JP2007156127A - Method for inspecting electro-optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting an electro-optical apparatus, where display defects in a special drive state that is different from a normal driving state can be also detected. <P>SOLUTION: In the method for inspecting the electro-optical apparatus provided with a plurality of scanning lines 31 for supplying scanning signals, a plurality of data lines 35 for supplying pixel signals, obtained by sampling an image signal to respective pixels and a plurality of switching elements 30, formed so as to correspond to intersections between the scanning lines and the data lines; scanning signals are supplied from the scanning lines 31 to all the gates of the switching elements 30, to simultaneously turn on both the ends of all the switching elements 30, and pixel signals for inverting polarity are applied from the data lines, to one-ends of the switching elements in each prescribed period that is smaller than one vertical scanning period to turn on all pixels. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inspection method for an electro-optical device for detecting a defective pixel having a high resistance when a switching element is turned on, among pixel defects of an electro-optical panel such as a liquid crystal panel.

  In general, an electro-optical panel, for example, a liquid crystal panel, includes a pair of substrates that sandwich an electro-optical material liquid crystal, a pair of electrodes that drive the liquid crystal, a plurality of scanning lines that supply a scanning signal, and a pixel that samples an image signal. A plurality of data lines for supplying signals to the pixels, and a plurality of switching elements provided corresponding to the intersections of the scanning lines and the data lines.

  In the liquid crystal panel manufacturing process, display defects (point defects, surface defects) caused by defective switching elements such as thin film transistors (hereinafter referred to as “TFTs”) and foreign matters mixed into the liquid crystal layer , Scratches, dust, etc.) are inspected (for example, see Patent Documents 1 to 3).

When performing such an inspection, a driving signal is supplied to the liquid crystal panel to display a specific pattern for inspection, and the inspection is performed.
JP-A-8-233888 JP 2004-101941 A JP 2004-101943 A

  By the way, in driving a liquid crystal panel using TFT as a switching element, the voltage written to each pixel is (1) pixel gate on (write start), (2) source write, and (3) source voltage hold. The cycle of writing to the pixel, (4) turning off the pixel gate (ending writing), and (5) holding the pixel voltage is repeated. Here, in a normal driving state of the liquid crystal panel, even if the resistance between the source and drain of the pixel is high, if the pixel voltage is written to a predetermined voltage during the period up to (3), pixels for one screen (frame) Since the voltage written to each pixel is maintained until the writing is completed, no display defect occurs.

  However, when the pixel voltage is inverted (using a signal whose polarity is inverted at a constant period), when the frequency of the inversion is changed to a higher value, a display defect occurs due to insufficient writing to the pixel. For example, when the writing is insufficient when the liquid crystal panel is normally white, a white bright spot is displayed on the screen where the pixel voltage should be black. In other words, the inspection in the normal driving state does not cause a display defect, but there is a problem that it may be visually recognized as a display defect when a driving state such as a driving frequency is changed.

  In view of the above problems, an object of the present invention is to provide an inspection method for an electro-optical device capable of detecting a display defect that appears in a special driving state different from a normal driving state. is there.

  An inspection method for an electro-optical device according to the present invention corresponds to a plurality of scanning lines for supplying scanning signals, a plurality of data lines for supplying pixel signals obtained by sampling image signals to the pixels, and intersections of the scanning lines and the data lines. An inspection method for an electro-optical device including a plurality of switching elements provided, wherein a scanning signal is applied from the scanning line to all gates of the switching elements to simultaneously turn on both ends of the switching elements, and A pixel signal whose polarity is inverted every predetermined period smaller than one vertical scanning period is supplied from the data line to one end of the switching element to turn on all the pixels.

According to such a method of the present invention, all the scanning lines are simultaneously turned on, and the polarity of the data lines is inverted every predetermined period (for example, one horizontal scanning line period) smaller than one vertical scanning period (one frame or one field). By supplying pixel signals, all pixels are lit (referred to as “all pixels on”) (here, black display or halftone display is used when lit in normally white mode), and each pixel has a relatively short period. Since a signal whose polarity is inverted is written to the pixel, even if the switching element (for example, TFT) is always on, the signal is sufficiently written in a pixel having a normal (proper) resistance value at both ends (between the source and drain). However, the pixel voltage is insufficiently written in a pixel (defective pixel) having a high resistance value between the source and the drain, so that the pixel becomes a bright spot. Thereby, since it is observed as a bright spot, a defective pixel can be easily detected.
In the present invention, the pixel signal is a signal of the same level in all data lines.

