JP5744640B2 - Brightening point defect blackening method of liquid crystal panel - Google Patents

Description

  The present invention relates to a blackening method and a blackening device for bright spot defects in a liquid crystal panel.

  In the liquid crystal panel, a defect called a bright spot defect may occur due to contamination of foreign matters in the manufacturing process. The bright spot defect is a defect that is visually recognized as a bright pixel even when a dark color such as black is displayed on the liquid crystal panel. Therefore, the bright spot defect is conspicuous, and the liquid crystal panel in which the bright spot defect is generated is often discarded as a defective product, which causes a decrease in yield in manufacturing the liquid crystal panel.

  As a method of correcting the bright spot defect in such a liquid crystal panel, conventionally, the color filter coloring material corresponding to the bright spot defective pixel of the liquid crystal panel is irradiated with a laser to blacken it, thereby making the bright spot defect conspicuous. There was a technology to eliminate it. As a laser irradiation method, there is a method of performing irradiation continuously (for example, Patent Document 1) or performing irradiation in a pulse shape (Patent Document 2).

JP-A-3-21928 JP 2008-170938 A (paragraphs 0044 and 0047)

  Among the laser irradiations described above, pulse lasers such as Q-switched lasers and mode-locked lasers can generate laser beams only with specific pulse widths and repetition frequencies determined by the laser light oscillator configuration. Therefore, the average output of the laser and the peak output of the laser cannot be adjusted independently. Therefore, when blackening the color filter colorant corresponding to the bright spot defective pixel, if the average output of the laser is increased to obtain a blackening level at which the bright spot is sufficiently shielded, the color filter may be destroyed. Peeling occurs, and the alignment film in the peripheral pixels of the bright spot defect pixel is thermally denatured, resulting in disturbance of liquid crystal alignment. As described above, when the pulse laser is used, there are problems that the color filter is broken or peeled off, and that a new display defect occurs in the peripheral pixels of the bright spot defective pixel.

  On the other hand, when a continuous wave laser is used, destruction of the color filter can be relatively suppressed, but heating suitable for blackening the bright spot cannot be performed. For this reason, heat may be applied more than necessary, and the alignment film in the peripheral pixels of the bright spot defective pixel is thermally denatured, and liquid crystal alignment is disturbed. As described above, even when a continuous wave laser is used, there still occurs a problem that a new display defect occurs in the peripheral pixels of the bright spot defective pixel.

  The present invention has been made to solve such a problem, and appropriate blackening of a bright spot without affecting the peripheral pixels of the bright spot defect pixel with respect to the bright spot defect in the liquid crystal panel. It is an object of the present invention to provide a blackening method and a blackening apparatus that can be used.

In order to achieve the above object, the present invention is configured as follows.
In other words, the bright spot defect blackening method for a liquid crystal panel according to one embodiment of the present invention scans the laser beam from the laser oscillator relative to the bright spot defective pixels formed in the color filter constituting the liquid crystal panel. In the method of blackening a bright spot defect in which the bright spot defect pixel is blacked by irradiation, the laser beam is scanned while modulating the irradiation output of the laser beam irradiated to the bright spot defective pixel.

  According to the bright spot defect blackening method for a liquid crystal panel according to one embodiment of the present invention, a sufficient amount of heat for blackening a bright spot defective pixel is obtained by modulating the output of a laser beam oscillated from a laser oscillator. In addition to being applied to the pixels, it is possible to prevent an excessive amount of heat from being applied to the color filter color material. Therefore, heat conduction to the peripheral pixels of the bright spot defective pixels can be prevented, and new display defects can be prevented from occurring in the peripheral pixels. Thus, it is possible to achieve both the blackening level sufficient for shielding the bright spot defect and the suppression of the liquid crystal alignment abnormality in the peripheral pixels of the blackening target pixel.

  Further, by correcting the bright spot defect using the above-described bright spot defect blackening method, it is possible to recycle the liquid crystal panel that has been discarded in the past, and to contribute to the improvement of the yield of the liquid crystal panel.

