CN1249426C - Detecting method and device for display board - Google Patents

Abstract

To enable defects to be detected for a display substrate without using a polarizing filter of a complex structure or a driving mechanism. The inspection method includes obtaining information of true defects in the display substrate by means of a first image signal by a first light beam traveling from the display substrate to a photodetector and a second image signal by a second light beam for which the first light beam is passed through a polarizing filter having a polarizing angle different at 90[deg.] against a polarizing angle by the display substrate.

Description

Inspection method and device of display panel

Technical field

The present invention relates to a method and device for inspecting display panels such as liquid crystal display panels and glass substrates.

Background technique

For example, the display panel of the liquid crystal display panel will be flashed to check whether the pixels containing the liquid crystal components are correct. As one of such automatic flash inspection methods and devices, the technology disclosed in Patent Document 1 is known.

Patent Document 1: Japanese Patent Application Laid-Open No. 10-160628.

In this prior art, a polarizing filter capable of changing the polarization direction is arranged between the CCD camera and the display panel, and when the light transmitted through the display panel passes through the polarizing filter and is detected by the CCD camera, the The polarization direction caused by the polarizing filter is changed sequentially, and the polarization-dependent parts such as protrusions and foreign objects that are easy to be seen are detected.

Contents of Invention

In this prior art, since the light passing through the display panel is often required to pass through a polarizing filter, it is necessary to change the polarization angle caused by the polarizing filter when obtaining image information with a CCD camera, and at the same time detect the polarity of the display panel itself. defect. Therefore, the configuration of the polarizing filter itself or the driving mechanism is complicated and expensive.

The purpose of the present invention is to detect the defect of the display panel without using a complicated polarizing filter or a driving mechanism.

The inspection method of the present invention includes: adopting the first image signal formed by the first light directed from the display panel to the light detection device; and passing the first light with respect to the polarization angle formed by the display panel. The second image signal formed by the second light of the polarizing filter with different polarization angles of 90° is used to obtain the real defect information of the aforementioned display panel.

The inspection device related to the present invention comprises: a chuck top that accepts the display panel to be inspected; a detection unit equipped with several probes that are energized to the aforementioned display panel; and detects light from the aforementioned display panel. A photodetection device as an electrical signal; a polarization filter with a different polarization angle of 90° relative to the polarization angle formed by the aforementioned display panel, and configured as a polarizing filter that can enter and exit the path of light from the aforementioned display panel toward the aforementioned photodetection device; And using the first image signal formed by the first light that does not pass through the aforementioned polarizing filter and the second image signal formed by the second light that passes through the aforementioned polarizing filter among the lights from the aforementioned display panel to obtain the aforementioned display An image processing device for real defect information of boards.

The first light can be obtained by replacing the polarizing filter to a position outside the path of the first light. On the other hand, the second light can be obtained by replacing the position where the passage of the first light has been blocked by the polarizing filter. The first and second image signals are obtained by detecting the first and second light, respectively, by a light detection device such as a CCD camera.

The first image signal formed by the first light without a polarizing filter contains the substrate signal (including the real defect signal) showing the state of the display panel itself; and the presence of foreign objects such as dust and scratches that cause random reflection of light foreign body signal. However, the second image signal formed by the second light passing through the polarizing filter contains foreign object signals but does not contain substrate signals.

Therefore, the real defect information of the display panel can be obtained by using the foreign object signal in the second image signal and removing the foreign object signal in the first image signal.

According to the present invention, it is only necessary to selectively replace the polarizing filter between the position outside the path forming the first light and the position blocking the first light, so it is not necessary to use a polarizing filter and a driving mechanism with a complicated structure. Real defects of the display panel are detected.

The aforementioned real defect information can be obtained by subtracting the first image signal and the second image signal. The aforementioned display panel may be a glass substrate with or without a liquid crystal component, and may contain a polarizer facing the glass substrate.

The inspection device further includes a replacement mechanism for selectively replacing the polarizing filter between a first position not located on the path and a second position located on the path on the path of the first light. In addition, the top of the holder may also have a backlight device for irradiating light to the received display panel.

