JP2004333663A - Device for inspecting panel for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten time for image processing without lowering inspection accuracy. <P>SOLUTION: The device for inspecting a panel for display is characterized by containing a stage to receive the panel for display to be inspected, line sensors each of which comprises a plurality of sensor elements aligned at least in a first direction parallel to the display panel received on the stage, a transferring mechanism to transfer the line sensors in a second direction intersecting the first direction and in parallel to the display panel, an area sensor to take a picture of the display panel from the side of the line sensors and a driving mechanism to transfer the area sensor in reference to the display panel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for inspecting a display panel such as a liquid crystal display panel, and more particularly to an inspection apparatus suitable for a lighting inspection of a display panel.
[0002]
[Prior art]
A display panel such as a liquid crystal display panel is turned on to inspect its quality. Such a lighting inspection includes a point defect inspection for inspecting the presence or absence of a luminance defect (that is, a point defect) of each display pixel of the display panel, and an uneven defect inspection for inspecting luminance unevenness in a predetermined region of the display panel. There is.
[0003]
Such a lighting inspection includes a visual inspection in which the lit display panel is visually inspected by an operator and an electric signal obtained by photographing the lit display panel with a sensor such as a line sensor or an area sensor. (Image processing).
[0004]
In general, an automatic inspection apparatus captures an image using a sensor, such as a CCD camera, in which light-receiving elements (sensor elements) are arranged in a line or a matrix, processes an output signal of the sensor, and thereby determines the quality of the display panel. Has been determined.
[0005]
As one of such automatic lighting inspection apparatuses, an area sensor such as a CCD television camera in which a large number of sensor elements are arranged in a matrix in a plane parallel to a display panel on a stage (Patent Document 1). And a line sensor such as a CCD line sensor in which a large number of sensor elements are arranged in one direction (Y direction) in a plane parallel to a display panel on a stage (Patent Document 2).
[0006]
[Patent Document 1]
JP-A-9-258157
[Patent Document 2]
JP-A-11-142288 [0008]
In these inspection devices, with the display panel turned on, the display panel is photographed by a sensor, and image processing is performed using the obtained electric signal to determine the quality of the display panel. I have.
[0009]
[Problem to be solved]
However, since the resolution of the area sensor is low, the inspection accuracy is low, and thus the area sensor is not suitable for a point defect inspection requiring high inspection accuracy. On the other hand, the line sensor is suitable for the point defect inspection because of its high resolution, but takes time for the process of taking in the sensor output and the image processing using the taken-in signal.
[0010]
An object of the present invention is to reduce image processing time without lowering inspection accuracy.
[0011]
[Solutions, actions, and effects]
An inspection apparatus according to the present invention includes a stage for receiving a display panel to be inspected, a line sensor in which a plurality of sensor elements are arranged in at least a first direction parallel to the display panel received on the stage, and A moving mechanism for moving the line sensor in a second direction intersecting the first direction and parallel to the display panel, and an area sensor for photographing the display panel from the line sensor side And a drive mechanism for moving the area sensor with respect to the display panel.
[0012]
The area sensor has difficulty in recognizing a bright spot defect address and color and is difficult to obtain a high resolution, but can perform image capture and image processing at high speed, and has a signal-to-noise ratio (S / N) can be increased. For this reason, at the time of the unevenness defect inspection, the display panel is photographed by the area sensor, and the presence or absence of uneven brightness is determined using the output signal of the area sensor.
[0013]
On the other hand, the line sensor requires a long time for capturing an image and performing image processing, but can obtain a high resolution. For this reason, at the time of the point defect inspection, the display panel is photographed by the line sensor, and the presence or absence of the point defect is determined using the output signal of the line sensor.
[0014]
If the area sensor and the line sensor are provided as described above, the display panel can be photographed by the area sensor or the line sensor according to the type of inspection, and the presence / absence of a defect can be determined. And the image processing time is reduced.
[0015]
The drive mechanism moves the area sensor three-dimensionally, that is, in the first direction, the second direction, and a third direction that intersects the first and second directions. It is good also as a mechanism which can do it.
[0016]
The inspection apparatus further includes a capturing circuit that captures an output signal of the line sensor, an image processing circuit that performs image processing using the signal captured by the capturing circuit, and captures an output signal of the area sensor to perform image processing. In addition, a main control processing device that controls the capturing circuit and the image processing circuit can be included. By doing so, the image capturing time and the image processing time are further reduced.
[0017]
The inspection device further includes a plurality of the line sensors arranged in the first direction, and a plurality of the capturing circuits and a plurality of image processing circuits individually corresponding to the line sensors. You may. By doing so, the time for capturing the image and the time for processing the image are further reduced.