It is a figure which shows schematic structure of the bright spot defect blackening apparatus of the liquid crystal panel in Embodiment 1 of this invention. It is a figure which shows an example of the scanning path | route of the laser beam in the bright spot defect blackening apparatus shown in FIG. It is a figure which shows the other example of the scanning path | route of the laser beam in the bright spot defect blackening apparatus shown in FIG. It is a figure for demonstrating the example of the laser output modulation in the bright spot defect blackening apparatus shown in FIG. It is a figure for demonstrating the relationship between the laser output modulation in the bright spot defect blackening apparatus shown in FIG. 1, and the scan of a laser spot. It is a figure which shows schematic structure of the bright spot defect blackening apparatus of the liquid crystal panel in Embodiment 2 of this invention. It is a figure which shows the structure of the optical chopper with which the bright spot defect blackening apparatus shown in FIG. 6 is equipped. It is a figure for demonstrating the example of the laser output modulation using the optical chopper with which the bright spot defect blackening apparatus shown in FIG. 6 is equipped. It is a figure which shows schematic structure of the bright spot defect blackening apparatus of the liquid crystal panel in Embodiment 3 of this invention. It is a schematic sectional drawing of a liquid crystal module.

  A bright spot defect blackening method and apparatus for a liquid crystal panel, which is an embodiment of the present invention, will be described below with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals.

Embodiment 1 FIG.
FIG. 10 is a schematic cross-sectional view of the liquid crystal module 20 including the liquid crystal panel 15. In FIG. 10, the thickness of each element in the liquid crystal module 20 is illustrated to be significantly different from the actual ratio for the sake of explanation.

First, the liquid crystal module 20, particularly the liquid crystal panel 15 will be described.
The liquid crystal module 20 includes a liquid crystal panel 15, a backlight light source 12, a drive control board 17, a power source 18, and the like. The backlight light source 12 is disposed on the back side of the liquid crystal panel 15, and the liquid crystal panel 15 and the backlight light source 12 are electrically connected to the drive control board 17 and controlled in operation by a control device of the drive control board 17.

The liquid crystal panel 15 has a structure in which the liquid crystal 7 is sandwiched between the color filter substrate 13 and the TFT substrate 14.
The color filter substrate 13 is a color filter color material 1 that expresses a color by transmitting transmitted light in a specific wavelength range corresponding to red, green, and blue, a color filter substrate side polarizing plate 2, and a color filter substrate side glass. A substrate 3, a black matrix 4 disposed between adjacent pixels to block transmitted light, a counter electrode 5 for applying a voltage to the liquid crystal 7, and a color filter substrate side alignment for aligning the liquid crystal 7 in a specified direction And a film 6. A color filter coloring material 1 in which each pixel is divided by a black matrix 4 is sandwiched between a color filter substrate side glass substrate 3 and a counter electrode 5, and a color filter substrate side polarizing plate 2 is disposed on the color filter substrate side glass substrate 3. A color filter substrate-side alignment film 6 is provided on the counter electrode 5.

  The TFT substrate 14 (TFT: Thin Film Transistor) includes a TFT substrate side alignment film 8 for aligning the liquid crystal 7 in a specified direction, a TFT array 9 for controlling a voltage applied to the liquid crystal 7, and a TFT substrate side. It has a glass substrate 10 and a TFT substrate side polarizing plate 11. The TFT array 9 formed on the TFT substrate side glass substrate 10 is configured to be sandwiched between the TFT substrate side alignment film 8 and the TFT substrate side polarizing plate 11.

  Regarding the liquid crystal module 20 configured as described above, the bright spot defect blackening method and apparatus of the liquid crystal panel of the present embodiment is directed to the liquid crystal panel 15, and among the color filter color materials 1 constituting the liquid crystal panel 15, By irradiating a laser on the color filter colorant 1 of a pixel having a bright spot defect, that is, a bright spot defective pixel, this is blackened, and the bright spot defect on the liquid crystal panel 15 is shielded, that is, inconspicuous. Method and apparatus. First, a bright spot defect blackening device for a liquid crystal panel will be described below.