Description of drawings

Fig. 1 is a diagram showing an embodiment of the inspection device of the present invention;

FIG. 2 is an explanatory diagram of a polarization state of light;

Fig. 3 is another explanatory diagram of the polarization state of light;

Fig. 4 is still another explanatory diagram of the polarization state of light.

Detailed ways

Referring to FIG. 1 for description, the inspection device 10 uses a liquid crystal display panel enclosed in a liquid crystal module as a display panel 12 . Although the display panel 12 has a rectangular planar shape in the following description, it may have other planar shapes. The display panel 12 has a plurality of electrodes for energizing for driving at positions corresponding to at least two sides of the rectangle.

The inspection device 10 includes: the clamp top 14 that accepts the display panel 12 to be inspected; the inspection table 16 that replaces the clamp top 14; the detection unit 18 that is energized with the accepted display panel 12; Light is detected as the photodetector 20 of electrical signal; Be configured as the polarizing filter 22 that can enter and exit the optical path between the display panel 12 and the photodetector 20; The drive mechanism 24 that enters and exits the optical path between 20; the image processing device 26 that obtains the real defect information of the display panel 12 by using the output signal of the photodetector 20; and the shield case (shield case) 28 that accommodates these mechanical devices .

The holder top 14 is known to have several suction grooves for vacuum-suctioning the received display panel 12 , and accommodates a backlight device that irradiates white light from below on the received display panel 12 .

The inspection table 16, in addition to three-dimensionally moving the base top 14 in the X, Y, and Z directions, simultaneously forms an X, Y, and The platform of Z and θ.

The detection unit 18 is configured to have a plurality of probe blocks 32 having a plurality of contacts 30 individually pressed to the electrodes of the display panel 12, arranged in a rectangular shape corresponding to the planar shape of the display panel 12 in the central area. The substrate 36 of the opening 34 .

The contact 30 is a probe type probe in the illustrated example, but any other form such as a blade type, a pogopin type, or a bump type may be used. Each probe block 32 is mounted on the upper surface of the substrate 36 in a state where the tip (point of a needle) of the contact 30 passes through the opening 34 of the substrate 36 and protrudes below the substrate 36 .

The light detector 20 is a known camera such as a CCD camera and a line sensor (line sensor), which detects the light passing through the display panel 12, and generates an electrical signal showing the image of the display panel 12, and outputs it to the image Processing means 26.

The polarizing filter 22 has a different polarization angle of 90° relative to the polarization angle of the light passing through the display panel 12 (preventing the passage of light that vibrates in the same direction as the polarization angle of the light formed by the display panel 12), and it is obtained from the display panel. 12 , among the light incident on the photodetector 20 , the light vibrating in different directions by 90° with respect to the vibration direction of the light passing through the display panel 12 passes.

The polarizing filter 22 is selectively moved between a first position where the polarizing filter 22 does not block the first light from the display panel 12 toward the photodetector 20, and a second position where it is blocked by the driving mechanism 24. .

During inspection, the display panel 12 is placed on the top 14 of the holder, and the light from the backlight unit passes through the display panel 12 and each electrode is pressed to the contact 30 while maintaining the backlight unit. In this state, the polarizing filter 22 is selectively replaced between the first position and the second position by the driving mechanism 24 .

The image processing device 26 is based on the output signal of the photodetector 20 when the polarizing filter 22 is moved to the first position; image signal, and the real defect information of the display panel 12 is obtained by using the two image signals.

When the polarizing filter 22 is moved to the first position, the first light directed from the display panel 12 toward the photodetector 20 enters the photodetector 20 without passing through the polarizing filter 22 . Therefore, the output signal of the photodetector 20 will become a first signal formed by the first light not passing through the polarizing filter 22, and the image processing device 26 will generate a first image signal corresponding to the first signal.

When the polarizing filter 22 moves to the second position, since the first light from the display panel 12 toward the photodetector 20 is incident on the polarizing filter 22, the second light passing through the optical polarizing filter 22 is incident on the detector. 20. Therefore, the output signal of the photodetector 20 becomes a second signal formed by the second light, and the image processing device 26 generates a second image signal corresponding to the second signal.

