WO2004046737A1

WO2004046737A1 - High speed measuring system of resistance

Info

Publication number: WO2004046737A1
Application number: PCT/KR2002/002288
Authority: WO
Inventors: Duk-Hyun Ryu
Original assignee: Wintec Co. Ltd.
Priority date: 2002-11-15
Filing date: 2002-12-05
Publication date: 2004-06-03
Also published as: KR20040042616A; AU2002368360A1

Abstract

A high-speed resistance measurement system. The system automatically measures individual resistances of a plurality of resistors connected to individual probes by switching on/off individual currents flowing into the probes in a process for determining whether the resistors are shorted or open and a resistor-trimming process for a target resistance. The system includes a host computer for outputting a measured result according to a control command from an inspector, and a main resistance measurement unit for automatically performing the open/short inspection or the trimming process on the plurality of resistors according to the control command received at the host computer, and transmitting result data to the host computer, such that a plurality of resistances can be measured at high speed in a display panel's fabrication process or a resistor trimming process, resulting in reduction of the costs of production and the required manpower in the manufacturing lines. In addition, the system enhances the accuracy of measured resistances, reduces the number of defective products, and thus enhances reliability of the products.

Description

HIGH SPEED MEASURING SYSTEM OF RESISTANCE

Technical Field

The present invention relates to a high-speed resistance measurement system, and more particularly to a high-speed resistance measurement system for automatically measuring individual resistances of a plurality of resistors connected to individual probes by switching on/off individual currents flowing into the probes in a process for determining whether the resistors are shorted or open and a resistor-trimming process for a target resistance, such that it is applicable to a variety of fabrication processes of electronic appliances such as a PDP (Plasma Display Panel) implemented with many resistors.

Background Art

A conventional manual resistance meter and a conventional resistance measuring method using the same will hereinafter be described with reference to Figs. 1~3, wherein a PDP fabrication process is adapted as a first example and a resistor trimming process is adapted as a second example.

Fig. 1 is a view illustrating an open/short tester scheme for a PDP using the conventional manual resistance meter. Fig. 2 is a flow chart illustrating a process for checking an open state of the PDP using the conventional manual resistance meter. Fig. 3 is a flow chart illustrating a process for checking a short state of the PDP using the conventional manual resistance meter.

With the increasing development of the next generation display technologies, many developers have conducted intensive research into the PDP having a large-sized screen and a thin thickness, such that it is expected that the PDP will be increasingly applicable to a variety of electronic appliances such as a wall TV, a monitor for workstations, etc. The PDP operates in the following manner. An inert gas mixture such as a mixture of He (Helium) and Ne (Neon) and a mixture of Ne and Xe (Xenon) is injected into a space sealed by upper and lower glasses and other spaces sealed by a compartment therebetween, plasma is created by the discharge of the inert gas to generate UV (Ultraviolet) light, and the UV light excites a fluorescent material such that an energy level of the fluorescent material drops from an excited state to a ground state. In this case, visible light is created by an energy difference between the two states, and therefore, the PDP can display an image thereon using the visible light.

The PDP contains a plurality of grooves formed at predetermined intervals to create the discharge space between the transparent upper and lower glasses, and a plurality of address electrodes are located on the grooves. Sustain and scan electrodes are located on the upper glass at predetermined intervals, and a sustain discharge mechanism is repeated by a voltage applied to the electrodes such that light is emitted from the inside of the glasses to form an image on the PDP. However, the aforementioned PDP fabrication process has been manually performed, resulting in a very long manufacturing time and a great number of employees in the manufacturing lines. Thus, in the current domestic PDP manufacturing process, the daily production rate is not enough to meet the demand of consumers such that the PDPs are too expensive for common consumers to purchase them. Particularly, in a conventional product inspection process of the PDPs each having many electrodes, there has been typically used a manual inspection for determining whether an image is normally formed on each PDP to distinguish any defective electrode among many electrodes, which is illustrated in Fig. 1. In order to detect a defective electrode caused by a foreign substance or faulty connection between the electrodes, an open/short inspection is performed by connecting probes of a manual resistance meter to any electrodes causing an abnormal image. When the irregular display region on the PDP is not specified or is too wide to manually check, the number of electrodes required to be manually inspected may be several hundreds to several tens of thousands. In the case where a disconnection or faulty area is found on an electrode

499 and a voltage is applied to the electrode 499, and two ends of the electrode 499 are insulated by the disconnection region or the faulty connection region, such that the electrode 499 is turned off even though a current is applied thereto. In more detail, because the disconnection or faulty area serves as an immense resistance to inhibit a current flow, an inspector performs an open inspection of the electrode 499 by connecting probes 11a and lib of the resistance meter 10 to two ends of the electrodes 499, respectively.

In an open inspection method for the electrodes, as shown in Fig. 2, in the case where equipment for inspecting electrodes in a PDP glass is prepared at step Al, probes of a resistance meter are manually brought into contact with two ends of any doubtful electrode estimated to be a defective electrode to measure resistance between the two ends at step A2.

If the resistance between the two ends is higher than a predetermined reference immense-resistance value of 2MΩ at step A3, the electrode is determined to be in an open state at step A4, and an inspector records an electrode number "499" of the opened electrode to replace it at a later time. If the measured resistance is lower than the reference immense-resistance value of 2MΩ, the electrode is determined to be in a normal state at step A6. It is determined at step A7 whether the measured electrode is a final electrode among electrodes to be inspected. If the measured electrode is the final electrode at step A7, the open inspection for electrodes is finished. If the measured electrode is not the final electrode at step A7, the open inspection is repeated for the next electrode.