According to such a method, pixel signals having the same level are given to all the pixels, and the luminance is obtained under the same conditions, can be detected as a defective pixel.
In the present invention, the signal level of the pixel signal is a halftone level.
According to such a method, when the electro-optical device is, for example, a liquid crystal device, there is a difference of 0.5 V between the writing effective voltage of, for example, 5.0 V and 4.5 V due to the characteristics of the liquid crystal panel. In any state in which the pixels are lit (on), the difference is almost unknown in the black display. Therefore, at the time of lighting inspection, it is easy to distinguish the defect quality (difference) by lighting all the pixels with a signal of a halftone level that is intermediate between black and white rather than determining that all the pixels are black.

The present invention is characterized in that the polarity inversion period can be made variable to detect a difference in the degree of display defects.
According to such a method, when a signal whose polarity is inverted every predetermined period is written to the pixel, when the resistance value between the source and the drain is different by performing driving with the period of the write voltage variable, for example, If the polarity reversal period is shortened, the pixel voltage is insufficiently written only when the resistance value is slightly higher than the normal value, and detection as a bright spot (defective pixel) becomes possible.

In the present invention, the polarity inversion is performed at least every predetermined number of horizontal scanning periods of 1 or more.
According to such a method, the quality of the pixel is determined by whether or not the voltage written to the pixel is sufficiently large during a period that is an integral multiple of the period during which one row is written (for example, one horizontal scanning period).

  In the present invention, the polarity inversion is performed in units of pixels in addition to inversion every predetermined number of horizontal scanning periods of at least one or more.

  According to such a method, since the inversion period is in units of pixels, the quality of the pixels can be determined based on the magnitude of the voltage written to the pixels during the minimum period.

Embodiments of the invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a configuration of an active matrix substrate in a liquid crystal device to which an inspection method for an electro-optical device according to a first embodiment of the present invention is applied.
In FIG. 1, a TFT substrate 1 as an active matrix substrate is made of, for example, a quartz substrate, hard glass, a silicon substrate, or the like. On the TFT substrate 1, a plurality of pixel electrodes 11 provided in a matrix, a plurality of data electrodes 35 arranged in the X direction and extending in the Y direction, and a plurality of data electrodes 35 arranged in the Y direction are arranged. Are respectively provided between the scanning line 31 extending along the X direction, each data line 35 and the pixel electrode 11, and a conduction state and a non-conduction state between them are respectively supplied via the scanning line 31. A plurality of TFTs 30 are formed as switching elements to be controlled in response to the signals Y1, Y2,. On the TFT substrate 1, a capacitor line 31 ′ that is a wiring for the storage capacitor 70 is formed substantially in parallel along the scanning line 31 so that the storage capacitor 70 is added to the pixel electrode 11. To do. Thus, by holding the pixel voltage in the storage capacitor 70, it is possible to prevent display quality deterioration such as flicker caused by leakage from the storage capacitor. In order to form the storage capacitor 70, the preceding scanning line 31 may be used as an electrode for forming the storage capacitor. By adopting such a configuration, it is not necessary to provide the capacitor line 31 ′, so that the pixel aperture ratio can be improved and a bright liquid crystal device can be provided. Pixel data S1, S2,..., Sn obtained by sampling in a sampling circuit 301 described later are supplied to the data line 35 and written therein. The pixel signals S1, S2,..., Sn written to the data line 35 may be supplied sequentially in this order, or may be supplied to a plurality of data lines 35 simultaneously.

Further, on the TFT substrate 1, a precharge signal NRS having a predetermined voltage level is supplied to the plurality of data lines 35 prior to the pixel signals S 1, S 2,... Sn when the liquid crystal device 100 (described later) is normally driven. A precharge circuit 201 having a precharge function, a sampling circuit 301 that samples the image signal VID and supplies it to the plurality of data lines 35, a data line driving circuit 101, and a scanning line driving circuit 104 are formed. Yes.
Note that the precharge circuit 201 can have an inspection function for performing various electrical inspections such as an open or disconnection inspection and a short circuit inspection of the data line 35 and the TFT 30 of the pixel portion connected thereto. That is, it is possible to apply a test voltage to the data line 35 or to pass a test current so as to perform a predetermined type of electrical test.