FIG. 1 shows a schematic configuration of a bright spot defect blackening apparatus 101 for a liquid crystal panel according to the first embodiment.
The bright spot defect blackening device 101 roughly includes a laser generator 31, an output modulator 70, and a liquid crystal panel moving device 50. Here, in this embodiment, the output modulation device 70 is connected to the laser generator 31 and is a device that modulates the irradiation output of the laser beam from the laser generator 31. The liquid crystal panel moving device 50 is a device for mounting the liquid crystal panel 15 to be blackened and moving the liquid crystal panel 15 in the X and Y directions perpendicular to each other with respect to the laser generator 31 in this embodiment. As described above, the liquid crystal panel 15 is moved in the present embodiment, but the liquid crystal panel moving device 50 may be any device that can move the laser generator 31 and the liquid crystal panel 15 in the X and Y directions relatively.

  The laser generator 31 basically includes a laser oscillator 17, a laser beam adjusting optical system 19, an aperture 20, a laser processing optical system 21, and a Z stage 23. In the present embodiment, the laser generator 31 and the λ / Has a two-wave plate 28.

The laser oscillator 17 will be described.
As described above, pulse lasers and continuous wave lasers have conventionally been used as laser oscillators for blackening of bright spot defects. For pulse lasers such as Q-switched lasers and mode-locked lasers, the pulse waveform and frequency range are determined by the oscillator configuration. That is, the peak output and average output of the laser pulse cannot be adjusted independently.
The applicant of the present application has attempted to blacken the bright spot defect using a Q-switched Nd: YAG laser or a mode-locked titanium sapphire laser. When these laser oscillators are used, if the laser average output is increased in order to obtain a blackening level sufficient for shielding bright spot defects, the peak output becomes too high. As a result, as described above, it has been found that there is a problem that a new display defect occurs in the peripheral pixels of the bright spot defective pixel.
On the other hand, when a continuous wave laser is used, the parameter relating to the laser output is only the average output. Even when a continuous wave laser is used, as in the case of a pulse laser, if the laser output is increased to obtain a sufficient blackening level, the alignment film of the peripheral pixels is heated by heat conduction to the peripheral pixels. Denatured and abnormal liquid crystal alignment occurred.

  Therefore, in the present embodiment, a laser whose output is modulated is generated by using a semiconductor laser (LD: Laser Diode) as the laser oscillator 17. Such a laser oscillator 17 is electrically connected to the output modulation device 70. In this embodiment, the output modulation device 70 is a laser drive power supply 18 capable of current modulation, and modulates laser output, in other words, laser drive current as shown in FIG. That is, the laser drive power source 18 optimizes the peak output P, the output modulation width W, the heating time τ, and the laser output modulation period T of the laser oscillator 17 to obtain a blackening level sufficient for shielding bright spot defects. In addition, it is possible to achieve coexistence with suppression of abnormal alignment of peripheral pixels. The output modulation width W has a minimum value of 0% and a maximum value of 100%. When the output modulation width W is 0%, output modulation is not actually performed. When the output modulation width W is 100%, the laser output changes from zero to the peak output P.

  Even if a solid-state laser such as an Nd: YAG laser is used, the laser output can be modulated by modulating the excitation light. However, in the case of a solid-state laser, if the excitation light is modulated, the thermal lens generated in the laser medium changes and the oscillator operation becomes unstable. Therefore, the laser oscillator 17 is preferably a semiconductor laser. In other words, the semiconductor laser has no thermal lens effect in the laser medium as compared with the solid-state laser, so that the operation of the laser oscillator at the time of laser output modulation is stabilized. Further, there is an advantage that the apparatus is simple and inexpensive, and the initial cost and running cost of the laser oscillator are inexpensive.

  The laser beam generated from the laser oscillator 17 driven and modulated by the laser driving power source 18 is shaped by the laser beam adjusting optical system 19. The laser beam adjusting optical system 19 is composed of a spherical lens, a cylindrical lens, a prism, and the like, and adjusts the laser beam to a beam diameter and a beam divergence angle suitable for blackening of a bright spot defective pixel.

  The laser beam adjusted in this way is shaped into the shape of the opening 20 by the opening 20. The opening 20 is, for example, circular or rectangular. The laser beam formed into a circle or a rectangle by the opening 20 is reduced and transferred onto the color filter substrate 13 of the liquid crystal panel 15 installed on the XY table 51 by the laser processing optical system 21.