If the open inspection is finished, then an electric short inspection is performed to determine a risk of element breakage caused by an overcurrent flowing into different electrodes, wherein the overcurrent occurs due to a fine dust, a foreign substance, etc., existing between the electrodes. To this end, the inspector connects the probes 11a' and 12a' of the resistance meter 10' to the two different electrodes 494 and 495, respectively, to measure a resistance therebetween. If such an electric short occurs between the two electrodes 494 and 495, a current flows therebetween, resulting in an infinitesimal resistance close to zero.

In such a short inspection method, as shown in Fig. 3, in the case where equipment for inspecting electrodes in a PDP glass is prepared at step Bl, probes of a resistance meter are manually brought into contact with two doubtful electrodes estimated to be defective in order to measure a resistance between the two electrodes at step B2.

If the resistance between the two ends is lower than a predetermined reference infinitesimal- resistance value of 200Ω at step B3, the electrode is determined to be in a short state at step B4, and an inspector records numbers 494 and 495 of the shorted electrodes to replace them at a later time. If the measured resistance is higher than the reference infinitesimal-resistance value of 200Ω, the electrode is determined to be in a normal state at step B6. It is determined at step B7 whether the measured electrode is a final electrode among electrodes to be inspected. If the measured electrode is the final electrode at step B7, the short inspection for electrodes is finished. If the measured electrode is not the final 02 002288

electrode at step B7, the short inspection is repeated for the next electrode.

In a conventional resistor-trimming process, a carbon film of a resistor formed on a ceramic board is trimmed with a laser device emitting a laser beam so that a resistance of the resistor varies until it reaches a target resistance. To this end, a Wheatstone bridge circuit is provided as shown in Fig. 4, and a resistor- trimming process is performed using a manual resistance meter.

The Wheatstone bridge circuit is configured such that a resistor having a target resistance Rref is disposed as shown in Fig. 4 and a laser device 50 emitting a laser beam is positioned over a resistor Rtrim to be trimmed so that the laser beam is directed to the resistor Rtrim in a direction perpendicular to the resistor Rtrim. The laser device 50 emits the laser beam to trim the carbon film of the resistor Rtrim, and, as the resistor Rtrim is trimmed, the resistance of the resistor Rtrim increases to reach the target resistance Rref. By connecting the probes 11a and lib of the manual resistance meter 10 to the two ends of the trimming resistor Rtrim, the inspector can check whether the resistance of the resistor Rtrim reaches the target resistance.

According to characteristics of the Wheatstone bridge circuit, when Rref = Rtrim, a voltage difference between two ends of a current meter 60 is 0. Thus, when the current meter 60 indicates a current of 0A, the laser device 50 is turned off to terminate the process of trimming the resistor Rtrim. Now, such a resistor trimming method will be hereinafter described with reference to a flow chart shown in Fig. 5.

First, the resistor Rref having the target resistance is connected to the Wheatstone bridge circuit at step CI, and the resistor Rtrim to be trimmed is connected to the Wheatstone bridge circuit at step C2.

The probes of the manual resistance meter are manually brought into contact with the two ends of the resistor Rtrim to measure its initial resistance and continuously measure its variable resistance at step C3. The laser device is activated to trim the resistor Rtrim at step C4, and the inspector checks whether a current value indicated by the current meter reaches 0A at step C5. If the checked result is that no current flows through the current meter, the laser device 50 stops its operation to stop the trimming process at step C6. If a current is detected by the current meter 60, the laser device 50 maintains its operation to continuously trim the resistor Rtrim. However, in such a conventional resistor trimming process, it is necessary to provide a passive circuitry configuration for implementing the trimming process. Particularly, when employing a laser device, the laser beam causes a temperature variation during the trimming process, thereby lowering the accuracy of the resistor. In addition, since the resistance is measured using the manual resistance meter, it is difficult to accurately measure the resistance trimmed on the basis of the target resistance. Moreover, the conventional trimming process can be applied to a single resistor or a Y-shaped resistor, but it cannot be applied to delta (or triangular connection) type resistors that are connected to three power sources, which are 120 degrees apart from each other, to generate three-phase loads, resulting in the limitation of the application range. The productivity is also lowered because it is necessary to purchase equipment for application to the delta type resistors.

As stated above, the first and second examples using the conventional resistance meter involve manual open/short inspections for resistors, and a considerable manpower and time is thus required in determining whether each of many PDP electrodes is defective, thereby increasing the manufacturing cost. In addition, when trimming a resistor by a laser device, a manual resistance meter cannot accurately measure the resistance value of the resistor that minutely varies by the laser device, and therefore, its error range of the resistor increases, and the accuracy of chips, electrodes, etc., implemented with the resistor is also lowered.

^"Disclosure of the Invention

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a high-speed resistance measurement system for measuring individual resistances of a plurality of resistors connected to individual probes by switching on/off individual currents flowing into the probes in a process for determining whether the resistors are shorted or open and a resistor-trimming process for a target resistance, storing and displaying the measured resistances to implement an automated resistor inspection, and precisely measuring each resistance in a process of trimming various types of resistors to reduce an error range between the measured resistance and a target resistance, resulting in a guaranteed reliability of products, an automated production process for detecting a defective resistor and measuring each resistance of the resistors, and the improvement of productivity.