[0018]
The inspection device may further include a probe unit including a plurality of probes pressed by the electrodes of the display panel.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIG. 1 to FIG. 5, an inspection apparatus 10 is used for an automatic lighting inspection of the panel 12 as a display panel 12 to be inspected from a liquid crystal display panel having a rectangular shape. In the illustrated example, the panel 12 has a plurality of electrodes on each of two adjacent sides.
[0020]
In the following description, two directions orthogonal to each other (directions of adjacent edges (rectangular sides) of the rectangular panel 12) in a plane parallel to the display panel 12 disposed at the inspection position of the inspection apparatus 10 are represented by X. The direction perpendicular to the panel 12 is called the Z direction.
[0021]
The inspection device 10 includes a stage 14 that is arranged in a frame (not shown) so as to be movable in the horizontal direction. The stage 14 is an inspection stage including a chuck top for receiving the panel 12 and a backlight unit for illuminating the panel 12 from behind.
[0022]
For this reason, the stage 14 can move the received panel 12 two-dimensionally in the X and Y directions parallel to the panel 12, and can move the panel 12 in the Z direction perpendicular to the panel 12. 12 can be rotated angularly about the Z axis perpendicular to it.
[0023]
The stage 14 is movable between a transfer position where the panel 12 is transferred to a transfer device such as a transfer robot and an inspection position where a lighting inspection of the panel 12 is performed.
[0024]
Above the stage 14, a substrate 16 is horizontally mounted on a frame. The substrate 16 has a rectangular hole 18 through which the stage 14 moved to the inspection position can be seen from above. Hole 18 has a larger planar dimension than panel 12.
[0025]
The probe unit 20 is arranged on the substrate 16 at a position corresponding to the rectangular hole 18. The probe unit 20 attaches a plurality of known probe blocks 22 in which a plurality of probes individually pressed to the electrodes of the panel 12 are arranged in a block to a plate-shaped probe base 24, and attaches the probe base 24 to the lower surface of the substrate 16. Attached.
[0026]
The probe base 24 has a rectangular hole 25 smaller than the hole 18 of the substrate 16 and larger than the panel 12, and is attached to the substrate 16 so that the hole 25 is coaxial with the hole 18.
[0027]
The probe blocks 22 are divided into two probe block groups respectively corresponding to two adjacent sides of the rectangle. The probe blocks 22 of each probe block group are attached to the probe base 24 so that the tips (tips) of the probes are aligned.
[0028]
The inspection apparatus 10 also includes a plurality of line sensors 26 arranged on the substrate 16 in a state of being aligned in a line in the Y direction so as to linearly photograph the panel 12, And an area sensor 28 disposed above.
[0029]
Each line sensor 26 is a known sensor such as a CCD line sensor in which a plurality of sensor elements are arranged in at least three rows adjacent to each other in the X direction and extending in the Y direction, and the X, Y, and Z moving mechanisms 30, It is moved three-dimensionally by 32 and 34.
[0030]
The X moving mechanism 30 uses a pair of linear guides each having a stator 36 having a long stator area and a mover 38 movably assembled to the stator 36, and the stator 36 has a hole. The stator region is attached to the upper surface of the substrate 16 so that the stator region extends in parallel in the X direction in a state where the stator regions oppose each other with the interposition therebetween. The mover 38 is supported by the stator 36 so as to be movable in the X direction.
[0031]
The Z movement mechanism 34 also uses a pair of linear guides each having a stator 40 having a long stator area and a mover 42 movably assembled to the stator 40, and the stator 40 has a hole. The stator 40 is attached to the mover 38 of the X moving mechanism 30 so that the stator region extends in the Z direction in a state where the stator regions face each other with the gap 18 therebetween. The mover 42 is supported by the stator 40 so as to be movable in the Z direction.
[0032]
The Y moving mechanism 32 uses a linear guide having a stator 44 having a long stator region and a plurality of movers 46 movably assembled to the stator 44, and the stator 44 extends in the Y direction. As described above, the stator is supported by the mover of the Z moving mechanism. The mover 46 is supported by the stator 44 so as to be individually movable in the Y direction.
[0033]
The area sensor 28 is a known sensor in which a plurality of sensor elements are arranged in a matrix like a CCD television camera, and is moved in three directions of X, Y, and Z with respect to the stage 14 by a driving mechanism 48.
[0034]
The drive mechanism 48 includes a Z drive mechanism 50 attached to a frame (not shown) to move the area sensor 28 in the Z direction, and an X drive mechanism attached to the Z drive mechanism to move the area sensor 28 in the X direction. 52, and a Y drive mechanism 54 attached to the X drive mechanism 52 to move the area sensor 28 in the Y direction. Such a drive mechanism 48 can also be configured using three or more linear guides.