The scanning line driving circuit 104 supplies scanning signals Y1 to the scanning lines 31 (gate electrode lines) at a predetermined timing based on power supplied from an external control circuit (not shown), a reference clock CLY and its inverted clock (/ CLY), and the like. Y2,..., Ym are applied in a line-sequential manner in a pulse manner.
In the data line driving circuit 101, the scanning line driving circuit 104 applies the scanning signals Y1, Y2,..., Ym based on the power supplied from the external control circuit, the reference clock CLX and its inverted clock (/ CLX), and the like. In synchronization with the timing, the sampling circuit driving signals SH1, SH2,..., SHn are supplied to the sampling circuit 301 via the sampling circuit driving signal line 306 for each data line 35 for each image signal line 304 at a predetermined timing.

The precharge circuit 201 includes, for example, a TFT 202 as a switching element for each data line 35, the precharge signal line 204 is connected to the drain or source electrode of the TFT 202, and the precharge circuit drive signal line 206 is connected to the TFT 202. Connected to the gate electrode.
During normal driving, a predetermined voltage required for writing the precharge signal NRS from an external power source (not shown) is supplied via the precharge signal line 204, and each data line is supplied via the precharge circuit drive signal line 206. The precharge circuit drive signal NRG is supplied from the external control circuit so that the precharge signal NRS is written at a timing preceding the pixel signals S1, S2,.
The precharge circuit 201 preferably supplies a precharge signal NRS (image auxiliary signal) corresponding to the image signals S1, S2,.
The sampling circuit 301 includes a TFT 302 for each data line 35, the image signal line 304 is connected to the source electrode of the TFT 302, and the sampling circuit drive signal line 306 is connected to the gate electrode of the TFT 302. When the image signal VID is input via the image signal line 304, it is sampled. That is, when the sampling circuit drive signals SH1, SH2,..., SHn are input from the data line drive circuit 101 via the sampling circuit drive signal line 306, the image signal VID is sampled for each of the image signal lines 304 and the data line 35 is sampled. Are sequentially applied.

  As described above, in this embodiment, the data lines 35 are sequentially selected one by one. However, a plurality of data lines 35 may be selected simultaneously.

2 is a plan view of the TFT substrate as viewed from the side of the counter substrate together with the components formed thereon, and FIG. 3 is a cross-sectional view taken along the line HH ′ of FIG.
2 and 3, in the liquid crystal device 100 according to the present embodiment, the TFT substrate 1 on which the TFT 30 is formed and the counter substrate 2 are arranged to face each other.

  A liquid crystal layer 150 is sealed between the TFT substrate 1 and the counter substrate 2, and the TFT substrate 1 and the counter substrate 2 are mutually connected by a seal material 152 provided in a seal region located around the image display region 1 a. It is glued to. The sealing material 152 is made of, for example, a thermosetting resin, heat and photo-curing resin, photo-curing resin, UV-curing resin, or the like for bonding the two substrates, and after being applied on the TFT substrate 1 in the manufacturing process, It is cured by heating, light irradiation, light irradiation, ultraviolet irradiation or the like.

  Vertical conduction members 106 are provided at the four corners of the counter substrate 2, and electrical conduction is established between the vertical conduction terminals provided on the TFT substrate 1 and the counter electrode 12 provided on the counter substrate 2. .

  2 and 3, a light-shielding light-shielding film 153 that defines the image display region 1a is provided on the counter substrate 2 side in parallel with the inside of the seal region where the sealant 152 is disposed. Needless to say, the light shielding film 153 may be provided on the TFT substrate 1 side. A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT substrate 1 on the outer side of the sealing area where the sealing material 152 is arranged in the peripheral area extending around the image display area 1a. The scanning line driving circuit 104 is provided along two sides adjacent to the one side. Further, on the remaining side of the TFT substrate 1, a plurality of wirings 105 are provided for connecting between the scanning line driving circuits 104 provided on both sides of the image display region 1a.

  In FIG. 3, on the TFT substrate 1, an alignment film is formed on the pixel electrode 11 after the pixel switching TFT, the scanning line, the data line, and the like are formed. On the other hand, an alignment film is formed on the counter substrate 2 in the uppermost layer portion in addition to the counter electrode 12. The liquid crystal layer 150 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films.

  In the region on the TFT substrate 1 below the light shielding film 153, a sampling circuit (not shown) (see reference numeral 301 in FIG. 1) is provided. The sampling circuit 301 samples the image signal VID on the image signal line in accordance with the sampling circuit drive signals SH1, SH2,..., SHn supplied from the data line drive circuit 101, and supplies them to the data line 35 of each pixel. It has become.