In accordance with the present invention, the above and other objects can be accomplished by the provision of a high-speed resistance measurement system, including a host computer for receiving an entry control command adapted to automatically perform an open/short inspection or a trimming process, and outputting result data according to the control command, and a main resistance measurement unit for automatically performing the open/short inspection or the trimming process on the plurality of resistors according to the control command received at the host computer, and transmitting result data to the host computer.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a view illustrating an open/short tester for a PDP using the conventional manual resistance meter;

Fig. 2 is a flow chart illustrating a process for checking an open state of the PDP using the conventional manual resistance meter; Fig. 3 is a flow chart illustrating a process for checking a short state of the

PDP using the conventional manual resistance meter;

Fig. 4 is a view illustrating a resistor-trimming apparatus using the conventional manual resistance meter;

Fig. 5 is a flow chart illustrating a resistor-trimming process using the conventional manual resistance meter;

Fig. 6 is a view illustrating a schematic diagram of a high-speed resistance measurement system according to the present invention;

Fig. 7 is a view illustrating a resistance measurement conceptual diagram for the high-speed resistance measurement system according to the present invention;

Fig. 8 is a view illustrating a resistance measurement circuit diagram for the high-speed resistance measurement system according to the present invention;

Figs. 9a~9c are resistance measurement conceptual diagrams for the high-speed resistance measurement system according to the present invention; Fig. 10 is a block diagram of a DSP (Digital Signal Processing) board included in the high-speed resistance measurement system according to the present invention;

Fig. 11 is a view showing the configuration of a switching controller included in a main resistance measurement unit according to the present invention; Fig. 12 is a view showing the configuration of a switching section included in the main and extended resistance measurement units according to the present invention;

Fig. 13 is a view illustrating a first example of a resistance measurement using the high-speed resistance measurement system according to the present invention;

Fig. 14 is a view illustrating a second example of a resistance measurement using the high-speed resistance measurement system according to the present invention;

Fig. 15 is a flow chart illustrating an open/short inspection process using the high-speed resistance measurement system; and

Fig. 16 is a flow chart illustrating a resistor- trimming process using the high-speed resistance measurement system.

Best Mode for Carrying Out the Invention

Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.

Fig. 6 is a view schematically showing the configuration of a high-speed resistance measurement system according to the present invention. Referring to this drawing, main elements of the system will hereinafter be described in detail.

A host computer 100 includes a DSP (Digital Signal Processing) board 200. The DSP board 200 transmits a control signal to a main resistance measurement unit 300 according to an entry control instruction, and enables the results from the main resistance measurement unit 300 to be displayed on the host computer 100. The DSP board 200 includes an application program for determining trimming states or open/short states of a plurality of resistors on the basis of the results from the main resistance measurement unit 300. The host computer 100 loads the application program from the DSP board 200, and receives a variety of control instructions regarding an inspection mode, a measurement mode, measurement condition factors, etc., using the application program. After processing the measured resistance according to the control instruction, the DSP board 200 allows the trimming states or open/short states of the resistors to be collectively or sequentially outputted or stored through the application program, whereby an inspector can easily confirm the result data while manipulating the host computer 100 on which the application program is displayed.

The control instructions entered by the inspector include a variety of instructions regarding an inspection mode, a measurement mode, a measurement condition factor, etc. The inspection mode is classified into an open inspection mode of PDP glass electrodes, a short inspection mode of PDP glass electrodes, and a resistor-trimming process mode. According to an inspection mode selected by the inspector, the control instructions may contain a variety of information, for example, a reference value for determining an electrode open-state, a reference value for determining an electrode short-state, an allowable range of a trimming resistance on the basis of a target resistance, and a prescribed factor for determining whether a trimming resistor is good or poor. Such information is determined and entered by the inspector.

The measurement mode is classified into a single resistance measurement mode where two terminals are brought into contact with two ends of a resistor, respectively, and a delta resistance measurement mode where a guard terminal and the two terminals are brought into contact with three resistance ends, respectively.

The measurement condition factor includes a resistance range setup factor, a sequentially-switched channel, the number of resistors to be measured, and the number of times the measurement is repeated, etc. The measurement condition factor further includes a target resistance, a trimming stop condition, etc. needed in a resistor-trimming process, and therefore, they are determined and entered by the inspector in the resistor-trimming process.

By establishing data transmission and reception with the host computer 100, the DSP board 200 built in the host computer 100 receives a control instruction containing a plurality of measurement conditions for resistance measurement, and controls a switching controller 320 and a switching section 330 contained in the main resistance measurement unit 300, in such a way that resistance measurement is performed. The DSP board 200 transfers the measured results in real time or collectively to the host computer 100. During this procedure, the DSP board 200 utilizes its own memory to rapidly perform a signal processing for resistance measurement, such that individual resistances of a plurality of resistors are collectively measured and data congestion that may occur when collectively transferring the measured results is controlled. The main resistance measurement unit 300 is controlled by the DSP board

200, and connected to an extended resistance measurement unit 400 for measuring additional resistances. The main resistance measurement unit 300 includes a power-supply unit 310, the switching section 330, and the switching controller 320. The power-supply unit 310 provides a power-supply signal for resistance measurement to a plurality of relays according to a control signal received from the DSP board 200. The switching section 330 switches on/off the relays receiving the power-supply signal from the power supply unit 310, and thus provides resistance measurement. The switching controller 320 controls the switching section 330 to switch on/off the relays according to the control signal or prescribed setup values. As the relays are switched on, the main resistance measurement unit 300 outputs the measured resistances to the DSP board 200.

In the case where there are many resistors to be measured, the extended resistance measurement unit 400 having an extended switching section 430 connected to resistors is also needed in addition to the main resistance measurement unit 300. The extended resistance measurement unit 400 is controlled by the power-supply unit 310 and the switching controller 320 of the main resistance measurement unit 300.

