Now, let's look at terminal 10, which is referenced to the ground voltage GND. (n) The output voltage can be measured.

[0054] Also, multiplexer 223 (n) When the measurement mode instruction signal indicates that the differential measurement mode is to be applied, the corresponding terminal 10 (n) The transmission path Ch of the output value of the reference terminal 10K associated with the terminal group 11 is connected to the corresponding amplifier unit 220 (n) This allows the amplifier 220 to be connected to the inverting input terminal of the amplifier 220. (n) and output unit 221 (n) So, the criteria Terminals Terminal 10 based on 10K output value (n) The output voltage of terminal 10 (n) The difference between the output value of the reference terminal 10K and the output value of the reference terminal 10K can be measured.

[0055] Also, multiplexer 223 (n) When the application of the high sensitivity measurement mode is instructed by the measurement mode instruction signal, the corresponding amplifier unit 220 (n) The inverting input terminal of the amplifier 220 may be connected to one of the reference voltages Vref1 to Vref4, as instructed by the measurement mode instruction signal. (n) and output unit 221 (n) Now, terminal 10 based on the reference voltages Vref1 to Vref4 (n) The output voltage can be measured.

[0056] Here, the reference voltages Vref1 to Vref4 may all be higher than the ground voltage GND, and may increase in stages. As a result, the measurement range of the output value in the high-sensitivity measurement mode, i.e., each of the multiple (here, four) second measurement ranges, increases in stages. In this configuration 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 shown in FIG. 2, the multiplexer 223 (1) ~223 (4) indicates that differential measurement mode is to be applied, and terminal 10 (1) ~10 (4) Terminal group 11 G1 Reference terminal 10 associated with (5) Transmission channel Ch (5) is the amplifier unit 220 (1) ~ 220 (4) is connected to the inverting input terminal of the

[0058] Also, as shown in FIG. 3, multiplexer 223 (5) ~223 (8) indicates that differential measurement mode is to be applied, and terminal 10 (5) ~10 (8) Terminal group 11 G2 Reference terminal 10 associated with(9) Transmission channel Ch (9) is the amplifier unit 220 (5) ~ 220 (8) is connected to the inverting input terminal of the

[0059] Similarly, in this configuration example, multiplexer 223 (9) ~223 (12) ,223 (13) ~223 (16) ,223 (17) ~223 (20) ,223 (21) ~223 (24) ,223 (25) ~223 (29) The differential measurement mode is specified for each of the terminal groups 11 and 12. G2 ~11 G7 Reference terminal 10 associated with (13) ,10 (17) ,10 (21) ,10 (25) ,10 (29) Transmission channel Ch (13), Ch (17), Ch (21), Ch (25), Ch (29) However, the amplifier unit 220 (9) ~220 (12) ,220 (13) ~220 (16) ,220 (17) ~220 (20) ,220 (21) ~220 (24) ,220 (25) ~220 (29) are connected to the inverting input terminals of the respective

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

[0061] For example, multiplexer 223(n) When the measurement mode instruction signal instructs application of the large amplitude measurement mode, the corresponding amplifier unit 220 (n) The inverting input terminal of the amplifier 220 may be connected to the ground voltage GND. (n) and output unit 221 (n) Now, let's look at terminal 10, which is referenced to the ground voltage GND. (n) The output voltage can be measured.

[0062] Also, multiplexer 223 (n) When the application of the high sensitivity measurement mode is instructed by the measurement mode instruction signal, the corresponding amplifier unit 220 (n) The inverting input terminal of the amplifier 220 may be connected to any one of the reference voltages Vref11 to Vref15 as instructed by the measurement mode instruction signal. (n) and output unit 221 (n) Now, terminal 10 is based on the reference voltages Vref11 to Vref15. (n) The output voltage can be measured.