Next, with reference to FIGS. 4 to 7, a driving method that is a main part of the inspection method of the electro-optical device according to the first embodiment will be described. 4 and 5 illustrate a special driving method for inspection which is a main part of the inspection method of the present invention, and FIGS. 6 and 7 illustrate a normal driving method for comparison with FIGS. 4 and 5.
Here, the liquid crystal device as the electro-optical device becomes bright (displays white) in a state where no voltage is applied to the liquid crystal pixels (that is, voltage is off), and darkens (displays in black) when a voltage is applied (voltage is on). It will be described as a normally white mode.

First, normal driving will be described with reference to FIGS.
FIG. 6A shows a pixel applied voltage whose polarity is inverted every 1 vertical scanning period (hereinafter referred to as 1 V) held in the storage capacitor 70 after being applied to the pixel for a 1H writing period, and FIG. The counter electrode voltage whose polarity is inverted in synchronization with the polarity inversion of a) is shown.

At the time of normal driving, as shown in FIG. 7, the transfer start signal DY is set to a high level for a period of 1H, for example, so that the high level period is sequentially set as scanning signals Y1, Y2,. In such a state that the scanning lines are sequentially turned on, pixel signals are written in the 1H period for the pixels on the scanning lines that are turned on, and the written data is The pixel is stored in the storage capacitor 70 for a period of 1 V until the next frame. As shown in FIG. 6A, in the 1H period in which the pixel signal is written, in the initial period T in the 1H period, the precharge signal from the precharge circuit 201 passes through the data line 35 as a switching element. Applied to the source of the TFT 30. At this time, 7.5 V is written as the precharge voltage. After the precharge period T, the sampling circuit 301 samples the image signal VID according to the sampling circuit drive signals SH1, SH2,..., SHn from the data line drive circuit 101, and outputs the pixel signals S1, S2,. By supplying the data line 35 as Sn, writing to the pixel is performed. If the resistance value between the source and drain of the TFT 30 is normal (appropriate), the pixel voltage written to the pixel is in the remaining period until the 1H period ends as shown by the solid line S in FIG. Writing is performed. After the writing in the 1H period, the written data is held in the pixel storage capacitor 70 for a 1V period until the next frame. Actually, the voltage held in this pixel is a curve that gradually leaks and gradually decreases as shown by the solid line in FIG.

  However, even if the same precharge signal write operation and the same pixel signal write operation are performed in the 1H period, if the resistance value between the source and the drain is slightly higher than the appropriate value depending on the pixel, FIG. As shown by the dotted line U), the pixel gradually rises from the initial minimum value of 2.5 V in the 1H period and reaches the write potential (raster voltage) of the normal pixel S in the final part of the 1H period. White display (bright spot) does not occur. This is because if the raster voltage has been reached within the period of 1H, the storage capacitor 70 thereafter holds the pixel voltage above a certain level for a period of 1V, resulting in black display. In other words, during normal driving, even if it is a defective pixel, the voltage value slightly decreases with time if it is once written above a certain voltage (voltage necessary for black display) by pixel writing within the 1H period. A voltage close to that voltage is maintained until the end of the 1V period after the end of the 1H period, and as a result of maintaining the black display state, it is not known that the normal drive is defective.

Next, with reference to FIGS. 4 and 5, the special drive in the inspection method for the electro-optical device according to the first embodiment will be described.
FIG. 4 is a waveform diagram of the pixel applied voltage for explaining the inspection method for the electro-optical device according to the first embodiment of the invention. (a) is a waveform of a pixel application voltage whose polarity is inverted every horizontal scanning period (hereinafter referred to as 1H) applied to the pixel, and (b) is a counter electrode voltage whose polarity is inverted in synchronization with the polarity inversion of (a). The waveform is shown.

  In the apparatus shown in FIG. 1, in order to perform the special drive shown in FIG. 4, the pixel signal S1, S2,..., Sn is supplied to the data line 35 as the image signal VID at a predetermined level (for example, black level or halftone). Level) DC signal may be supplied to the sampling circuit 301 via the image signal line 304 and supplied to the data line 35 as pixel signals S1, S2,..., Sn sampled from the sampling circuit 301. Alternatively, for example, a precharge signal NRS of black level or halftone level is supplied to the precharge circuit 201 and supplied to the data line 35 as pixel signals S1, S2,..., Sn sampled from the precharge circuit 201. Also good.