The first image signal formed by the first light that does not pass through the polarizing filter 22 includes a substrate signal (including a real defect signal) that shows the state of the display panel 12 itself; and shows dust and scratches that cause light scattering or random reflection, etc. , Foreign body signal of the presence of foreign matter.

But, the 2nd picture signal that the 2nd light that passes through polarizing filter 22 forms, though allow polarizing filter 22 to pass through to the light that vibrates in 90 ° different directions with respect to the vibration direction of the first light, but because stop and the 1st light Passage of light vibrating in the same direction as the light vibration direction contains foreign matter signals due to light scattering or random reflection, but does not include substrate signals including true defect signals.

Specifically, as shown in FIG. 2 , in the case where two polarizing films 40 and 42 whose polarization angles of allowing light to pass are different from each other at 90° are respectively arranged on the lower surface of the liquid crystal module layer 44 and the upper display panel 12 Make the following instructions.

First, the light 46 from the backlight unit in the top portion 14 of the holder contains light components vibrating in 360° directions around the optical axis in addition to white light.

When the light 46 passes through the polarizing film 40 through which the light component vibrating in the horizontal direction passes, the light passing through the polarizing film 40 becomes the light of the component vibrating in the horizontal direction.

Next, the light passing through the polarizing film 40 passes through the liquid crystal element layer 44 and is polarized to vibrate in the vertical direction.

Next, the light passing through the liquid crystal element layer 44 passes through the polarizing film 42 through which the light component vibrating in the vertical direction passes. Thereby, the light 48 passing through the display panel 12 becomes light vibrating in the vertical direction.

The light 48 passing through the display panel 12 is directly incident on the photodetector 20 because the polarizing filter 22 is replaced in one of the first and second positions, or through the light that prevents vibration in the vertical direction (passing through the display panel 12). light) passes through the polarizing filter 22 and enters the photodetector 20.

When the polarizing filter 22 is replaced to the first position, since the light 48 does not pass through the polarizing filter 22 , the light incident on the photodetector 20 includes the light showing the state of the display panel 12 itself.

In addition, when foreign matter 50 such as dust or scratches that causes random reflection of light exists on display panel 12 , light passing through display panel 12 or passed light is scattered or randomly reflected by foreign matter 50 . Therefore, the scattered or randomly reflected light 52 caused by the foreign object 50 also enters the photodetector 20 .

In contrast to this, when the polarizing filter 22 is replaced to the second position, all the light towards the photodetector 20 will be incident on the polarizing filter 22, and since the polarizing filter 22 has the polarization angle formed by the display panel 12 and 90° different polarization angles, so although the light 48 will be blocked by the polarizing filter 22, the light 54 of the component vibrating in the horizontal direction in the scattered or randomly reflected light 52 will pass through the polarizing filter 22. Therefore, although light vibrating in the horizontal direction enters the photodetector 20 , light vibrating in the vertical direction through the display panel 12 does not enter.

To sum up, the image processing device 26, when the polarizing filter 22 is replaced at the first position, will generate substrate signals (including real defect signals) that show the state of the display panel 12 itself; The 1st image signal of the foreign object signal that the foreign object exists. In contrast, when the polarizing filter 22 is replaced at the second position, the image processing device 26 will generate a second image signal that does not include the substrate signal, although the foreign object signal is included.

The image processing device 26 uses the foreign object signal in the second image signal to remove the foreign object signal in the first image signal, thereby obtaining the true defect information of the display panel 12 . Specifically, the image processing device 26 obtains actual defect information of the display panel 12 by subtracting the second image signal from the first image signal, and stores the obtained defect information in the memory.

In other words, the light 52 directly incident on the photodetector 20 from the foreign object 50 and the light 54 passing through the polarizing filter 22 in the light 52 exist at the same coordinate position in the inspection device 10 and the two image signals. Therefore, by subtracting the second image signal from the first image signal, the foreign object signal can be removed to obtain defect information showing the actual defect position of the display panel 12 .

The acquired defect information will be used in the not-shown partitioning device to distinguish between normal display panels without defects and defective display panels with defects.