[0063] Here, the reference voltages Vref11 to Vref15 may all be higher than the ground voltage GND, and may increase in stages. As a result, the measurement range of the output value in the high-sensitivity measurement mode, i.e., each of the multiple (here, five) second measurement ranges, increases in stages. In this configuration 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 of the reference voltages Vref11 to Vref15 may be equal to any of the reference voltages Vref1 to Vref4.

[0064] In this configuration example, as shown in FIG. 4, (29) ~223 (32) The high sensitivity measurement mode is instructed to be applied to the amplifier 220. (29) ~220 (32) is connected to the inverting input terminal of the

[0065] The voltage sources (not shown) of the reference voltages Vref1 to Vref4, Vref11 to Vref15 may be shared among a plurality of substrates without being mounted on any of the above-mentioned substrates corresponding to each of the 32 terminals 10, and may be capable of supplying the reference voltage to the inverting input terminal of each amplifier unit 220 on these substrates. (1) ~10 (32) , and are mounted on the above-mentioned boards corresponding to the respective amplifier units 220 on the boards. (1) ~220 (32) Reference voltages Vref1 to Vref4, Vref11 to Vref15 may be supplied to the inverting input terminals of the transistors 101 to 105. In this case, the reference voltages Vref1 to Vref4, Vref11 to Vref15 may vary depending on the ground potential of the substrate.

[0066] [1-3-3(2). Change 224] Change section 224 (n) In response to the measurement mode instruction signal, the amplifier 220 (n) The gain of the change unit 224 is changed. (n) The switching unit 222 (n) When the large amplitude measurement mode is applied, the gain may be made smaller than when the large amplitude measurement mode is not applied (for example, when the high sensitivity measurement mode or the differential measurement mode is applied in this configuration example). The gain when the large amplitude measurement mode is applied may be one-tenth of the gain when other measurement modes are applied, and for example, the gain in the former may be 0.2 and the gain in the latter may be 2.

[0067] As a result, the switching unit 222 (n) When the large amplitude measurement mode is applied, that is, when switching is performed so that the output value is measured within the first measurement range, the amplifier 220 (n) As a result, the measurement range in the large amplitude measurement mode, that is, the first measurement range, becomes large, and measurement over a wide measurement range becomes possible.

[0068] On the other hand, the switching unit 222 (n) When the high sensitivity measurement mode is applied, that is, when the output value is measured within the second measurement range, the amplifier 220 (n) The gain of the reference voltage Vref1 to Vref4 is increased, thereby enabling high-sensitivity measurement, and the measurement range in the high-sensitivity measurement mode, i.e., each of the four second measurement ranges, is smaller than the measurement range in the large-amplitude measurement mode, i.e., the first measurement range. As described above, in this embodiment, each of the multiple second measurement ranges increases in stages depending on the selection of reference voltages Vref1 to Vref4 by multiplexer 223, but each may be within the first measurement range.

[0069] In addition, the switching unit 222 (n) When the differential measurement mode is switched to be applied by (n) The gain is increased, so that measurements can be made with high sensitivity, and the size of the measurement range in the differential measurement mode is the same as that of the second measurement range.

[0070] According to the above-described measuring unit 202, the terminal 10 which is the representative terminal 10D (29) ~10 (32) For each of the above, the output value is measured within a first measurement range in the large amplitude measurement mode, or the output value is measured within a second measurement range that is narrower than the first measurement range in the high sensitivity measurement mode. This allows the output value within the first measurement range to be measured reliably, and the output value within the second measurement range to be measured with high sensitivity.

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

[0072] In addition, terminal 10H, which is a non-representative terminal,(1) ~10 (28) For each of the above, the output value is further switched between measuring within a first measurement range or measuring within a second measurement range that is narrower than the first measurement range, so that the output value included in the first measurement range for the non-representative terminal 10H can be reliably measured, and the output value included in the second measurement range can be measured with high sensitivity.