The switching section 330 and the extended switching section 430 perform a resistance measurement by extendedly connecting their cables to a plurality of probes 420 in contact with a plurality of resistors or PDP glass electrodes to be - measured.

For measurement of various types of resistors, the high-speed resistance measurement system according to the present invention may employ a four- terminal measurement method shown in Fig. 7, such that an accurate resistance measurement can be performed even when two ends of a resistor are long in length. The four-terminal measurement method (a Kelvin measurement method) can precisely measure an instantaneously low resistance by connecting two terminals to each of the two ends. Irrespective of the length (denoted by a dotted line in Fig. 7) between both ends of a resistor R, the four-terminal measurement method can perform an accurate resistance measurement and can be applicable to various types of resistors.

In the four-terminal measurement method, four measurement terminals F+ (i.e., force plus), S+ (i.e., sense plus), F-, and S- are connected to both ends of a general single resistor, in such a manner that terminals F+ and S+ are connected to one end of the resistor, and terminals F- and S- are connected to the other end of the resistor. In the case of a delta resistor, guard force and guard sense terminals are added to the four terminals. The guard force terminal is adapted to supply power to a resistor to be measured, and the guard sense terminal is adapted to sense a measured resistance.

Fig. 8 is a view showing a circuit for measuring a delta resistor using the high-speed resistance measurement system according to the present invention. Figs. 9a, 9b, and 9c are views showing steps of measuring the delta resistor according to the switching sequence.

In the case of measuring a resistance of a single resistor, a plurality of relays SW1 to SW6 provides the resistor to be measured with power over the force plus and minus terminals F+ and F- connected to both ends of the resistor. The relays SW1 to SW6 are connected to the sense plus terminal S+ connected to one end of the resistor to which the force plus terminal F+ is connected, and are connected to the sense minus terminal S- connected to the other end of the resistor to which the force minus terminal F- is connected, in such a way that a resistance of the resistor is measured.

On the other hand, in the case of measuring the resistance of a delta resistor as shown in Fig. 8, the guard force terminal and the guard sense terminal are connected to an end of the delta resistor to which the force and sense plus terminals F+ and S+ and the force and sense minus terminals F- and S- are not connected. In this case, the plurality of relays SW1 to SW6 are switched on/off, so that the force and sense plus terminals F+ and S+, the force and sense minus terminals F- and S-, and the guard force and guard sense terminals are sequentially connected to a corresponding resistor end of the delta resistor, thereby obtaining measured values XI, X2, and X3. The measured results are subject to a calculation process in the DSP board 200 to obtain resistances of resistors Rl, R2, and R3. [Table 1]

SWl SW2 SW3 SW4 SW5 SW6 Relationship Measured (F+) (F-) (Guard) (S+) (S-) (Guard between Resistance Equation

Sense) resistors

1st Switch Switch Switch Switch Ril l switching to to Off to to Off (R2+R3) XI Eq.Φ side-1 side-2 side-1 side-2

2^nJ Switch Switch Switch Switch switching to to On to to On Rl| I R2 X2 Eq.C side-1 side-2 side-1 side-2

3^rd Switch Switch Switch Switch switching to to On to to On Rl| I R3 X3 Eq.C side-2 side-I side-2 side-1

Referring to Table 1, when the switches SWl to SW6 in the circuit of Fig. 8 are switched to a first switching state, the circuit may be simplified as shown in Fig. 9a. In this case, a resistance relationship of Rl j J (R2+R3) is satisfied, so the switching section 330 measures a resistance XI as represented by the following equation φ, and the measured result is transferred to the switching controller 320.

__ .. ^ _V1 {R1 XR2) + {R1 XR3)

Equation (1) : X = - — -

⁴ {RI + R2 + R3)

Subsequently, when the switches SWl to SW6 in the circuit of Fig. 8 are switched to a second switching state, the circuit may be simplified as shown in Fig. 9b. In this case, the resistor R3 (denoted by a dotted line) and a non-resistance line (denoted by a solid line) are parallel to each other, so that the resistor R3 is disregarded, resulting in a resistance relationship of Rl | j R2. Therefore, the switching section 330 measures a resistance X2 as represented by the following equation (D, and the measured result is transferred to the switching controller 320.

R1 XR2

Equation X2 -- R1 + R2 Finally, when the switches SWl to SW6 in the circuit of Fig. 8 are switched to a third switching state, the circuit may be simplified as shown in Fig. 9c. In this case, the resistor R2 (denoted by a dotted line) and a non-resistance line (denoted by a solid line) are parallel to each other, so that the resistor R2 is disregarded, resulting in a resistance relationship of Rl j | R3. Therefore, the switching section 330 measures a resistance X3 as represented by the following equation d), and the measured result is transferred to the switching controller 320.

Equation (3) : X3 = ^{R1X R3}

RI +R3

The switching controller 320 transfers the measured values XI, X2, and X3 from the switching section 330 to the DSP board 200. Based on the values XI, X2, and X3, the DSP board 200 obtains resistance values of the resistors Rl, R2, and R3. Firstly, a resistance of the resistor Rl is obtained based on the following equation @, and the remaining resistances of the resistors R2 and R3 are obtained based on the resistance value of the resistor Rl, in such a way that resistances Rl, R2, and R3 of delta resistors can be measured.

(Z2 -Z3± 2² - 3² - 1 - Z2 - Z3 - (X2 + X3 -Z1)

Equation ©: Rl =

Jπ + X2 + X3

Fig. 10 is a view showing the configuration of the DSP board 200 contained in the high-speed resistance measurement system according to the present invention. The DSP board 200 sends data measured by the main resistance measurement unit 300 and the extended resistance measurement unit 400 to the host computer at a high transfer rate without data congestion, thereby making it possible to collectively measure a plurality of resistances.