  FIG. 5 shows a transfer start signal and scanning signals Y1, Y2,..., Ym for simultaneously turning on all scanning lines prior to applying the pixel signal to the pixel electrode in the electro-optical device of FIG. . In order to simultaneously turn on all the scanning lines, the scanning signals Y1, Y2,..., Ym may be simultaneously set to the high level. To realize this with the apparatus of FIG. .

  That is, in the liquid crystal device of FIG. 1, by setting the transfer start signal DY to a high level for a period of 1H, for example, the high level period is sequentially set as scanning signals Y1, Y2,. Since the transfer operation is performed (see FIG. 7), this operation principle is used. In other words, during the time when the display defect of the liquid crystal device is being inspected, the transfer start signal DY is maintained at a high level so that the high level period is sequentially transferred to the scanning signals Y1, Y2,. As a result, in the first one frame period (corresponding to one vertical scanning period), the rising timing of the scanning signals Y1, Y2,..., Ym is delayed by 1H as shown by the solid line in FIG. Since the transfer start signal DY is maintained at a high level, the scanning signals Y1, Y2,..., Ym in the second and subsequent frames are all simultaneously high as indicated by the solid line including the dotted line portion in FIG. It is assumed that it is standing up to the level.

  In a state where all the scanning lines are turned on in this way, as shown in FIG. 4A, the same signal having a predetermined level that reverses the polarity every 1H is supplied to the data line as the pixel voltage and written to the pixel. Here, the pixel refers to a portion including the pixel electrode 11 on the TFT substrate 1, the counter electrode 12 on the counter substrate 2, and the liquid crystal 150 interposed between these two electrodes. If the resistance value between the source and drain of the TFT 30 is normal (proper), the pixel voltage applied to the source of the TFT 30 as the switching element from the data line is a signal level of ± 2.5 V centered on the voltage 5 V (maximum) A pixel voltage having a value of 7.5 V and a minimum value of 2.5 V is normally written into the pixel during the 1H period, and a pixel voltage with the same polarity inverted is normally written into the pixel during the next 1H period. It will be.

  However, even if the same pixel signal of the same level is supplied to the data line, depending on the pixel, if the resistance value between the source and the drain is slightly higher than the appropriate value, the first 1H period as shown by the alternate long and short dash line Q is shown. A voltage that finally reaches the maximum value of 7.5V is applied to the pixel at the final part of the 1H rising gradually from the minimum value of 2.5V, and in the next 1H period, the rising time constant (in which the polarity is similarly reversed) However, the pixel voltage indicated by the alternate long and short dash line Q having the opposite polarity is applied to the pixel.

  Furthermore, even if the same pixel signal of the same level is supplied to the data line, if the resistance value between the source and the drain is a defective pixel that is much higher than the appropriate value, the voltage 5V is the center as shown by the dotted line R. A pixel voltage having a dull waveform with a small vertical width is applied to the pixel.

  The display brightness (monochrome display) in the image display area 1a (FIG. 2) is determined by the magnitude of the difference between the counter electrode voltage and the pixel applied voltage. In practice, the integrated value of the dull waveforms Q and R is the effective value that determines the brightness. As the waveform becomes duller, for example, the waveform R becomes brighter (brightened) because the difference between the counter electrode voltage and the pixel applied voltage in each 1H period is small, and is easily detected as a defective pixel. . In the waveform Q, the dullness is smaller than that in the waveform R, and a voltage reaching a maximum value of 7.5 V is applied to the pixel in the final portion of the 1H period. However, the effective voltage for writing is higher than that in the normal pixel P. Small and bright pixels with a certain brightness. Therefore, in the case of Q, it can be determined that the pixel is a defective pixel but has a slightly high degree of defect.

  Therefore, when the black level signal is supplied to all the pixels as the pixel signal by the special driving shown in FIG. If there is a normal pixel and white (bright spot) display, it can be determined as a defective pixel. Further, if the brightness level is slightly bright, it can be determined that the brightness is slightly poor.

  By supplying a signal of a halftone level between black and white levels to all the pixels as a pixel signal, it becomes easier to distinguish a difference in the degree of defect of a defective pixel than when a black level signal is supplied to all the pixels. In other words, even if there are some defects in all black, the black display is difficult to distinguish. In the halftone, there is an advantage that even a relatively small defect can be easily distinguished on display.