[0073] Furthermore, when switching is not performed so that the output value is measured within the first measurement range, the gain is increased, allowing for highly sensitive measurements in the high-sensitivity measurement mode and differential measurement mode. Furthermore, in the high-sensitivity measurement mode and differential measurement mode, the measurement results are acquired with high amplification, making it possible to relatively reduce noise added to the measurement results and improve test accuracy.

[0074] [2. Operation] 5 shows the operation of the test apparatus 200. The test apparatus 200 tests the device under test 100 by performing 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 for the first time, the test controller 201 may set the gradation to the minimum value. When step S11 is performed for the second or subsequent time, the test controller 201 may set the gradation to a value one step larger than the previous value in step S11. The test controller 201 may set the output timing of the non-representative terminal 10H and its reference terminal 10K as the processing timing of step S13, which will be described later, and the output timing of the representative terminal 10D as the processing timing of step S15, which will be described later. As a result, the terminals 10 output at the timings of steps S13 and S15.

[0076] In step S13, the measurement section 202 measures the difference between the output value of each non-representative terminal 10H in the non-representative terminal group 11H and the output value of a common reference terminal 10K associated with the non-representative terminal group 11H. For each of two adjacent terminal groups 11 in a chain relationship, the measurement section 202 may use any one of the terminals 10 in the other terminal group 11 as the reference terminal 10K for one of the terminal groups 11. The measurement section 202 may measure the difference between terminals 10 corresponding to adjacent pixels in the display, among the multiple terminals 10 of the device under test 100, which is a display driver. The measurement section 202 may store the difference value for each of the non-representative terminals 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 one terminal group 11 at one end of 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 large amplitude measurement mode within a first measurement range, and then perform the measurement in the high sensitivity measurement mode within a second measurement range among a plurality of second measurement ranges, the second measurement range including the output value measured in the large amplitude measurement mode. The measurement unit 202 may store the output value of each representative terminal 10D in a storage device. The process of step S15 may be performed simultaneously with step S13. In this case, the test time is shortened compared to when the processes of steps S13 and S15 are performed sequentially.

[0078] In step S17, the test controller 201 determines whether measurements have been performed for all gradations. If it is determined that measurements have not been performed for one or more gradations (step S17; No), the process may proceed to step S11. As a result, measurements are performed by causing the multiple terminals 10 to output each gradation in steps S11 to S15. If it is determined that measurements have 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 out the measurement results for each gradation from the storage device and compare the difference value for the non-representative terminal 10H with the boundary value of a first reference range. The first reference range may be a range expressed by the following formula (1) or formula (2). In the formula, 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 a value that varies depending on the gradation. -a≦difference value≦a (Equation (1)) |Difference value|≦a (Equation (2))

[0080] When making a comparison using formula (1), the determination unit 203 may compare the measured multiple difference values ​​with the upper limit value a and lower limit value -a of the first reference range, respectively, or may compare the maximum and minimum difference values ​​of the measured multiple difference values ​​with the upper limit value a and lower limit value -a of the first reference range.Furthermore, when making a comparison using formula (2), the determination unit 203 may calculate the absolute values ​​of the measured multiple difference values ​​and compare them with the upper limit value a of the first reference range, respectively, or may compare the maximum 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 value of a second reference range. The second reference range may be a range expressed 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 (Equation (3))

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

[0083] In step S25, the determination unit 203 may compare the difference between the output values ​​of the representative terminal 10D with the boundary value of a third reference range. The third reference range may be a range expressed by the following equation (4) or equation (5), and the determination unit 203 may make a determination in the same manner as in step S21 described above. In the equations, d may be a positive real number and may be the same as or different from a in equations (1) and (2). 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 value that varies depending on the gradation. -d≦difference value≦d (Equation (4)) |Difference value|≦d (Equation (5))

[0084] In step S29, the judging section 203 judges whether the difference values ​​and output values ​​are within the reference ranges in each of steps S21 to S25. As a result, the pass / fail of the device under test 100 is judged based on whether the difference values ​​of each of the non-representative terminals 10H are within the first reference range. In addition, the pass / fail of the device under test 100 is judged further 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 a third reference range.