The DSP board 200 receives control instructions entered by the inspector, for example, instructions for controlling an inspection mode, a measurement mode, measurement condition factors, etc., from the host computer 100 over an ISA bus 210, sends the received control instructions to a dual buffer 220, and transmits its own signal processing result to the host computer 100.

1

The dual buffer 220 serves as an intermediate buffer used for data transmission and reception between the host computer 100 and a DSP processor 230. A memory unit 240 includes a DRAM 241 and a boot EEPROM 242. The DRAM 241 stores control instructions received from the host computer 100, measured resistances received from the switching controller 320, and results calculated by a DSP processor 230. The boot EEPROM 242 stores a boot program that initially operates at the same time when power is supplied to the DSP board 200.

The DSP processor 230 is a processor composed of a timer, a counter, and a RAM. The DSP processor 230 outputs a control signal to the main resistance measurement unit 300 so as to measure a resistance according to the control instruction received at the host computer 100, performs a calculation process on the measured resistance according to the control signal, and finally transfers the resultant resistance to the host computer 100.

A set value output unit 260 includes a power range output section 261, a channel output section 262, and a target value output section 263. The power range output section 261 sets an internal power range of the switching controller 320 on the basis of a resistance to be measured, and outputs the set power range value to the switching controller 320. The channel output section 262 sets a channel number for determining a measurement sequence of the resistors, and outputs the set channel number to the switching section 330. The target value output section 263 outputs a target resistance to the switching controller 320 during a resistor trimming process.

An ADC (Analog-to-Digital Conversion) controller 270 converts digital data outputted from the set value output unit 260 into analog data, and outputs a conversion signal to the main resistance measurement unit 300, so that measurement results to be transferred from the main resistance measurement unit 300 are converted into digital data.

A parallel input/output buffer 250 sends a control signal received from the DSP processor 230 to the main resistance measurement unit 300 over the set value output unit 260, and performs an intermediate buffering to transfer resistance data measured by the main measurement unit 300 to the DSP processor 230.

Fig. 11 is a view showing the configuration of the switching controller 320 included in the main resistance measurement unit 300 according to the present invention. The main resistance measurement unit 300 will now be described in detail referring to this drawing. The power range varies depending on the resistors to be measured. According to a power range set value outputted from the power range output section 261 of the DSP board 200, a power range selection section 321 selects a power range and generates a power source. Each power range is determined according to a control instruction entered by an inspector on the host computer 100. If one power range is set, there is no need to additionally set a power range for a different resistor of the same range as the set range. In order to reduce power consumption and increase measurement sensitivity, switches connected to respective resistors are simultaneously switched on/off for supplying power.

A terminal selection section 322 is turned on by a control signal outputted from the DSP board 200 during a resistance measurement, in which an on/off switching is performed because a terminal F+ is interoperable with a terminal S+, a terminal F- is interoperable with a terminal S-, and a guard force terminal is interoperable with a guard sense terminal. The guard force and guard sense switches are additionally used only for measuring a delta resistor, and a general resistor, other than the delta resistor, is measured by bringing four terminals F+, S+, F-, and S- into contact with both ends of the resistor. All the switches are turned off when no measurement is performed.

When the force and sense terminals are brought into contact with a resistor to be measured after power is applied to the resistor, an A/D converter 323 converts a measured analog resistance value into digital data according to a control signal outputted from the ADC controller 270 of the DSP board 200, and then transfers the digital data to the DSP board 200.

A sense pre-processor 324 obtains a potential difference among analog signals outputted from the terminals S+ and S-, and the guard sense terminal, such that an accurate resistance measurement can be established.

A target resistance of a resistor to be trimmed, which is received from the host computer 100, is transferred to the DSP board 200, and then transferred to a target value setting section 325 of the switching controller 320. The target value setting section 325 converts the digital type of target resistance into an analog signal, and then outputs it to a comparator 326.

The comparator 326 compares the analog type of target resistance with the analog type of measured resistance outputted from the sense pre-processor 324. If the measured resistance is higher than the target resistance, the comparator 326 outputs an impulse signal, which rises from a low level to a high level, to the DSP board 200, such that a laser device for trimming the resistor stops operating. The laser device (not shown) trims a film of a resistor by emitting a laser beam to the resistor in such a way that the resistor reaches the target resistance.

The resistance of the trimmed resistor is measured in real time simultaneously with performing the trimming process, such that the laser beam is continuously emitted until the measured resistance is identical with the target resistance.

Upon receiving an impulse signal from the comparator 326, the DSP board 200 connected to the laser device outputs a stop signal for stopping the laser device's operation to the laser device in such a way that a trimming process is completed. In addition, the DSP board 200 calculates an error between the resistance of the trimmed resistor and the target resistance, and transfers the error to the host computer, such that the host computer outputs or stores it.

Fig. 12 is a view showing the configuration of the switching section included in the main resistance measurement unit according to the present invention. The switching section will now be described in detail with reference to Fig. 12.

The main resistance measurement unit 300 further includes a plurality of switching sections 330 and switching section selectors (not shown) for selecting a specific switching section to be controlled from among the plurality of switching sections.

The extended resistance measurement unit 400 is a resistance measurement unit, which is connected to the main resistance measurement unit 300 when the number of resistors to be measured exceeds the maximum allowable number of resistors of the main resistance measurement unit 300. The extended resistance measurement unit 400 includes a plurality of extended switching sections 430. The extended switching sections 430 perform a resistance measurement by switching on/off relays according to a control signal outputted from the switching controller 320, and transfer measured resistances to the main resistance measurement unit 300. The extended switching sections 430 have the same configuration as the switching sections included in the main resistance measurement unit 300.