[0035]
Each line sensor 26 is supported by the mover 46 of the Y moving mechanism 32 with its light incident side facing the panel 12 on the stage 14. The area sensor 28 is also supported by the Y drive mechanism 54 of the drive mechanism 48 with its light incident side facing the panel 12 on the stage 14.
[0036]
Each of the linear guides described above is a known drive mechanism that is commercially available under the name of a linear motor table or the like. Such a drive mechanism generally includes a stator having a plurality of coils arranged in one direction, such as a linear motor, and one or more movers assembled to the stator so as to be movable in the one direction. By supplying AC power to the mover, the mover can be moved relative to the stator, and can be maintained at a predetermined position. The stator has a guide that regulates the moving direction of the mover.
[0037]
Referring to FIG. 10, main control processing device 60 controls driver 62 to move area sensor 28 to X, Y, and Z with respect to panel 12 on stage 14. Thus, the X, Y and Z driving mechanisms 52, 54 and 50 of the driving mechanism 48 are individually driven by the driver 62.
[0038]
Main control processor 60 also controls drivers 64, 66 and 68 to move line sensor 26 relative to panel 12 in the X, Y and Z directions. Thus, the X, Y and Z moving mechanisms 30, 32 and 34 are driven by the drivers 64, 66 and 68, respectively. Although not shown, the driver 66 of the Y moving mechanism 32 is configured to move the movers 46 individually.
[0039]
The main control processor 60 is further provided with a plurality of capturing circuits 70 provided for each line sensor 26 to capture the output signal of the line sensor 26, and for each line sensor 26 for performing image processing of the captured signal. A plurality of image processing circuits 72 are controlled.
[0040]
A general computer can be used as the main control processing device 60, the capture circuit 70, and the image processing circuit 72. In particular, it is preferable to use, as the main control processing device 60, input devices such as a keyboard and a mouse, and a computer having a display device.
[0041]
However, the functions of the processing device and the processing circuit may be performed by a single computer, or the control of the driving mechanism 48 and the moving mechanisms 30, 32, and 34 may be performed by another processing device that cooperates with the main control processing device 60. It may be performed. Further, the stage 14 may be controlled by any of the main control processing device 60, the other processing device, and the processing device dedicated to the stage.
[0042]
The line sensor 26 requires a long time to capture an image and perform image processing, but can obtain a high resolution. Therefore, at the time of the point defect inspection, the panel 12 is photographed by the line sensor 26, and the presence or absence of a point defect is determined using the output signal of the line sensor 26.
[0043]
On the other hand, the area sensor 28 has difficulty in recognizing a luminescent spot defect address and color, and it is difficult to obtain high resolution. The noise-to-noise ratio (S / N) can be increased. For this reason, at the time of the uneven defect inspection, the panel 12 is photographed by the area sensor 28, and the presence or absence of uneven luminance is determined using the output signal of the area sensor 28.
[0044]
Next, the operation of the inspection device 10 will be described.
[0045]
Prior to the inspection, positioning of the panel 12 with respect to the probe unit 26 is performed. This positioning is performed, for example, by taking the panel 12 on the stage 14 away from the probe block 22 and photographing a plurality of locations such as alignment marks on the panel 12 with the line sensor 26 or the area sensor 28 moved to a predetermined position. Then, the operation is performed by moving the panel 12 in the X and Y directions by the stage 14 so that those portions are located at predetermined positions in the captured image.
[0046]
In the case of the stage 14 having a function of angularly rotating the panel 12 about the Z axis, the panel 12 is mounted on the stage 14 so that the arrangement direction of the display pixels matches the arrangement direction of the sensor elements of the line sensor 26. Rotates angularly about the Z axis.
[0047]
Next, the panel 12 is raised by the stage 14, and the electrodes of the panel 12 are pressed by the probes of the probe block 22, so that the panel 12 is energized and the backlight in the stage 14 is turned on. In this state, the uneven defect inspection and the point defect inspection are performed.
[0048]
At the time of inspecting the uneven defect, as shown in FIG. 5, the X, Y, and Z moving mechanisms 30, 32, and 34 retract the line sensor 26 to a position where the line sensor 26 does not hinder the area sensor 28 from photographing the panel 12.
[0049]
In the above state, first, the driver 62 is driven by the main control processing device 60 to drive the drive mechanism 48 so that the panel 12 is located at a predetermined position in the photographing area of the area sensor 28.