  As shown in FIG. 10, the color filter substrate side polarizing plate 2 and the TFT substrate side polarizing plate 11 are attached to both surfaces of the liquid crystal panel 15, respectively. Although not clearly shown in FIG. 1, in the first embodiment, the polarizing plates 2 and 11 are blackened without being peeled off from the liquid crystal panel 15. A laser processing optical system 21 is installed on the Z stage 23 so that the laser beam emitted through the opening 20 is transferred to the color filter color material 1 on the liquid crystal panel 15. The distance between the processing optical system 21 and the liquid crystal panel 15 is adjusted.

  When the size of the laser spot in the color filter color material 1 of the liquid crystal panel 15 is as small as several μm, for example, when the distance between the laser processing optical system 21 and the liquid crystal panel 15 varies due to the inclination of the liquid crystal panel 15 or the like, the color The shape of the laser spot in the filter color material 1 changes and the laser processing becomes unstable. Therefore, for stable processing, the distance between the laser processing optical system 21 and the liquid crystal panel 15 is estimated by image processing or the like, and the Z stage 23 is automatically controlled based on the distance, thereby the laser processing optical system. It is effective to keep the distance between the liquid crystal panel 15 and the liquid crystal panel 15 constant.

  Therefore, in the first embodiment, the state of the liquid crystal panel 15 at the time of laser irradiation can be observed by adding the camera 22 to the laser processing optical system 21. Further, in order to enable observation, the XY table 51 is transmitted through the XY table 51 so that light from the observation light source 53 disposed on the opposite side of the mounting surface of the liquid crystal panel 15 in the XY table 51 can irradiate the liquid crystal panel 15. A hole 54 is provided. Even if the observation camera 22 and the observation light source 53 are omitted, the blackening process itself by laser irradiation is possible, but it is desirable to install the blackening process target pixel. It is also possible to install the observation light source 53 in the XY stage 51. As the observation light source 53, a light emitting diode (LED), a fluorescent lamp, or the like can be used.

  The movement of the liquid crystal panel 15 is controlled by a liquid crystal panel movement control device 52 installed in the bright spot defect blackening device 101.

  The shape of the laser spot on the color filter color material 1 of the liquid crystal panel 15 is determined by the shape of the opening 20 and the transfer magnification of the laser processing optical system 21. For example, if the opening 20 has a circular shape of φ150 μm and the transfer magnification is 1/50, the laser spot becomes a circular shape of φ3 μm. The size of the laser spot is optimized depending on the type of the liquid crystal panel 15 and the type of the color filter color material 1 by adjusting the size of the opening 20 or changing the transfer magnification of the laser processing optical system 21 as a processing parameter. can do. If the size of the laser spot is too large, the probability that the color filter color material 1 is not blackened and the color filter substrate 13 is damaged increases. On the other hand, if the size of the laser spot is too small, a blackening level sufficient for shielding the bright spot defect cannot be obtained. According to the applicant's test, the appropriate size of the laser spot is φ3 μm to φ5 μm.

  In order to blacken an entire pixel in the color filter color material 1 having a size of about several tens of μm or more with such a laser spot having a diameter of 3 to 5 μm, the movement control device 52 uses an XY table 51. Is driven to scan the laser spot relative to the liquid crystal panel 15. FIG. 2 shows an example of a laser spot scanning path during blackening. In the blackening target pixel (bright spot defect pixel) 60, laser irradiation is started at the processing start point 61, and the laser spot is scanned in a zigzag manner along the arrow in the drawing to the processing completion point 62. The laser irradiation is completed when reaching the point. A typical value for the scan speed is 40 μm / s. If the scanning speed is increased, the processing tact can be improved, but the blackening level is lowered. Therefore, the scanning speed may be determined by comparing and considering the processing tact and the blackening level necessary for shielding the bright spot defect.