1

A control signal from the DSP board 200 is transmitted to the switching section 330 through the switching controller 320. The switching section 330 selects a channel to be connected to a measurement target resistor according to the control signal, supplies power to the selected channel, and is then connected to a terminal to be brought into contact with the resistor.

A channel selection buffer 331 buffers a channel number, set in the channel output section 262 of the DSP board 200, in an IC (Integrated Chip) for controlling a switching operation of a channel having the channel number. The term "channel" means an end of a resistor, so both ends of a single resistor each correspond to one channel.

An IC (denoted by "IC1" in Fig. 12) controls a switching operation of six relays for measuring a resistance of a resistor connected to a first channel, and each IC outputs a switching control signal to the six relays connected to 6 terminals (i.e., four terminals F+, F-, S+, and S-, a guard force terminal, and a guard sense terminal).

An IC selector 332 selects an IC, connected to a measurement target resistor, from among a plurality of ICs according to a control signal of the DSP board 200, and generates enable/disable signals for activating a relay switching function implemented in the IC.

A relay drive section 334 outputs a drive signal to a relay connected to a terminal to be brought into contact with a measurement target resistor so that the relays perform a switching operation according to a relay switching function implemented in an IC selected by the IC selector 332. The relay driving section 334 includes a plurality of ICs implemented for performing a switching operation of relays connected to six terminals which can be in contact with the resistor.

As a plurality of relays having a high speed switching function, connected to 6 terminals (force plus and minus terminals F+ and F-, sense plus and minus terminals S+ and S-, a guard force terminal, and a guard sense terminal), are switched on/off according to a drive signal generated from the relay drive section 334, one end of a single resistor or a Y-shaped resistor is brought into contact with force and sense plus terminals through a first pin probe PP1, and the other end is brought into contact with force and sense minus terminals F- and S- through a second pin probe PP2. In the case where a resistance of a delta resistor is measured, force and sense plus terminals F+ and S+, force and sense minus terminals F- and S-, and guard force and sense terminals are connected to respective ends of the delta resistor.

Fig. 13 is a view illustrating a first example of a resistance measurement R2002/002288

using the high-speed resistance measurement system according to the present invention. In this drawing, dotted-line resistors denote probes that can be brought into contact with a delta resistor when the delta resistor is measured.

It can be seen from this drawing that a first pin (or pin 1), a. second pin (or pin 2), a third pin (or pin 3), and a fourth pin (or pin 4) are connected to terminals F+, S+, F-, and S-, respectively, according to the switching operation of relays when a single resistor is measured. A left end of the single resistor is connected to the terminals F+ and S+, combined with each other, and a right end thereof is connected to terminals F- and S-, combined with each other. In Fig. 13, solid-line arrows denote pin probes PP1 to PP4 for connecting the resistor with the plurality of pins in the high-speed resistance measurement system according to the present invention.

When a delta resistance measurement is performed with a triangular connection of resistors Rl, R2, R3, the resistor Rl is measured by a four-terminal measurement method as follows. In more detail, one end of the resistor Rl is connected to two terminals (Pin 1 and Pin 2) because 6 terminals (F+, F-, S+, S-, and guard force and sense terminals) forming one channel are switched on, and the other end of the resistor Rl is connected to two terminals (Pin 3 and Pin 4) because 6 terminals (F+, F-, S+, S-, and guard force and sense terminals) forming another channel are switched on.

Similarly to the resistor Rl, the resistors R2 and R3 are measured by the four-terminal measurement method, in such a manner that both ends of the resistors R2 and R3 are each connected to two respective terminals, as 6 relays contained in a corresponding channel are switched on. As shown in Fig. 13, the resistors R2 and R3 are connected to the guard force terminal through a pin probe PP5 in contact with a fifth pin (Pin 5), and are connected to the guard sense terminal through a pin probe PP6 in contact with a sixth pin (Pin 6).

Fig. 14 is a view illustrating a second example of a resistance measurement using the high-speed resistance measurement system according to the present invention.

In the case where, in a PDP manufacturing process, an open/short inspection of a plurality of electrodes is performed by the high-speed resistance measurement system according to the present invention, the plurality of electrodes can be regarded as a plurality of single resistors continuously disposed on the condition that one PDP electrode is regarded as one resistor (R). Thus, after simultaneously bringing the probes of the high-speed measurement system into contact with both ends of a resistor (an electrode), a plurality of resistors are rapidly measured by successively switching on/off a plurality of relays of the switching sections which perform a high speed switching operation. The measured results are outputted to the host computer, thereby allowing an inspector to collectively check the measured results.

One end of a resistor corresponds to one channel, and when two pin probes are brought into contact with an end of a resistor, a force terminal or a sense terminal is connected thereto. Therefore, the number of channels assigned for measurement of M single resistors is 2M, and the total number of pin probes PP1 to PPN is 4M.

Information regarding a channel prescribed in the DSP board 200 is transferred to the switching section 330 of the main resistance measurement unit 300 through the channel output section 262, and thereby the relay drive section 334 allows the plurality of relays to be switched on/off for resistance measurement. The following Table 2 shows the number of channels connected to terminals F+ and F- for measuring resistances of M resistors (electrodes).