[0085] The determination unit 203 may make a determination based on the measurement results for each gradation. In the present embodiment, as an example, the determination unit 203 may determine whether or not the difference value or the output value is within a range in each of steps S21 to S25 that are repeatedly performed for each gradation.

[0086] If it is determined that the difference value or the output value is out of range in one or more steps of steps S21 to S25 (step S29; No), the judging section 203 may output a Fail judgment, deeming the device under test 100 to be defective. If it is determined that the difference value or the output value is within range in all steps S21 to S25 (step S29; Yes), the judging section 203 may output a Pass judgment, deeming the device under test 100 to be non-defective.

[0087] According to the above-described operation, a differential value is measured for each of the non-representative terminals 10H relative to the output value of the reference terminal 10K, and the quality of the device under test 100 is determined based on whether the measured differential value is within the first reference range. Therefore, a device under test 100 in which the differential value of the output values ​​between the terminals 10 falls outside the first reference range can be determined to be defective. Furthermore, by performing testing using the differential value measurement results, the number of times output values ​​are measured and, ultimately, the number of times outliers are measured due to noise can be reduced, thereby improving test accuracy. Furthermore, since there is no need to increase the number of measurements for averaging to reduce the influence of outliers, test time can be shortened. Furthermore, since testing can be performed without necessarily obtaining the output values ​​of all terminals 10 by measurement or calculation, test time can be further shortened.

[0088] Furthermore, since the difference value is measured between the terminals 10 corresponding to adjacent pixels in the display, it is possible to classify the device under test 100 as defective if it is unable to provide appropriate output to adjacent pixels and therefore display unevenness is easily noticeable.

[0089] Furthermore, the output value of each representative terminal 10D among the multiple terminals 10 is further measured, and the pass / fail determination is further based on whether the output value of each representative terminal 10D is within a second reference range and whether the difference value between the output values ​​of each representative terminal 10D is within a third reference range, thereby further improving the test accuracy.

[0090] Furthermore, the test is performed by measuring the difference between the output value of each terminal 10 in a non-representative terminal group 11H having two or more terminals 10 and the output value of a common reference terminal 10K associated with the terminal group 11. Therefore, for two or more terminals 10 in the non-representative terminal group 11H, 10The test can be performed by measuring the differential value using the terminal 10K. Therefore, unlike measuring the differential value by using each terminal 10 in turn as the reference terminal 10K of the other terminals 10, the number of cumulative additions required to calculate the output value from the differential value can be reduced, making it easier to calculate the output value. Furthermore, reducing the number of cumulative additions reduces the number of output values ​​calculated that include noise generated in measuring the differential value and output value, thereby improving the test accuracy when using the calculated output value.

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

[0092] Furthermore, since the output values ​​of each terminal 10 in the representative terminal group located at one end of each chain relationship are measured, the output values ​​of each terminal 10 in each terminal group 11 included in the chain relationship can be calculated by the difference value from the measured output value.

[0093] [3. Modifications] Fig. 6 shows a test system 1A according to modified example (1). In this modified example (1) and modified example (2) described later, parts that operate in substantially the same manner as those in the test system 1 shown in Figs. 1 to 5 are given the same reference numerals, and descriptions thereof will be omitted. The test apparatus 200A of the test system 1A further includes one or more switching units 222A.

[0094] The one or more switching units 222A are an example of a third switching unit, and switch which of the multiple terminals 10 is connected to the measurement unit 202. In this configuration example, as an example, the measurement unit 202 may be provided with a switching unit 222A for each transmission path Ch, and each of the multiple terminals may be selectively connected to the transmission path Ch. In this case, the transmission paths C may be connected at the same measurement timing.h A plurality of terminals 10 connected to the terminals 10 may be grouped into a plurality of terminal groups 11. The switching unit 222A may be a multiplexer with four inputs and one output.