  In addition, since the XY stage 51 stops at a place where the scan direction is changed, the changed place is irradiated with laser for a relatively long time. In order to prevent this, scanning may be performed as shown in FIG. 3 while turning on and off the laser irradiation. That is, in the pixel to be blackened (bright spot defective pixel) 60, laser irradiation is started at the first machining start point 63, and scanning is performed along the arrow to the first machining completion point 64, and the first machining completion point 64 is reached. At that time, the laser irradiation is stopped. Thereafter, the XY table 51 is driven to move to the second machining start point 65. Laser irradiation is started from the second machining start point 65, scanning is performed along the arrow to the second machining completion point 66, and the laser irradiation is stopped when the second machining completion point 66 is reached. Thereafter, the XY table 51 is driven to move to the third machining start point 67. By repeating this operation, the entire blackening target pixel 60 is blackened, and the blackening is completed when the scanning is completed up to the processing completion point 69.

  Further, when the bright spot defect blackening apparatus 101 performs blackening processing on the liquid crystal panel 15 in which the bright spot defect is found by the inspection process in the previous process of the bright spot defect blackening process, By transferring the location (address) of the bright spot defect found in the process to the bright spot defect blackening device 101, the bright spot defect pixel 60 can be positioned efficiently.

  As a method for placing the liquid crystal panel 15 on the XY table 51, it is conceivable that the color filter substrate 13 is opposed to the laser processing optical system 21 of the laser generator 31 and the TFT substrate 14 is opposed. Regardless of which surface of the color filter substrate 13 and the TFT substrate 14 is incident, the color filter color material 1 can be blackened. However, the effect on the blackening level and peripheral pixels obtained by the placement method may differ, and the placement method needs to be appropriately selected depending on the type of the liquid crystal panel 15 and the type of the color filter color material 1.

When the laser irradiation is performed with the polarizing plates 2 and 11 attached to the liquid crystal panel 15 as in the first embodiment, the direction of polarization in the polarizing plate on the laser incident side and the polarization in the laser beam. It is desirable to align with the direction. If these polarization directions are different, the laser beam may be absorbed by the polarizing plate 2 or the polarizing plate 11, damaging the polarizing plate made of resin, and a new display defect may occur. Because there is.
As a method of adjusting the direction of polarization in the laser beam, a λ / 2 wavelength plate 28 is inserted between the laser processing optical system 21 and the liquid crystal panel 15 in addition to the method of rotating the laser oscillator 17 itself around the optical axis. Then, there is a method of rotating the λ / 2 wavelength plate 28 around the optical axis.

The operation of the bright spot defect blackening apparatus 101 in the first embodiment configured as described above, that is, the bright spot defect blackening method, will be described in detail below mainly with respect to the operation control of the laser oscillator 17.
As described above, the laser drive current of the laser oscillator 17 is controlled by the laser drive power supply 18. That is, the laser drive power source 18 controls the laser output, that is, the laser drive current applied to the laser oscillator 17 as shown in FIG. 4, and sets the peak output P, the output modulation width W, the heating time τ, and the laser output modulation period T. Optimize. Here, if the laser drive current is completely zero, the overshoot of the laser output when the laser output is changed becomes large, and the operation of the semiconductor laser as the laser oscillator 17 becomes unstable. Therefore, at the time of laser output modulation, it is desirable not to make the laser drive current zero, but to make the current higher than the threshold value at which the semiconductor laser oscillates.

  Even when laser output modulation is performed as shown in FIG. 4, in reality, some alignment abnormality occurs in the vicinity of the area blackened by the laser. However, since the alignment abnormality occurrence region is suppressed by the laser output modulation by the laser driving power source 18, the alignment abnormality is hidden by the black matrix 4 (FIG. 10) between the blackening target pixel and the peripheral pixels. In addition, display defects due to abnormal orientation are not visually recognized.

