JP5163997B2 - Optical sensor - Google Patents

Description

  The present invention relates to an optical sensor for detecting an exposure lamp blink timing of an exposure apparatus, and more specifically, a flash lamp blink timing comprising at least two sensors arranged in parallel and having different reading speeds. The present invention relates to an optical sensor for detecting

For exposure devices such as color filters for liquid crystal substrates, a glass substrate surface coated with a resist is directly irradiated with exposure light and scanned on the glass substrate surface, and an exposure mask having an exposure pattern is provided. And the exposure pattern is transferred to the glass substrate surface.
The latter includes an exposure apparatus that performs exposure while moving the color filter and the exposure mask relatively in steps (hereinafter referred to as “step proximity exposure apparatus”), and the color filter and the exposure mask relatively. There is an exposure apparatus that performs exposure while moving continuously (hereinafter referred to as “continuous proximity exposure apparatus”).
In this continuous proximity exposure apparatus, there are those that use continuous light as exposure light and those that use flash light, and those that use continuous light are suitable for strip type color filter exposure apparatuses. Those using light are suitable for a staggered color filter exposure apparatus.
In the staggered color filter exposure apparatus (hereinafter referred to as “flash exposure apparatus”) using the flash light, the flash lamp blinks in accordance with a predetermined exposure position (a predetermined pixel position of the color filter). It is necessary to use a method of detecting one side of pixels arranged in a direction orthogonal to the color filter transport direction with a line sensor or photo sensor and turning on or off the flash lamp using the detection signal as a trigger ( Patent Document 1).
JP 2006-017895 A

However, since the line sensor reads signal charges for each line, when the line sensor and the object to be measured move relative to each other, the resolution for detecting the position of the sensor is affected by the reading speed of the signal charges. .
Therefore, the detection accuracy of the exposure start position or the exposure stop position (one side of the pixel in the color filter transport direction) detected by the line sensor is lowered, and the length of the line sensor (the length in which the light receiving elements are arranged in series) is reduced. As the length increases, the readout speed of one line becomes slower, and there is a problem that the timing of turning on / off the flash lamp cannot be accurately taken.

  On the other hand, the detection of the exposure start or stop position by one or more independent photosensors does not cause the problem of data acquisition time like the above line sensor, but by detecting foreign matter and scratches on the surface of the color filter. In some cases, the exposure start or stop position cannot be accurately detected.

  The present invention has been made in view of the above circumstances, and provides an optical sensor capable of accurately taking the flashing timing of the flash lamp in a continuous proximity exposure apparatus using an exposure flash lamp. It is an object.

The present invention is characterized by the following points in order to solve the above problems.
In other words, the optical sensor according to claim 1 is provided with a stage on which a substrate to be exposed is placed and continuously transported in a predetermined direction, and is disposed close to the upper side of the substrate, and the predetermined exposure pattern and the substrate an exposure mask having a detection window for detecting, through exposure pattern mask the exposure, in a continuous exposure apparatus with a flash lamp for irradiating the exposure light exposure target substrate, through the detection window An optical sensor for detecting an edge serving as a reference of the exposure target substrate, wherein a plurality of light receiving elements are arranged in a line on a line, and a first imaging means for reading out the charges of the light receiving elements for each line; An arrangement direction of the light receiving elements of the first image pickup means and a second image pickup means in which at least one or more independent light receiving elements are arranged on parallel axes spaced apart from each other are integrally provided. The interval is smaller than the width of the detection window in the transport direction of the substrate, and the image capturing period of the first imaging unit and the image capturing period of the second imaging unit are different. Yes.

  According to a second aspect of the present invention, there is provided an optical sensor comprising: a first imaging unit that arranges a plurality of light receiving elements in a line on a line, and reads the charge of the light receiving element for each line; and the light receiving element of the first imaging unit An optical sensor having a second imaging unit in which at least one or more independent light receiving elements are arranged on an axis parallel to the arrangement direction of the first imaging unit, wherein image capture by the second imaging unit is performed by its own clock signal. The image capturing of the first imaging means is performed by an external signal generated at a period longer than the period of the clock signal of the second imaging means.

The present invention has the following excellent effects.
That is, in the present invention, the color filter relatively moves the lower part of the imaging unit according to the present invention in a direction perpendicular to the line sensor, so that the second light receiving element firstly converts one side of the pixel to the color sensor. It detects accurately with respect to the filter transport direction (110, 111, 112 in FIG. 7B), and then has a predetermined length including one side of this pixel (in a direction parallel to the axis perpendicular to the color filter transport direction). (Length) is detected by the first light receiving element row (101, 102, 103 in FIG. 7C) of the line sensor, the second light receiving element erroneously detects dust or the like as one side of the pixel. However, the first light receiving element row of the line sensor does not detect the length of one side of the pixel, and the exposure start or stop position can be detected without error.