[0095] In this modification (1), the multiplexer 223 in the measurement unit 202 (n) (See Figures 2 to 4) for the input terminal, instead of at least one of the reference voltages Vref1 to Vref4, the transmission line Ch (m) (where m is any integer between 1 and 32 satisfying n≠m) may be connected. This makes it possible to measure the difference value in the differential measurement mode using more terminals 10 in other terminal groups 11 as reference terminals 10K.

[0096] According to the above-described variant example (1), the switching unit 222A can switch which of the multiple terminals 10 is connected to the measurement unit 202, so that the amplification unit 220 and the output unit 221 can be shared among the multiple terminals 10, thereby simplifying the configuration of the measurement unit 202.

[0097] 7 shows a measuring unit 202C according to the modified example (2). The measuring unit 202C shown in FIG. 7 measures one transmission line Ch (n) Terminal 10 connected to (n) The measurement unit 202C may have the same configuration for each transmission line Ch. The measurement unit 202C includes two fixed gain amplifiers 220C. (n) ,220D (n) and the switching unit 222C (n) and

[0098] Amplifier 220C (n) Terminal 10 (n) The difference between the output value from the switching unit 222C and the ground voltage is amplified. (n) The amplifier 220D (n) Terminal 10 (n) The difference between the output value from the multiplexer 222 and another value supplied from the multiplexer 223 is amplified and sent to the switching unit 222C. (n) Other values ​​are supplied to the transmission line Ch (m) Terminal 10 connected to(m) The output value may be the reference voltages Vref1 to Vref4, or the ground voltage.

[0099] Amplification unit 220D (n) The gain of the amplifier 220C (n) The gain of the amplifier unit 220D may be larger than that of the amplifier unit 220D. (n) The gain of the amplifier 220C (n) In this modification, the gain may be 10 times that of the amplifier 220D. (n) The gain is 2, the amplifier section 220C (n) The gain is 0.2.

[0100] Switching unit 222C (n) is a multiplexer 225 (n) The multiplexer 225 further includes: (n) is the amplifier unit 220C (n) ,220D (n) Either one of the output terminals is connected to the output unit 221 (n) Connect to Multiplexer 225 (n) may be switched in response to a measurement mode instruction signal, and when the large amplitude measurement mode is applied, the amplifier unit 220C (n) The output unit 221 (n) When the high sensitivity measurement mode and the differential measurement mode are applied, the amplifier 220D (n) The output unit 221 (n) You may connect to

[0101] In the above modification (2), similarly to the above embodiment, when the large amplitude measurement mode is not switched so that the output value is measured within the first measurement range, the gain is increased, so that measurements are performed with high sensitivity in the high sensitivity measurement mode and the differential measurement mode. Furthermore, since the measurement results are acquired with high amplification, the noise added to the measurement results is relatively small, thereby improving test accuracy.

[0102] [4. Other Modifications] In the above embodiment and modified example, one side of the chain relationship of the terminal groups 11 is described as one end, and the terminal group 11 at that end is described as the representative terminal group 11D, but the one end and the other end in the chain relationship may be reversed. For example, the test apparatus 200 may include a switching unit 222E that reverses the one end and the other end in the chain relationship. The switching unit 222E is an example of a second switching unit, and may switch between two adjacent terminal groups 11 in the chain relationship whether a terminal 10 in one terminal group 11 is used as a reference terminal 10K for the other terminal group 11, or whether a terminal 10 in the other terminal group 11 is used as a reference terminal 10K for the one terminal group 11. As an example, Gi (where i is an integer) (n) The switching unit 222E corresponding to Gi is the terminal group 11 on both sides in the chain relationship. Gi-1 ,11 Gi+1 Reference terminal 10K Gi-1 ,10K Gi+1 Transmission line Ch connected to Gi-1 ,Ch Gi+1 and the amplifier 220 (n) In this case, the test accuracy can be further improved by using the measurement results before and after inversion.