  Blackening requires a certain amount of peak output P and heating time τ. However, if the peak output P is excessively increased, the color filter coloring material 1 of the pixel to be blackened is damaged and the orientation of the surrounding pixels is increased. The abnormality becomes large, and if the heating time τ is too long, the alignment abnormality of the peripheral pixels becomes large. Although it differs depending on the type of the liquid crystal panel 15 and the color of the color filter color material 1, it is good around peak output P: 40 mW, output modulation width W: 99%, heating time τ: 1 ms, and output modulation period T: 20 ms. Results were obtained. When the heating time τ is several nanoseconds to several microseconds, or when the peak output P is 10 mW or less, a sufficient blackening level cannot be obtained, the output modulation width W is 50% or less, and the heating time τ When the ratio between the output modulation period T and the output modulation period T satisfies any of ½ or more, the alignment abnormal region often extends to the peripheral pixels.

  Further, in the laser beam scan of the color filter color material 1, when the output modulation period T is set longer than the time Ts for scanning the distance corresponding to the laser spot diameter, that is, the laser spot diameter ÷ scan speed, one black In the pixel to be converted, there are a portion where the laser output is high and a portion where the laser output is low, and distribution occurs in the blackening level of the color filter color material 1.

  This phenomenon will be described with reference to FIG. FIG. 5 shows the relationship between laser output modulation and laser spot scanning according to the first embodiment. In the uppermost part of FIG. 5, the state of laser spot scanning is shown, the middle part shows an example of laser output modulation (when T <Ts), and the lowermost part shows an example of laser output modulation (T> Ts). In this case). The time Ts until the laser spot at the point a indicated by the dotted line at the uppermost stage in FIG. 5 is scanned to the point b indicated by the solid line separated by the laser spot diameter D is V , Ts = D ÷ V. In the case of T <Ts, as shown in the middle part of FIG. 5, since a plurality of laser output modulation periods are included between scans from point a to point b, a The blackening level from the point to the point b is made uniform.

  On the other hand, in the case of T> Ts, as shown in the lowermost stage of FIG. 5, only a laser output modulation period less than once is included in the scan from the point a to the point b. Therefore, in this example, the blackening level decreases from point a to point b.

  Therefore, the output modulation period T needs to be smaller than the time Ts. Further, in order to make the blackening process uniform, it is desirable that the output modulation period T is a value sufficiently smaller than the time Ts, specifically, a value of 1/5 or less.

  Further, processing conditions such as the peak output P, the output modulation width W, the heating time τ, and the output modulation period T are optimized for each type of the liquid crystal panel 15 and the type of the color filter color material 1. By preliminarily determining this condition and irradiating the liquid crystal panel 15 with actual bright spot defects with laser, a blackening level sufficient for shielding the bright spot defects can be achieved, and the periphery of the bright spot defects can be achieved. Occurrence of a new display defect of a pixel can be suppressed, and relief of the liquid crystal panel 15 having a bright spot defect can be achieved.

  The semiconductor laser in the laser oscillator 17 is available in various wavelengths from near-ultraviolet to infrared, but blue or red semiconductor lasers used for writing in laser display devices and optical storage media are used. Is possible. Depending on the relationship between the wavelength of the semiconductor laser and the color filter color material (red, green, or blue) in the pixel to be blackened, there was a concern that the transmittance is high and blackening cannot be performed efficiently. It has been found that if appropriate processing conditions are selected, blackening is possible regardless of the color of the color filter color material. Therefore, in order to simplify the configuration of the bright spot defect blackening device 101, it is possible to deal with the three color filter color materials 1 such as red, green, and blue with a single semiconductor laser. In the laser oscillator 17, it is desirable to use a single-chip semiconductor laser because it has a high light condensing property and can ensure reliability and life when using current modulation.

  In the bright spot defect blackening device 101 according to the first embodiment, since the laser drive current in the laser oscillator 17 is controlled by the laser drive power supply 18, the device configuration in the bright spot defect blackening device 101 is formed simply and inexpensively. can do.

Embodiment 2. FIG.
The second embodiment is different from the first embodiment only in the laser output modulation method. Therefore, here, the description will focus on the laser output modulation method, and the description of the same components will be omitted.
FIG. 6 shows a schematic configuration of the bright spot defect blackening device 102 of the liquid crystal panel in the second embodiment. In the bright spot defect blackening apparatus 101 according to the first embodiment, the laser driving power source 18 that enables current modulation in the laser oscillator 17 is used as the output modulation apparatus 70. However, the bright spot defect blackening according to the second embodiment is used. In the device 102, an external modulation element 40 is used as the output modulation device 70 in the laser optical path from the laser oscillator 17. Therefore, the bright spot defect blackening device 102 differs from the bright spot defect blackening device 101 in configuration in the laser generator 32 and the laser drive power supply 18-2.