Further, since the gap between the light receiving element of the second image pickup means and the light receiving element row of the first image pickup means is determined in advance, the light receiving element of the second image pickup means is the pixel of the pixel as described later. The color filter transport including position data in the color filter transport direction when one side in the color filter transport direction is detected and one side of the pixel detected by the light receiving element array of the first imaging unit with a predetermined resolution. By comparing the position data in the direction, an error in lighting timing of the flash lamp can be prevented.
The light receiving element array of the first image pickup means of the line sensor includes one side of the pixel detected with a predetermined resolution based on the position data in the color filter transport direction detected by the light receiving element of the second image pickup means. By correcting the position data in the color filter transport direction, the lighting timing of the flash lamp can be correctly set based on the corrected output signal of the light receiving element array of the first imaging means.

Hereinafter, an optical sensor according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, FIG. 1 is a conceptual diagram showing an optical sensor 1 according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing an exposure apparatus 2 provided with the optical sensor 1.

  The optical sensor 1 is opposed to the color filter W, and includes a light receiving element array (hereinafter referred to as “line sensor”) 10 of a first imaging unit that detects pixels Wa by lines, and a second that detects pixels Wa by spots. The line sensor 10 includes a light-receiving element (hereinafter referred to as “photo sensor”) 11 serving as an imaging unit, and a transfer charge coupled device (hereinafter referred to as “CCD”) 100 that performs photoelectric conversion is arranged in a line. The photosensor 11 is composed of at least one or more photodiodes arranged at equal intervals on the axis (b) parallel to the arrangement axis (a) of the CCD 100.

The line sensor 10 includes a line sensor A / D converter 10a that performs A / D conversion on a signal from the line sensor 10, and a camera link that converts an output signal from the line sensor A / D converter 10a for transmission. An output control unit 10b is provided, and the camera link output control unit 10b is connected to the control unit 70 via a camera link input control unit 74 and an image processing unit 75 described later.
The camera link input control unit 74 is for returning the signal from the camera link output control unit 10 b to the original signal format and transmitting it to the image processing unit 75.
The image processing unit 75 binarizes the signal from the camera link input control unit 74 with a predetermined threshold value α2 set in advance and transmits the signal to the arithmetic processing unit 70.

Further, the camera link output control unit 10b receives a signal (a signal that synchronizes the conveyance of the stage 6 and the data acquisition of the line sensor 11) obtained by performing arithmetic processing on the signal from the stage counter 71 described later by the arithmetic processing unit 70, The line sensor 10 has a function of transmitting image data for one line of the CCD 100 to the line sensor A / D converter 10a.
That is, the image data for one line of the charge coupled device 100 is captured in synchronism with the stage counter 71 of the transport stage 6.

The photosensor 11 includes a photosensor A / D converter 11a that converts an analog output from the photosensor 11 into a digital output. The photosensor A / D converter 11a performs an operation through an image processing unit 72 described later. It is connected to the processing unit 70.
The output of the photosensor 11 is constantly monitored regardless of the operation of the transport stage 6, and image processing is performed via a photosensor A / D converter 11a by a signal of an internal clock (not shown) of the photosensor 11. It is sent to the unit 72.
The image processing unit 72 binarizes the signal from the photosensor A / D converter 11a with a predetermined threshold value α1 set in advance and transmits the signal to the arithmetic processing unit 70.
The binarization process is a process for obtaining an edge (hereinafter referred to as a “target edge”) of the pixel Wa of the color filter W, which becomes the lighting timing of the flash lamp 3 described later.

In the line sensor 10, the photosensor 11 detects the rising edge (hereinafter referred to as “up edge”) A1 or the falling edge (hereinafter referred to as “down edge”) A2 of the pixel Wa of the color filter W in FIG. Then, after a predetermined time T1 (a time obtained by dividing the previously measured distance L1 between the photosensor 11 and the line sensor 10 in the X-axis direction by the moving speed of the transfer stage 6 in the X-axis direction), Although the up edge a1 or the down edge a2 is detected, the line sensor 10 reads the charge for one line and then captures the next image. Therefore, in the device in which the color filter W continuously moves, The position of the up edge a1 or the down edge a2 exists in the area shown by C1 and C2 in FIG. Will do.
Further, when the predetermined time T1 is calculated, the output of the photosensor 11 is binarized by the image processing unit 72 with a preset threshold value α1, and the up edge A1 or the down edge A2 is detected. It is.
The rising edge means an edge at which the signal level of the light receiving element rises when shifting from the black matrix BL region to the pixel Wa portion, and the falling edge means from the pixel Wa portion to the black matrix BL region. This means an edge at which the signal level of the light receiving element falls during the transition (the same applies hereinafter).