[0050]
Next, the main control processing device 60 captures the output signal of the area sensor 28, performs image processing based on the captured signal, and determines whether or not there is uneven brightness.
[0051]
The unevenness defect inspection relates to unevenness in brightness of the entire panel, and can be performed, for example, by determining whether or not the brightness deviation between predetermined regions in an image exceeds an allowable value. This determination result is stored in the memory attached to main control processing device 60.
[0052]
When inspecting a point defect, each movable element 46 of the Y moving mechanism 32 is moved in the Y direction by the driver 66 so that each line sensor 26 photographs a display pixel in a predetermined area of the panel 12 in the Y direction. The movable element 42 of the Z moving mechanism 34 is moved in the Z direction by the driver 68 so that pixels are photographed by a plurality of sensor pixels, and the Y moving mechanism 32 and thus the movable element 46 are moved in the Z direction.
[0053]
The number of sensor pixels assigned to one display pixel can be three, for example, as shown in FIGS. 7, 8, and 9. In the case of color, one display pixel 56 can be a set of R, G, and B primary color pixels, that is, a set of primary color pixels necessary to represent one color. However, each primary color pixel may be used as the display pixel 56.
[0054]
7, 8, and 9, three display pixels 56 are captured by one line sensor 26. However, in practice, since each line sensor 26 has a plurality of n sensor elements arranged in the Y direction, each line sensor 26 captures 3 × n = r display pixels 56.
[0055]
In the above state, the driver 64 is controlled by the main control processing device 60 to move the line sensor 26 at least once from one end to the other end in the X direction by the X moving mechanism 30 as shown in FIG. Thus, the image of the panel 12 is captured by the line sensor 26.
[0056]
When the panel 12 is photographed by the line sensor 26, each capturing circuit 70 is controlled by the main control processing device 60 to capture the output signal of the corresponding line sensor 26 for each column of sensor elements. The signal captured by each capture circuit 70 is supplied to the corresponding image processing circuit 72 via the main control processing device 60.
[0057]
Each image processing circuit 72 performs image processing for each display element row based on an input signal for each sensor element row, and determines whether or not each display element has a luminance defect. The luminance defect can be performed, for example, by determining whether the luminance of the display element is within a predetermined allowable value.
[0058]
When inspecting a display panel 12 of a type different from the standard display panel 12, the panel size (dimensions) of the panel 12, the size of the display pixels 56, the arrangement pitch of the display pixels 56, the display in the Y direction At least one operation selected from the group of increasing or decreasing the line sensor 26, adjusting the position of each line sensor 26 in the Y direction, and adjusting the position of the line sensor 26 in the Z direction is performed according to the number of pixels or the like.
[0059]
For example, as shown in FIG. 7A, a standard number of display pixels 56 having the number of pixels and the arrangement pitch at which one line of display pixels 56 can be simultaneously photographed in the Y direction by the standard number of line sensors 26. In the case of the display panel 12, the Y movement mechanism 32 is vertically moved by the Z movement mechanism 34, and the line sensor 26 is positioned with respect to the panel 12 so that one display pixel 56 is photographed by a plurality of sensor elements. .
[0060]
However, as shown in FIG. 7B, the number of display pixels is the same as that of the standard panel 12, but when inspecting the display panel 12a in which the arrangement pitch of the display pixels 56 is large, the Y moving mechanism 32 has the Z movement. While being raised by the moving mechanism 34, each line sensor 26 is moved in the Y direction by the Y moving mechanism 32, and the line sensor 26 is separated from the panel 12a so that one display pixel 56 is photographed by a plurality of sensor elements. .
[0061]
Also, as shown in FIGS. 8B and 8C, a display panel 12b having the same panel size as the standard panel 12 shown in FIG. Then, the inspection apparatus 10 is driven as follows.
[0062]
First, as shown in FIG. 8B, the Y moving mechanism 32 is moved down by the Z moving mechanism 34 to divide the display pixels 56 into two groups of r, and each display pixel 56 of one group is divided into two groups. The line sensor 26 is approached to the panel 12a so as to capture an image with a plurality of sensor elements. In this state, the line sensor 26 is moved once in the X direction together with the Y movement mechanism 32 by the X movement mechanism 30 to photograph the panel 12b.
[0063]
Next, as shown in FIG. 8C, the line sensor 26 is moved by the Y moving mechanism 32 by the size of the pixel of r so that the line sensor 26 photographs the next group of display pixels 56 with a plurality of sensor elements. It is moved in the Y direction. In this state, the line sensor 26 is moved once in the X direction together with the Y movement mechanism 32 by the X movement mechanism 30 to photograph the panel 12b.