As described above, according to the inspection device 10, the polarizing filter 22 is selectively positioned between the first position outside the passage of light from the display panel 12 toward the photodetector 20 and the second position blocking the passage of the light. Replacement, so as to obtain the real defect information of the display panel 12, so the real defect of the display panel 12 can be detected without using a polarizing filter with a complicated structure and its driving mechanism.

As shown in Figure 3, when only one side of the liquid crystal component layer 44 (being the bottom in the figure) has a display panel with a polarizing film 40, the light 46 vibrating vertically and horizontally will be removed by the polarizing film 40 at first vibrating in the vertical direction. light component, and the light of the light component vibrating in the horizontal direction passes through the polarizing film 40 .

Secondly, the light passing through the polarizing film 40 directs the light component polarized in the liquid crystal element layer 44 to vibrate in the vertical direction from the display panel 12 to the light detector 20 . Therefore, the image processing device 26 will generate the first image signal when the polarizing filter 22 is moved to the first position, and will generate the second image signal when it is moved to the second position.

The present invention is not only not affected by foreign matter existing on the surface of the display panel 12, but also as shown in FIG. The real defect information can be obtained due to the influence of

The present invention is applicable not only to an inspection technique using a backlight unit that irradiates light onto the display panel 12, but also to an inspection technique that uses reflected light by placing a mirror behind the display panel 12.

The present invention is not limited to the above embodiments, and various changes can be made as long as they do not deviate from the gist of the present invention.

Description of component symbols:

10 Inspection device 12 Display board

14 Top of clamp seat 16 Examination table

18 detection units 20 light detectors

22 polarizing filter 24 driving mechanism

26 image processing devices 28 shielding cabinets

30 contacts 32 detection blocks

34 openings 36 substrates

40, 42 polarizing film 44 liquid crystal component layer

46, 48, 54 light 50 foreign matter

52 random reflection light

Claims (6)

1. the inspection method of a display board is characterized in that, comprises step:

The set of polarisation filter is become from the position of display board outside the light path of the 1st light of optical detection device, and the portrait treating apparatus produces the 1st portrait signal according to the detected electric signal corresponding to described the 1st light of optical detection device;

The light path that described polarisation filter set is become described the 1st light of blocking is to form the position of the 2nd light, and described portrait treating apparatus produces the 2nd portrait signal according to the detected electric signal corresponding to described the 2nd light of optical detection device;

Wherein, described portrait treating apparatus described the 1st portrait signal that will obtain and described the 2nd portrait signal reduce and handle to obtain real defect information; And

Wherein, the polarisation angular difference of the polarization angle of described polarisation filter and described display board is 90 °.

2. the method for claim 1 is characterized in that, wherein, aforementioned display board comprises the Liquid crystal module layer.

3. the method for claim 1 is characterized in that, wherein, aforementioned display board comprises the glass substrate that does not contain Liquid crystal module, and the Polarizer relative with this glass substrate.

4. the testing fixture of a display board is characterized in that, comprises:

The holder top of the display board that acceptance should be checked;

Probe unit with several probes that make described display board energising;

Detection is from the light of described display board and export the optical detection device of electric signal;

Be configured to the polarisation filter that can in the light path between described display board and the described optical detection device, pass in and out, 90 ° of the polarisation angular differences of the polarization angle of described polarisation filter and described display board;

The set of polarisation filter is being become from the position of display board outside the light path of the 1st light of optical detection device, produce the 1st portrait signal according to the detected electric signal of optical detection device corresponding to described the 1st light, described polarisation filter set is being become the light path of described the 1st light of blocking to form the position of the 2nd light, produce the 2nd portrait signal according to the detected electric signal of optical detection device, and described the 1st portrait signal that will obtain and described the 2nd portrait signal reduce the portrait treating apparatus of handling the real defect information of acquisition corresponding to described the 2nd light.

5. device as claimed in claim 4 is characterized in that, wherein, more comprises: make optionally the 1st position on the light path that is not positioned at aforementioned the 1st light of aforementioned polarisation filter; And be positioned at the displacement mechanism that replaces between the 2nd position on this light path.

6. as claim 4 or 5 described devices, it is characterized in that wherein, aforementioned holder top has the back lighting device that the display board of being accepted is given irradiates light.

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