  Further, by making the polarity inversion period (cycle) of the pixel signal applied to the pixels variable, it is possible to detect a difference in the degree of display defects. That is, when a signal whose polarity is inverted every predetermined period (cycle) is written to the pixel, the resistance value between the source and drain of the TFT as a switching element is reduced by performing a special drive with a variable write voltage period. For example, if the polarity reversal period (cycle) is shortened, the writing time is shortened even in a pixel whose resistance value is slightly higher than the normal value, resulting in insufficient writing of the pixel voltage. Therefore, detection as a defective pixel becomes possible.

FIG. 8 is a schematic configuration diagram of the inspection apparatus for projecting the liquid crystal device as shown in FIG. 2 as viewed from the side.
In FIG. 8, reference numeral 14 denotes a liquid crystal device inspection apparatus, which includes a projector 15 and a screen 16.
Here, an example of a modularized liquid crystal device, that is, an inspection device that inspects display defects such as point defects of the liquid crystal device 100 in which a flexible printed circuit board (hereinafter, FPC) 120 or the like is attached and accommodated in a case will be described. To do.

  In FIG. 8, for convenience of explanation, the light emitted from the projection lens is projected onto a screen that is horizontally installed upward. You may project on the installed screen.

  The inspection drive signal is supplied to the probe unit 51 through a cable from a panel drive device 52 installed outside the projector 15.

    The inspection device 14 transmits light from the lamp 17 serving as a light source through the lens unit 18 including a plurality of lenses and filters into the casing 60 and transmits the light through the liquid crystal device 100 on which the inspection image is displayed. Direction), an inspection optical system 40 that forms an inspection optical path for projecting onto the screen 16 through an optical member such as a projection lens 19, a stage 22 that holds the liquid crystal device 100 vertically on the inspection optical path, and a predetermined inspection drive. A panel driving device 52 that generates a signal, a panel driving device 52 that generates a predetermined inspection driving signal, and a liquid crystal device 100 that is held on the inspection optical path from the panel driving device 52 for displaying a predetermined inspection image. The probe unit 51 as a signal transmission means for transmitting the inspection signal and the liquid crystal device 100 held on the inspection optical path are heated or cooled to liquid. And a temperature adjusting device 58 adjusting the temperature of the device 100, main part with a screen 16 which is adjustably arranged its position in front of the housing 60 is formed. The stage 22 can move the liquid crystal device to a placement position (two-dot chain line portion) and an inspection position by an air cylinder 26 via a pneumatic control device (not shown).

  The predetermined inspection driving signal controls the data line driving circuit 101 and the scanning line driving circuit 104 to perform the entire scanning when the liquid crystal device 100 is specially driven as shown in FIG. This refers to a drive signal including a control signal and a clock signal for generating pixel signals whose polarities are inverted every predetermined period smaller than one vertical scanning period (1V) and supplying them to all the pixels. .

  The inspection optical system 40 includes a lamp 17 as a light source that emits inspection light such as white light in the vertical direction at one end portion of the housing 60, and an actual machine on which the liquid crystal device 100 to be inspected is mounted from the lamp 17. The lens unit 18 that generates inspection light having the same characteristics and emits upward in the vertical direction, and the liquid crystal device 100 in which the inspection light in the vertical direction emitted from the lens unit 18 is held horizontally on the stage 22 are left in the vertical direction. A projection lens 19 as an optical member that is interposed on a vertical inspection optical path and adjusts the focal length of the inspection light so as to be transmitted and projected onto the screen 16 in front of the housing 60. The inspection light transmitted through the liquid crystal device 100 in the vertical direction and projected by the projection lens 19 is projected onto the screen 16 disposed above the housing 60 in the vertical direction without changing the direction. You have me.

The stage 22 is configured by a rectangular plate-like member that is horizontally supported in the housing 60 via a stage operation mechanism unit 25 (described later), and the liquid crystal device 100 to be inspected is mounted on the front surface of the stage 22. A recess 20 is provided for placement.
The liquid crystal device 100 may have various sizes from 0.5 to 1.4 inches, for example, and the screen 16 has a size of about 4035 inches diagonal, for example.
Further, the projection lens 19 can also be exchanged, and the projection lens 19 having a different focal length can be used according to the size of the liquid crystal device 100.

  In this case, the concave portion 20 has a shape that substantially conforms to the external shape of the liquid crystal device 100, and further has a positioning member such as a pin (not shown) in its main portion, thereby positioning the placed liquid crystal device 100 at a predetermined position. It is designed to hold horizontally. The stage 22 can be used by exchanging one having a recess 20 corresponding to the size of the liquid crystal device 100, or by placing various sizes of liquid crystal devices in the recess 20 of a predetermined size using an adapter. Also good.