[0064]
Further, as shown in FIG. 9 (B), although the arrangement pitch of the display pixels is the same as that of the standard panel 12 shown in FIG. When inspecting the panel 12c, the inspection device 10 is driven as follows.
[0065]
First, as shown in FIG. 9B, one or more line sensors 26a are added according to the panel size and the number of display pixels, so that each display pixel 56 is photographed by a plurality of sensor elements. Is moved in the Y and Z directions with respect to the panel 12a by the Y and Z moving mechanisms 32 and. In this state, the line sensor 26 is moved once in the X direction together with the Y movement mechanism 32 by the X movement mechanism 30 to photograph the panel 12b.
[0066]
As described above, the positions of the plurality of line sensors 26 in the Y direction can be individually changed, and the positions of the line sensors 26 in the Z direction can be changed. As a result, even if the number of sensor elements to be assigned to one display element 56 is the same or different, it is possible to inspect different types of display panels.
[0067]
When the line sensor 26 and the area sensor 28 are provided as described above, the panel 12 can be photographed by the line sensor 26 or the area sensor 28 according to the type of inspection, and the presence or absence of a defect can be determined. The image processing time is shortened without reduction.
[0068]
Further, the image processing apparatus includes a capture circuit 70 and an image processing circuit 72 for the line sensor 26, and a main control processing device that captures an output signal of the area sensor 28 to perform image processing and controls the capture circuit and the image processing circuit. In this case, the image capturing time and the image processing time are further reduced.
[0069]
Further, if the capturing circuit 70 and the image processing circuit 72 are provided for each line sensor 26, the capturing time of the image and the image processing time are further reduced.
[0070]
The present invention can be applied not only to inspection of a liquid crystal display panel, but also to inspection of other display panels such as a display panel using a light emitting diode and an organic EL.
[0071]
The present invention is not limited to the above embodiments, and can be variously modified without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an inspection apparatus according to the present invention, with a part thereof cut away.
FIG. 2 is a perspective view of the inspection apparatus shown in FIG.
FIG. 3 is a plan view of the inspection device shown in FIG.
FIG. 4 is a cross-sectional view taken along line 4-4 in FIG.
FIG. 5 is a cross-sectional view taken along line 5-5 in FIG.
FIG. 6 is a diagram showing a state where a line sensor in the apparatus shown in FIG. 1 is moved in the X direction.
FIG. 7 is a diagram showing a relationship between a line sensor and a display pixel for explaining the operation of the device shown in FIG. 1;
FIG. 8 is a diagram illustrating a relationship between a line sensor and a display pixel for explaining another operation of the device illustrated in FIG. 1;
FIG. 9 is a diagram showing a relationship between a line sensor and display pixels for explaining still another operation of the device shown in FIG. 1;
FIG. 10 is a block diagram showing one embodiment of an electric circuit in the device shown in FIG. 1;
[Explanation of symbols]
Reference Signs List 10 Inspection device 12, 12a, 12b, 12c Display panel 14 Stage 16 Board 18, 25 Hole 20 Probe unit 22 Probe block 24 Probe base 26 Line sensor 26a Additional line sensor 28 Area sensor 30, 32, 34 Line sensor X, Y, Z moving mechanisms 36, 40, 44 Moving mechanism stators 38, 42, 46 Moving mechanism mover 48 Area sensor driving mechanisms 50, 52, 54 Area sensor Z, X, Y drive mechanism 56 Display pixel

Claims (5)

A stage for receiving a display panel to be inspected,
A line sensor in which a plurality of sensor elements are arranged in at least a first direction parallel to the display panel received by the stage;
A moving mechanism for moving the line sensor in a second direction intersecting the first direction and in a second direction parallel to the display panel;
An area sensor for photographing the display panel from the side of the line sensor,
A drive mechanism for moving the area sensor with respect to the display panel. The drive mechanism according to claim 1, wherein the drive mechanism moves the area sensor in the first direction, the second direction, and a third direction that intersects the first and second directions. Inspection equipment. A capturing circuit that captures an output signal of the line sensor; an image processing circuit that performs image processing using the signal captured by the capturing circuit; and an image signal that captures an output signal of the area sensor to perform image processing. The inspection device according to claim 1, further comprising a circuit and a main control processing device that controls the image processing circuit. Further, a plurality of the line sensors are arranged in the first direction, and a plurality of the capture circuits and a plurality of image processing circuits respectively corresponding to the line sensors are provided. 3. The inspection device according to 3. The inspection device according to any one of claims 1 to 4, further comprising a probe unit including a plurality of probes that are pressed against the electrodes of the display panel.

Images