  The exposure apparatus 2 mounts a color filter W to be exposed and transports it in the X direction, a stage position sensor 6a that detects the position of the transport stage 6 in the X direction, and above the exposure target W. An exposure mask 4 disposed on the optical mask 1, an optical sensor 1 disposed above the exposure mask 4, and an illumination device that is disposed below the transport stage 6 and emits illumination light from the back surface of the color filter W 5, the exposure flash lamp 3 disposed downstream of the color filter W in the transport direction (c) and above the exposure mask 4, these transport stage 6, stage position sensor 6 a, optical A control device 7 is provided for controlling the sensor 1 and the exposure flash lamp 3.

The transport stage 6 has stage drive means (not shown) (for example, composed of guide rails, ball screws and nuts, servo motors, etc.), and the color filter W is moved in the X-axis direction of FIG. 2 by this stage drive means. It is continuously conveyed at a predetermined speed in the direction of arrow C.
In this embodiment, the position of the color filter W in the X-axis direction in FIG. 2 is continuously detected by the stage position sensor 6a having a resolution of about 1 μm.
The X-axis direction position data signal of the color filter W from the stage position sensor 6 a is sent to the stage counter 71 of the control device 7.

As shown in FIG. 3, the color filter W includes a plurality of pixels Wa arranged in a matrix, and is red (hereinafter referred to as “R”), green (hereinafter referred to as “G”), or blue (hereinafter referred to as “G”). , “B”) is placed on the transfer stage 6 in a state where it is appropriately applied to the pixels Wa.
Then, the resist-coated portion is exposed with exposure light from an exposure flash lamp 3 described later that is irradiated through an exposure mask 4 described later.

As shown in FIG. 4, the exposure mask 4 includes an exposure pattern portion 4c and a detection window portion 4d provided on the light shielding film 4b applied on the transparent substrate 4a.
The detection window part 4d is a light transmission part from which the light shielding film 4b is removed, and the optical sensor 1 passes through the detection window part 4d and is in a direction perpendicular to the transport direction (X-axis direction) of the color filter W ( This is for detecting the up edge A1 (a1) or the down edge A2 (a2) of the pixel Wa in the Y-axis direction).
The exposure pattern portion 4c is a light transmission portion from which the light shielding film 4b is removed with a predetermined exposure pattern, and the resist portion is irradiated with exposure light from the flash lamp 3 through the exposure pattern portion 4c. It is for exposing a part.
The length of the exposure pattern portion 4c in the transport direction of the color filter W is equal to L0 of the exposure range of each pixel Wa.

The exposure mask 4 can be moved in the X-axis and Y-axis directions by a mask driving device (not shown), and can be rotated in the θ-axis direction.
Further, the side edge A3 (FIG. 6) of the pixel Wa in an arbitrary column of the pixels Wa arranged continuously in the X-axis direction of the color filter W is moved by the mask driving device by a predetermined CCD element 100 of the line sensor 10. The exposure mask 4 is continuously positioned in the Y-axis direction by the mask driving device with the side edge A3 as a reference.
Thus, the relative positional relationship between each CCD element 100 of the line sensor 10 and each pixel Wa arranged in the Y-axis direction of the color filter W is kept constant.

The exposure flash lamp 3 is controlled by a control device 7 to be described later, and can emit light in the ultraviolet region intermittently, with a predetermined interval in the X-axis direction from the optical sensor 1, The color filter W is arranged on the downstream side in the transport direction (c), and emits light according to a signal from the arithmetic processing unit 70 described later when the color filter W reaches a predetermined position below the exposure flash lamp 3. It is like that.
The exposure flash lamp 3 may be a laser oscillator that emits laser light in the ultraviolet region in addition to the ultraviolet discharge lamp.
The center of the XY plane of the exposure flash lamp 3 is arranged so as to coincide with the center of the XY plane of the exposure pattern portion 4 c of the exposure mask 4.