The stage 22 has an opening 21 for guiding inspection light to a display unit (not shown) of the liquid crystal device 100 placed in the recess 20.
Further, a flange portion 23 for detachably mounting the stage 22 to the stage operation mechanism portion 25 is provided at the base portion of the stage 22.

The stage operation mechanism unit 25 includes an air cylinder 26 that is fixed horizontally in a housing 60. An air pressure control device (not shown) is connected to the air cylinder 26 so that the piston rod 27 of the air cylinder 26 can be expanded and contracted horizontally in the housing 60 by the operating air pressure supplied from the air pressure control device. It has become.
A stage mounting portion 28 is fixed to the tip of the piston rod 27, and the stage 22 is detachably fastened to the stage mounting portion 28 via the flange portion 23.

  In this case, as indicated by the solid line in FIG. 8, when the piston rod 27 is in the contracted position, the stage 22 is inserted between the lens unit 18 and the projection lens 19 so that the display unit of the liquid crystal device 100 is placed on the inspection optical path. On the other hand, as shown by a two-dot chain line in FIG. 8, the specifications of each part are set so that the display part of the liquid crystal device 100 is retracted from the inspection optical path when the piston rod 27 is in the extended position. . As shown in the figure, when the piston rod 27 is extended before the start of inspection or after the end of the inspection, the stage 22 pushes open the opening / closing window 29 provided in the housing 60, so that the liquid crystal device 100 is attached to the housing 60. It is exposed to the outside and can be replaced or removed.

The probe unit 51 is supported in the housing 60 via a probe operation mechanism unit 53 (described later), and corresponds to each electrode terminal (not shown) arranged on the FPC 120 of the liquid crystal device 100. It has a plurality of probes 50 that can be electrically connected.
The probe unit 51 transmits a predetermined special driving signal for inspection generated by the panel driving device 52 to the liquid crystal device 100 when each probe 50 is electrically connected to each electrode terminal on the FPC 120. It has become. The predetermined special driving signal for inspection is a driving signal for causing the liquid crystal device 100 to display all pixels in black or all pixels in halftone.
The probe operation mechanism unit 53 includes an air cylinder 54 that is vertically fixed in the housing 60. A pneumatic control device (not shown) is connected to the air cylinder 54, and the piston rod 55 of the air cylinder 54 is expanded and contracted vertically in the housing 60 by the operating air pressure supplied from the pneumatic control device. It has become.

A probe unit mounting portion 56 is fixed to the tip of the piston rod 55, and the probe unit 51 is fastened and fixed to the probe unit mounting portion 56 so as to be detachable.
In this case, the probe unit 51 is opposed to each electrode terminal on the FPC 120 of the liquid crystal device 100 in which each probe 50 is held on the inspection optical path, and the FPC 120 when the piston rod 55 is in the extended position (front side in the drawing). Each probe 50 is electrically connected to each upper electrode terminal (see FIG. 8), and each probe 50 is separated from each electrode terminal on the FPC 120 when the piston rod 55 is in the contracted position (upward in the figure). As shown (not shown), the specifications of each part are set.

  The temperature adjustment device 58 adjusts the temperature of the liquid crystal device 100 by blowing warm air or cold air to the liquid crystal device 100 held on the inspection optical path. The blower device 59 and drive control of the blower device 59 are controlled. A control unit (not shown) for performing and a temperature sensor (not shown) embedded in the stage 22 in the vicinity of the liquid crystal device 100 are configured. The control unit is provided with a control panel (not shown) for setting the temperature and the like, and the control unit determines the amount of hot air or cold air blown from the blower device 59 based on the temperature detected by the temperature sensor and its temperature. As a result, the liquid crystal device 100 is controlled to a desired set temperature.

Next, the operation of the inspection apparatus 14 configured as described above will be described.
First, the operator moves the stage 22 to a retracted position from the inspection optical path by operating the air cylinder 26 via an air pressure control device (not shown). In this state, the liquid crystal device 100 to be inspected is positioned and placed on the recess 20 of the stage 22.
Thereafter, the operator operates the air cylinder 26 via the pneumatic control device to move the stage 22 to the insertion position between the lens unit 18 and the projection lens 19. Accordingly, the display unit of the liquid crystal device 100 placed on the stage 22 is held at a predetermined position on the inspection optical path.