  The laser generator 32 is different from the laser generator 31 only in that it has an external modulation element 40 as the output modulation device 70. As the external modulation element 40, an optical chopper, an AO (Acoustic-Optic) element, an EO (Electric-Optic) element, or the like can be used. In the second embodiment, an optical chopper is used.

  FIG. 7 shows a configuration diagram of the optical chopper. The optical chopper has a rotating plate 41 and a drive source 45. The rotating plate 41 is made of a circular plate, and a transmission portion 42 that transmits laser and a light shielding portion 43 that shields light are alternately provided along the circumference, and between the laser oscillator 17 and the laser beam adjusting optical system 19. It is arranged in the middle of the laser beam path 44. The optical chopper configured as described above can modulate the laser output emitted from the laser oscillator 17 by being rotated around the center point of the rotating plate 41 by the drive source 45. That is, when the transmitting portion 42 is positioned in the laser beam path 44, the laser beam passes through the rotating plate 41. When the light shielding portion 43 is positioned, the laser beam is blocked by the rotating plate 41, and the laser output at the processing point is zero. It becomes. An example of laser output modulation when an optical chopper is used is shown in FIG.

Since the output modulation device 70 includes the external modulation element 40 such as an optical chopper, the laser drive power supply 18-2 is different from the laser drive power supply 18 in the first embodiment.
Only the peak output P is adjusted for the laser oscillator 17.

  When the above-mentioned optical chopper is used, the beam diameter of the laser beam emitted from the laser oscillator 17 is a set size. Therefore, when transmission and light shielding are switched, a part of the laser beam is blocked and the rest Some will be transmitted. At the timing when the transmission and the light shielding are switched, the laser output at the processing point changes smoothly like a trigonometric function with respect to time as shown in FIG. The heating time τ and the output modulation period T in the laser output modulation can be adjusted by changing the angle between the transmission part 42 and the light shielding part 43 in the rotary plate 41 of the optical chopper and the rotation frequency of the rotary plate 41. . The peak output P is adjusted by the laser driving power source 18-2. Unlike the output modulation by the laser drive power supply 18 shown in the first embodiment, the laser drive power supply 18-2 does not freely adjust the waveform of the output modulation.

  Further, since the laser beam is completely blocked by the light shielding portion 43 of the rotating plate 41 in the optical chopper, the value corresponding to the output modulation width W in the output modulation by the current of the laser driving power source 18 shown in FIG. When an optical chopper is used, it becomes constant at 100%.

  On the other hand, when an AO element is used as the external modulation element 40, the output modulation width W is limited by the diffraction efficiency of the element. Although the output modulation width W can be brought close to 100% to some extent by using a plurality of elements, it is generally difficult to set the output modulation width W to 100%. However, compared with the optical chopper, the AO element has a complicated apparatus configuration and is expensive, but does not involve mechanical operation, and therefore, high-speed output modulation is possible. Further, since the diffraction efficiency can be changed by the voltage applied to the AO element, there is an advantage that the waveform of the output modulation can be set freely.

  Further, when an EO element is used as the external modulation element 40, the output modulation width W can be almost 100% unlike the AO element. When an EO element is used, the rotation angle of polarized light can be adjusted by the voltage applied to the EO element, and the transmittance of the EO element can be freely set, so that the output modulation speed is the same as that of the AO element and an optical chopper. The output modulation waveform can be freely set. However, a high voltage power supply is required for driving, and the apparatus is generally more expensive than an AO element.

  In addition, when the above-described external modulation element 40 is used, the output modulation is performed directly by the current, although there is a demerit that the apparatus is complicated and expensive as compared with the output modulation by the laser driving power source 18 in the first embodiment. There is a great merit that output modulation can be stably performed even for a solid-state laser such as an Nd: YAG laser which is difficult to perform.