[Table 2]

Order of Measurement F+ F-

lst resistor Channel 1 Channel 2 2nd resistor Channel 3 Channel 4

3rd resistor Channel 5 Channel 6

4th resistor Channel 7 Channel 8

M-th resistor Channel 2M-1 Channel 2M As shown in the above Table 2, the relay drive section 334 switches the relays to connect force plus and minus terminals F+ and F- with individual channels, the sense plus terminal S+ is interoperable with the force plus terminal F+, the sense minus terminal S- is interoperable with the force minus terminal F-, such that the sense terminals are automatically set up at the same time according to setup information of the force terminals. The Table 2 depicts a channel setup process wherein 2M channels are set up for M resistors for the convenience of description and better understanding of the present invention. However, provided much more resistors are adapted to such a channel setup process, the extended resistance measurement unit 400 may be additionally adapted to set up much more channels, in such a way that a plurality of resistances can be measured.

Operations of a high-speed resistance measurement system are as follows.

In the same manner as those of the conventional art shown in Figs. 1~5, a manual resistance meter and a resistance measurement method using the same will hereinafter be described with reference to Figs. 15~16, wherein a process for manufacturing channels of a PDP is adapted as a first preferred embodiment of the present invention and a resistor trimming process is adapted as a second preferred embodiment of the present invention.

Fig. 15 is a flow chart illustrating an open/short inspection process using the high-speed resistance measurement system. The first preferred embodiment will hereinafter be described with reference to Fig. 15. The inspector sets up the number of measurement target resistors and channels depending on the order of resistance measurement on an application program displayed on the host computer. The inspector enters a control command having a variety of initial setup data, for example, instructions regarding an inspection mode, a measurement mode, measurement condition factors, etc., using the application program. In this case, the measurement condition factors contain a reference value for determining an open state and a reference value for determining a short state, etc. The control command is transferred to the DSP board at step SI.

A sample to be measured is loaded at step S2, and probes are in contact with both ends of each PDP electrode at step S3. The DSP board loads the initial setup data stored in the DRAM at step S4, and power source in a power range of a target resistor is supplied at step S5.

A high-speed switching operation is performed according to the channels and the order of target resistors to measure resistances of the target resistors, and the measured resistances are stored in the dual buffer at step S6.

The host computer loads and reads resistances stored in the dual buffer of the DSP board. The host computer determines whether many electrodes are shorted or open on the basis of the prescribed open/short reference values, and then either displays the results of determination on its own screen or stores them in a file format at step S8.

The above operations are repeated in proportion to the number of measurement target resistors to be checked. If such operations are completed, the sample is unloaded and the open/short inspection for electrodes is also terminated.

Fig. 16 is a flow chart illustrating a resistor-trimming process using the high-speed resistance measurement system. The second preferred embodiment will hereinafter be described with reference to Fig. 16.

The inspector sets up the number of measurement target resistors and channels depending on the order of resistance measurement on an application program displayed on the host computer. The inspector enters a control command having a variety of initial setup data, for example, instructions regarding an inspection mode, a measurement mode, measurement condition factors, etc., using the application program. In this case, the measurement condition factors contain a target resistance for a resistor-trimming process. The control command is transferred to the DSP board at step Ll.

The application program corrects the target resistance on the basis of a measurement error variable with heat emitted from laser beam in a trimming process using a laser device, resulting in more precise resistance trimming.

The resistor type is set to either one of a general single resistor, Y-shaped resistor, and a delta resistor. The delta resistor additionally uses a guard pin, and connects it to the resistor.

A resistor sample to be trimmed is loaded at step L2, and probes are brought into contact with the resistor sample at step L3.

The DSP board loads the initial setup data from the host computer at step L4, and allows power to be supplied according to a power range setup value of the trimming resistor at step L5.

The laser beam is emitted from the laser device to perform a trimming process at step L6, and a resistance measurement is performed according to a channel selection result of the trimming resistor at step L7. It is determined whether the measured resistance is identical with the target resistance at step L8. As soon as the measured resistance is identical with the target resistance at step L8, a stop signal for powering off the laser device is generated at step L9, such that the laser device stops operating upon receiving the stop signal. After the trimming process is completed, a resistance of the trimmed resistor is stored in a dual buffer of the DSP board. The host computer reads out the resistance of the trimmed resistor from the DSP board, calculates a difference (i.e., error) between the read resistance and the target resistance according to a prescribed calculation process contained in the application program at step E10, and displays it on a screen of the host computer or stores it in a file format at step Lll.

The above operations are repeated in proportion to the number of resistors to be trimmed. If such operations are completed, the sample is unloaded and the resistor-trimming process is also terminated.

Industrial Applicability

As apparent from the above description, the present invention provides a high-speed resistance measurement system, which automatically performs open/short inspections on a plurality of resistors to reduce the required manpower and a total inspection time in the PDP manufacturing lines, accurately selects a defective resistor from among many resistors to enhance the quality of electronic applications having normal resistors, and performs a resistor-trimming process with a target resistance to automatically and precisely measure respective resistances of various kinds of resistors, for example, a single resistor, a Y-shaped resistor, and a delta resistor, etc., resulting in an accurate trimming process at high speed, the improvement of productivity, and greater convenience for a user such as an inspector who handles an inspection mode and a resistor trimming process.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

02 002288Claims:

1. A high-speed resistance measurement system, comprising: a host computer for receiving an entry control command adapted to automatically perform an open/short inspection or a trimming process, and outputting result data according to the control command; and a main resistance measurement unit for automatically performing the open/short inspection or the trimming process on the plurality of resistors according to the control command received at the host computer, and transmitting result data to the host computer.

2. The system as set forth in claim 1, wherein the host computer includes a DSP (Digital Signal Processing) board for transmitting a control signal to the main resistance measurement unit according to the entry control command, and enabling result data transmitted from the main resistance measurement unit to be displayed on the host computer.