Thereafter, the operator moves the probe unit 51 by operating the air cylinder 54 via the air pressure control device, and the probe 50 of the probe unit 51 is placed on each electrode terminal arranged on the FPC 120 of the liquid crystal device 100. Connect electrically.
Thereafter, the operator operates the panel driving device 52 and applies a predetermined inspection driving signal to the liquid crystal device 100 to perform special driving (see FIGS. 4 and 5). As a result, a predetermined inspection image is projected on the screen 16 above the housing 60. As the predetermined inspection image, all pixel black display or all pixel halftone display is projected.

  Thereafter, the operator visually inspects the projected image (all pixel black display or all pixel halftone display) on the screen when the liquid crystal device 100 is specially driven by a predetermined inspection drive signal to inspect for the presence of a bright spot. If there is a bright spot (white display), the pixel can be determined as a defective pixel.

Further, the operator can observe the inspection image under a predetermined environmental temperature condition by operating the temperature adjusting device 58 and managing the temperature of the liquid crystal device 100.
For example, when applied to a reflective electro-optical panel such as LCOS, the inspection apparatus of the present invention can be used by arranging the lamp 17 and the lens unit 18 above the stage together with a half mirror and the like. .

  In the above-described embodiment, the case where the electro-optical device is applied to a projector liquid crystal device that projects and displays a liquid crystal panel has been described. However, the present invention is not limited to this, and the electroluminescence device, in particular, the organic electroluminescence device. , Inorganic electroluminescence devices, etc., plasma display devices, devices using electron-emitting devices (Field Emission Display and Surface-Conduction Electron-Emitter Display, etc.), LED (Light Emitting Diode) display devices, electrophoretic display devices, thin cathode ray tubes It can be applied to inspection apparatuses for various electro-optical devices such as a small television using a liquid crystal shutter or the like, and a device using a digital micromirror device (DMD).

FIG. 3 is a diagram showing a configuration of an active matrix substrate in a liquid crystal device to which the electro-optical device inspection method according to the first embodiment of the present invention is applied. The top view which looked at the TFT substrate from the opposite substrate side with each component formed on it. H-H 'sectional drawing of FIG. FIG. 4 is a waveform diagram of a pixel applied voltage during special driving, illustrating an inspection method for the electro-optical device according to the first embodiment of the invention. The timing chart which shows the transfer start signal and scanning signal at the time of special drive. FIG. 6 is a waveform diagram of a pixel applied voltage during normal driving of the electro-optical device. 6 is a timing chart showing a transfer start signal and a scanning signal during normal driving. The schematic block diagram of the test | inspection apparatus which performs the projection test | inspection of a liquid crystal device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... TFT substrate, 2 ... Counter substrate, 11 ... Pixel electrode, 14 ... Inspection apparatus, 15 ... Projector, 30 ... TFT (switching element), 31 ... Scan line, 35 ... Data line, 70 ... Storage capacity, 100 ... Liquid crystal device 101 ... Data line driving circuit 104 ... Scanning line driving circuit 150 ... Liquid crystal layer 201 ... Precharge circuit 202 ... TFT 204 Precharge signal line 206 ... Precharge circuit drive signal line 301 Sampling circuit 302 ... TFT 304 ... Image signal line 306 ... Sampling circuit drive signal line

Claims (6)

Electricity comprising a plurality of scanning lines for supplying scanning signals, a plurality of data lines for supplying pixel signals obtained by sampling image signals to the pixels, and a plurality of switching elements provided corresponding to the intersections of the scanning lines and the data lines An inspection method for an optical device,
A scanning signal is applied from the scanning line to all gates of the switching element to turn on both ends of the switching element at the same time, and a predetermined period smaller than one vertical scanning period from the data line to one end of the switching element. An inspection method for an electro-optical device, wherein a pixel signal whose polarity is inverted every time is given to turn on all pixels.   The electro-optical device inspection method according to claim 1, wherein the pixel signal is a signal having the same level in all data lines.   The electro-optical device inspection method according to claim 2, wherein a signal level of the pixel signal is a halftone level.   2. The inspection method for an electro-optical device according to claim 1, wherein the polarity inversion period is variable, and a difference in display defect level can be detected.   5. The inspection method for an electro-optical device according to claim 1, wherein the polarity reversal is reversed at least every predetermined number of horizontal scanning periods equal to or greater than one. 6. The inspection method for an electro-optical device according to claim 1, wherein the polarity inversion is inverted in units of pixels in addition to inversion every predetermined number of horizontal scanning periods of at least one or more.

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