[0103] In addition, although the determination unit 203 has been described as determining pass / fail using the difference value for the non-representative terminal 10H, the determination may also be made using an output value calculated from the difference value and the output value of the representative terminal 10D. For example, the determination unit 203 may calculate an output value for each of the non-representative terminals 10H, and may also make a determination based on whether the calculated output value is within a reference range.

[0104] Although the output value has been described as a value indicated by the magnitude of a voltage, it may be a value indicated by the magnitude of a current, in which case the device under test 100 may be an LED driver.

[0105] 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 an apparatus responsible for performing the operations. Particular stages and sections may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable medium, and / or a processor provided with computer-readable instructions stored on a computer-readable medium. Dedicated circuitry may include digital and / or analog hardware circuitry, and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuitry may include reconfigurable hardware circuitry, including logical AND, OR, XOR, NAND, NOR, and other logical operations, flip-flops, registers, memory elements such as field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and the like.

[0106] A computer-readable medium may include any tangible device capable of storing instructions that are executed by an appropriate device, such that the computer-readable medium having instructions stored thereon comprises an article of manufacture containing instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable media may include electronic, magnetic, optical, electromagnetic, and semiconductor storage media. More specific examples of computer-readable media may include floppy 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, and the like.

[0107] The computer readable instructions may include either assembler instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages ​​such as the “C” programming language or similar programming languages.

[0108] The computer-readable instructions may be provided to a processor or programmable circuitry of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, either locally or over a wide-area network (WAN) such as a local area network (LAN), the Internet, etc., which executes the computer-readable instructions to create means for performing the operations specified in the flowcharts or block diagrams. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc.

[0109] 8 illustrates an example of a computer 2200 in which aspects of the present invention may be embodied, in whole or in part. Programs installed on the computer 2200 may cause the computer 2200 to function as or perform operations associated with an apparatus or one or more sections of the apparatus according to embodiments of the present invention, and / or to perform a process or steps of a process according to embodiments of the present invention. Such programs may be executed by the CPU 2212 to cause the computer 2200 to perform specific operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

[0110] A computer 2200 according to this embodiment includes a CPU 2212, a RAM 2214, a graphics 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.

[0111] The CPU 2212 operates according to programs stored in the ROM 2230 and RAM 2214, thereby controlling each unit. The graphics controller 2216 acquires image data generated by the CPU 2212 into a frame buffer or the like provided in the RAM 2214 or into the graphics controller 2216 itself, and causes the image data to be displayed on the display device 2218.

[0112] The communications 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 programs or data from the DVD-ROM 2201 and provides the programs 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.

[0113] The ROM 2230 stores therein a boot program or the like that is executed by the computer 2200 upon activation, and / or programs that depend on the hardware of the computer 2200. The input / output chip 2240 may also connect various input / output units to the input / output controller 2220 via a parallel port, a serial port, a keyboard port, a mouse port, etc.

[0114] The programs are provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The programs are read from the computer-readable medium, installed in the hard disk drive 2224, RAM 2214, or ROM 2230, which are also examples of computer-readable media, and executed by the CPU 2212. Information processing described in these programs is read by the computer 2200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be configured by realizing information manipulation or processing in accordance with the use of the computer 2200.

[0115] For example, when communication is performed between the computer 2200 and an external device, the CPU 2212 may execute a communication program loaded into the RAM 2214 and instruct the communication interface 2222 to perform communication processing based on the processing described in the communication program. Under the control of the CPU 2212, the communication interface 2222 reads transmission data stored in a transmission buffer processing area provided in the RAM 2214, the hard disk drive 2224, the DVD-ROM 2201, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes reception data received from the network to a reception buffer processing area or the like provided on the recording medium.