3. The system as set forth in claim 2, wherein the DSP board contains an application program for determining an open/short state or a trimming state of the resistors upon receiving the result data from the main resistance measurement unit, and wherein the host computer outputs or stores the open/short state or the trimming state of the resistors when the application program is driven.

4. The system as set forth in claim 2, wherein the main resistance measurement unit switches on/off a plurality of relays for selectively providing a plurality of terminals in contact with the plurality of resistors with power according to a control signal generated from the DSP board; and wherein the DSP board receives a resistance measured by a switching operation of the plurality of relays.

5. The system as set forth in claim 4, wherein the plurality of relays are connected to force plus and minus terminals connected to both ends of a resistor to be measured in order to provide the resistor with power, are connected to a sense plus terminal connected to a resistor end to which the force plus terminal is T KR2002/002288

connected in order to measure a resistance of the resistor upon receiving the power from the force plus and minus terminals, and are also connected to a sense minus terminal connected to a resistor end to which the force minus terminal is connected.

6. The system as set forth in claim 5, wherein the plurality of relays, in case of measuring a delta resistor, are connected to guard force and sense terminals connected to a resistor end to which the force plus and minus terminals and the sense plus and minus terminals are not connected, wherein the force plus terminal and the sense plus terminal, the force minus terminal and the sense minus terminal, and the guard force terminal and the guard sense terminal are sequentially connected to individual resistor ends of the delta resistor, and switched.

7. The system as set forth in claim 4, wherein the DSP board includes: a DSP processor for outputting a control signal used for measuring a resistance according to a control command received at the host computer to the main resistance measurement unit, and at the same time performing a calculation process on a measured resistance detected by the control signal; a memory for storing the control command, the measured resistance transmitted from the main resistance measurement unit, and result data transmitted from the DSP processor; a set value output unit for determining a power range proper to resistors to be measured, a channel number determining a measurement order of the resistors, or a target resistance in a trimming process of the resistors, and transmitting the power range, the channel number, and the target resistance to the main resistance measurement unit; and an ADC (Analog-to-Digital Conversion) controller for converting digital data outputted from the set value output unit into analog data, and at the same time outputting a conversion signal to the main resistance measurement unit, whereby result data to be transferred from the main resistance measurement unit are converted into digital data.

8. The system as set forth in claim 7, wherein the DSP board further includes: a dual buffer for performing an intermediate buffering for data transmission and reception between the host computer and the DSP processor; and a parallel input/output buffer for sending a control signal received from the DSP processor to the main resistance measurement unit over the set value output unit, and performing an intermediate buffering to transfer resistance data measured by the main resistance measurement unit to the DSP processor.

9. The system as set forth in claim 7, wherein the main resistance measurement unit includes: a power-supply unit for providing a power-supply signal for resistance measurement to the relays according to a setup value from the set value output unit or a control signal received from the DSP board; a switching unit for switching on/off the relays receiving the power- supply signal from the power-supply unit so as to perform a resistance measurement; and a switching controller for controlling the switching unit to switch on/off the relays according to either the setup value or the control signal.

10. The system as set forth in claim 9, wherein the switching controller includes: a power range selector for selecting a power range of a power-supply signal supplied to the relays over the power-supply unit according to the setup value; a terminal selector for selecting a force terminal or a sense terminal to be electrically in contact with a target resistor according to the control signal, and switching on/off the relays; and an AD (Analog-to-Digital) converter for converting the target resistance transmitted from the set value output unit into analog data while a trimming process is performed according to the conversion signal of the ADC controller, at the same time converting an analog resistance measured by the switching unit into digital data, and transmitting the digital data to the DSP board.

11. The system as set forth in claim 10, further comprising: a laser device for emitting a laser beam to a resistor to be trimmed in a resistor trimming process until the resistor reaches a target resistance, wherein the DSP board connected to the laser device generates a stop signal for stopping an operation of the laser device when a resistance measured in real time is identical with the target resistance in the trimming process, and calculates an error between a resistance of the trimmed resistor and the target resistance after the trimming process is completed, and controls the host computer to output or store it.

12. The system as set forth in claim 11, wherein the comparator compares the analog target resistance converted by the AD converter with a resistance measured by the switching unit in the trimming process to determine whether the measured resistance is identical with the target resistance, and transmits a control signal indicating that the measured resistance is identical with the target resistance to the DSP board.

13. The system as set forth in claim 9, wherein the main resistance measurement unit further includes: a plurality of switching units; and a switching unit selector for selecting a switching unit to be used for controlling a switching operation of the relays from among the plurality of switching units.

14. The system • as set forth in claim 13, wherein the switching unit includes: a channel selection buffer for buffering a channel number, set in the set value output unit, in an IC (Integrated Chip) for controlling a switching operation of a channel having the channel number; an IC selector for outputting an enable signal or a disable signal to the IC to perform a relay switching function implemented in the IC; a relay drive for outputting a driving signal to a relay connected to a terminal to be brought into contact with a target resistor so that the relay performs a switching operation according to the relay switching function implemented in the IC selected by the IC selector; and a plurality of relays being switched on/off at high speed upon receiving the driving signal from the relay drive.

15. The system as set forth in claim 14, further comprising: an extended resistance measurement unit being connected to the main resistance measurement unit when the number of resistors to be measured exceeds maximum allowable number of resistors of the main resistance measurement unit, wherein the extended resistance measurement unit performs a resistance measurement by switching on/off the relays according to a control signal generated from the switching controller, and transfers measured resistances to the main resistance measurement unit.