  Further, due to the type of the liquid crystal panel 15 and the type of the color filter color material 1, a wavelength in the vicinity of a wavelength of 530 nm, a wavelength in the ultraviolet region shorter than 380 nm, or the like is required for laser blackening. The configuration of the second embodiment is particularly effective when it is inevitable to select a laser.

Embodiment 3 FIG.
In the first and second embodiments described above, the blackening process is performed with the polarizing plates 2 and 11 attached to the liquid crystal panel 15. In the third embodiment, the laser for the blackening process is used. In this embodiment, the blackening process is performed on the liquid crystal panel excluding at least the polarizing plate 2 or 11 on the laser incident surface side of the incident liquid crystal panel 15.

That is, when the blackening process is performed by applying a laser with the polarizing plates 2 and 11 attached as in the liquid crystal panel 15 shown in FIG. 10, the laser is emitted from the TFT substrate 14 side of the liquid crystal panel 15 in particular. When incident, the laser beam reflected by the wiring provided on the TFT substrate 14 damages the polarizing plate 11 to cause a new display defect, or the irradiated laser beam is scattered by the polarizing plate 11. The blackening process may not be performed. Therefore, such a problem can be solved by performing the blackening process after removing the polarizing plate on the laser incident surface side.
However, since there is no polarizing plate, the driving state of the liquid crystal panel cannot be observed in the bright spot defect blackening device, and the state of blackening treatment cannot be confirmed.

  Therefore, in the third embodiment, like the bright spot defect blackening device 103 whose schematic configuration is shown in FIG. 9, the camera 22 has a polarization function equivalent to that of the polarizing plates 2 and 11 used for display in the liquid crystal panel 15. A plate 81 is installed. In addition, the code | symbol 33 is attached | subjected as a laser generator which provided the polarizing plate 81 in the camera 22. FIG. 9 shows a configuration in which the polarizing plate 81 is provided for the bright spot defect blackening device 101 in the first embodiment, but the polarizing plate 81 is provided for the bright spot defect blackening device 102 in the second embodiment. You may take the structure which provided. The configuration other than the polarizing plate 81 is the same as the configuration in the first and second embodiments described above.

  The polarizing plate 81 is installed between the liquid crystal panel and the camera 22 and in a place not including the optical path of the laser irradiated to the liquid crystal panel. When the camera-side polarizing plate 81 is installed in the laser light path, the laser output in the color filter color material 1 changes depending on the direction of the polarized light of the laser or the transmitted polarized light of the polarizing plate. On the other hand, by installing the camera side polarizing plate 81 in a place not including the laser optical path as shown in FIG. 9, the laser output on the color filter can be made constant regardless of the polarization of the laser.

  Thus, by providing the camera-side polarizing plate 81 as in the bright spot defect blackening device 103 in the third embodiment, the driving state of the liquid crystal panel in a state where the polarizing plate on the laser incident surface side of the liquid crystal panel is peeled off. It is possible to perform blackening processing while observing.

1 color filter color material, 15 liquid crystal panel, 17 laser oscillator,
18 laser drive power supply, 31-33 laser generator, 40 external modulation element,
41 rotating plate, 45 drive source, 50 liquid crystal panel moving device, 60 bright spot defective pixel,
70 output modulator, 81 polarizing plate,
101-103 Bright spot defect blackening device.

Claims (2)

In the method of blackening a bright spot defect in which the color filter of the bright spot defective pixel of the liquid crystal panel is scanned by irradiating the laser beam from the laser oscillator relative to the black color filter of the bright spot defective pixel.
Using a semiconductor laser as the laser oscillator,
A period shorter than the time (D / V) determined by the laser beam spot diameter (D) and the laser beam scanning speed (V) on the color filter for the irradiation output of the laser beam irradiated to the color filter of the bright spot defective pixel Scan with modulation by modulating the drive current of the semiconductor laser with
A bright spot defect blackening method for a liquid crystal panel. 2. The method for blackening a bright spot defect in a liquid crystal panel according to claim 1, wherein the laser beam irradiation is performed in a state where a polarizing plate on a laser beam incident surface side of the liquid crystal panel is removed.

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