[0116] The CPU 2212 may also cause all or a necessary portion of a file or database stored on an external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM 2201), an IC card, etc. to be read into the RAM 2214, and perform various types of processing on the data on the RAM 2214. The CPU 2212 then writes back the processed data to the external recording medium.

[0117] Various types of information, such as various types of programs, data, tables, and databases, may be stored on the recording medium and may undergo information processing. The CPU 2212 may perform various types of processing on data read from the RAM 2214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequences of the programs, and write the results back to the RAM 2214. The CPU 2212 may also search for information in a file, database, etc. on the recording medium. For example, if multiple entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored on the recording medium, the CPU 2212 may search for an entry that matches a condition specified by the attribute value of the first attribute from among the multiple entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0118] The above-described programs or software modules may be stored in a computer-readable medium on or near the computer 2200. A recording medium such as a hard disk or RAM provided in a server system connected to a dedicated communication network or the Internet can also be used as a computer-readable medium, thereby providing the programs to the computer 2200 via the network.

[0119] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0120] 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, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0121] 1 Test System 10 terminals 11 Terminal Groups 100 devices under test 200 Test Equipment 201 Test Controller 202 Measuring section 203 Judgment section 220 Amplification Unit 221 Output section 222 Switching section 223 Multiplexer 224 Changes 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 I / O chip 2242 keyboard

Claims

1. a measurement unit that measures a difference between an output value of each terminal in at least one terminal group having two or more terminals among a plurality of terminal groups obtained by grouping a plurality of terminals that the device under test has, and an output value of a reference terminal for each of the plurality of terminals in the at least one terminal group; Equipped with the plurality of terminal groups form at least one chain relationship in which the reference terminal is used in turn between two or more terminal groups, The test device wherein the measurement unit uses, for one of two adjacent terminal groups in the chain relationship, any terminal in the other terminal group as the reference terminal.

2. 2. The test apparatus according to claim 1, wherein the measurement section measures the output value of each terminal in a terminal group at one end of each chain relationship.

3. 3. The test apparatus according to claim 2, wherein the measurement section includes a switching section that switches between measuring an output value in a first measurement range and measuring an output value in a second measurement range that is narrower than the first measurement range, for each of the terminals in the terminal group at the one end.

4. The test apparatus according to claim 1 , wherein each of the at least one terminal group is included in one of the chain relationships.

5. The test apparatus according to claim 1 , further comprising a second switching unit that inverts one end and the other end of the chain relationship.

6. a measurement unit that measures a difference between an output value of each terminal in at least one terminal group having two or more terminals among a plurality of terminal groups obtained by grouping a plurality of terminals that the device under test has, and an output value of a reference terminal for each of the plurality of terminals in the at least one terminal group; Equipped with The test apparatus, wherein the measurement section includes a switching section that switches between measuring the difference value and measuring the output value for each of the terminals in the at least one terminal group.

7. 7. The test apparatus according to claim 6, wherein the switching unit switches, for each of the terminals in the at least one terminal group, between measuring the difference value, measuring the output value in a first measurement range, and measuring the output value in a second measurement range narrower than the first measurement range.

8. The measurement unit a plurality of variable gain amplifiers that amplify the difference between an output value from a corresponding terminal and another value; a plurality of output units that output measurement values ​​corresponding to the amplified values; and 8. The test apparatus according to claim 3, wherein the gain of each amplifier unit is made smaller when the switching unit is switching so that the output value is measured within the first measurement range, compared to when the switching unit is not switching.

9. The test apparatus according to claim 1 , further comprising a third switching unit that switches which of the plurality of terminals is to be connected to the measurement unit.

10. 10. The test apparatus according to claim 1, further comprising a judging section that judges whether the device under test is good or bad based on a measurement result by the measuring section.

11. the device under test is a display driver having the plurality of terminals for controlling a plurality of pixels of a display, The test apparatus according to claim 1 , wherein the output value is a value indicated by a magnitude of a voltage.

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