When the color filter W reaches the position immediately below the exposure flash lamp 3, the center of the pixel Wa (intermediate position between the up edge A1 and the down edge A2) of the exposure pattern portion 4c of the exposure mask 4 is used. It means when the center position in the X-axis direction has been reached.
That is, in the arithmetic processing unit 70 described later, the stage stage position (X1) when the line sensor 10 detects the up edge A1 of a predetermined pixel and the up edge A1 of the predetermined pixel Wa are detected, and then the predetermined processing is performed. The difference (ΔX1) between the stage position (X2) after the lapse of time is calculated, and this ΔX1 and the X of the exposure flash lamp 3 input to the arithmetic processing unit 70 using the external input means 9 in advance are calculated. The difference (ΔX2) between the axial center and the distance (L1 + L2 + L0 / 2) of the distance in the X-axis direction between the center (b) of the photosensor 11 and the L0 of the pixel Wa (L1 + L2 + L0 / 2) is calculated. , ΔX2 is substantially zero, it is determined that the color filter W has reached a predetermined position below the exposure flash lamp 3, and a flash run to be described later is sent from the arithmetic processing unit 70. A signal for lighting the exposure flash lamp 3 to the output control unit 76 is adapted to transmit.
The stage positions X1 and X2 are detected by the stage position sensor 6a while the stage 6 is continuously moving in the X-axis direction.

The control device 7 includes an arithmetic processing unit 70, a stage counter 71, image processing units 72 and 75, a synchronization signal output unit 73, a flash lamp output control unit 76, an illumination controller 5a, a screen display 8, and an external input unit 9. ing.
The stage counter 71, the image processing units 72 and 75, the synchronization signal output unit 73, the flash lamp output control unit 76, the illumination controller 5a, the screen display 8, and the external input means 9 are connected to the arithmetic processing unit 70, respectively. The counter 71 is connected to the stage position sensor 6a, and the image processing units 72 and 75 are connected to the photo sensor A / D converter 11a and the line sensor A / D converter 10a, respectively.
The synchronization signal output unit 73 is connected to the camera link output controller 10b, and is a signal obtained by performing arithmetic processing on the signal from the stage counter 71 by the arithmetic processing unit 70 (a signal for synchronizing the conveyance of the stage 6 and the data acquisition of the line sensor 11). ) To the camera link output controller 10b.

The flash lamp output control unit 76 is connected to the flash lamp 3 and receives a signal from the arithmetic processing unit 70 to control the lighting timing of the flash lamp 3.
The illumination controller 5a is connected to the illumination device 5 and is for adjusting the blinking of illumination light and the intensity of illumination light that are emitted from below to the pixels Wa of the color filter W.
The image display 8 is for displaying the output image of the line sensor 10 and the photo sensor 11 of the optical sensor 1, and the external input means 9 is previously measured by the photo sensor 11 and the line sensor 10. In addition to the distance L1 in the X-axis direction, the distance L2 between the X-axis direction center of the exposure flash lamp 3 and the center of the line sensor 10 in the X-axis direction, the threshold values α1 and α2, the operating conditions of the exposure apparatus 2, etc. Is input to the arithmetic processing unit 70 from the outside.

Next, the operation of the exposure apparatus 2 configured as described above will be described with reference to FIGS.
First, when the exposure apparatus 2 is turned on, the optical sensor 1, the illumination apparatus 5, and the control apparatus 7 shown in FIG. Next, when the color filter W is placed on the stage 6 and a start switch (not shown) is operated, the stage 6 transports the color filter W at a constant speed in the direction of arrow C (a direction parallel to the X axis). To do.
When the color filter W reaches the imaging position of the imaging means 1, exposure is performed according to the following steps.

First, in step S <b> 1, the pixels Wa are continuously imaged in synchronization with the internal clock signal of the photosensor 11 by the photodiode of the photosensor 11. The image (luminance information) 1 is transmitted to the image processing unit 72 via the photosensor A / D converter 11a. In the image processing unit 72, the image (image luminance information) 1 has a threshold value α1 as shown in FIG. Then, the data is binarized and transmitted from the image processing unit 72 to the arithmetic processing unit 70.
From the data binarized by the threshold α1, the up edge A1 and the down edge A2 are counted as one set by the stage counter 71, and the count number (N) is sent to the arithmetic processing unit 70 as needed.
The output of the stage position sensor 6a when the up edge A1 is detected is sent to the arithmetic processing unit 70.

  Next, in step S <b> 2, the pixel Wa is continuously imaged by the line sensor 10 in synchronization with the output of the stage counter 71 of the transport stage 6. The image (luminance information) 2 is transmitted to the image processing unit 75 via the line sensor A / D converter 11a and the camera link input control unit 74. In the image processing unit 75, the image (luminance information) 2 is As shown in FIG. 5, the binarization process is performed with the threshold value α <b> 2 and transmitted from the image processing unit 75 to the arithmetic processing unit 70.

Next, in step S3, the value of the stage position sensor 6a of the transport stage 6 when the up edge A1 and the down edge A2 are detected by the arithmetic processing unit 70 is set to the interval L1 between the line sensor 10 and the photo sensor 11. The value (LX) to which the position data corresponding to the minute is added is compared with the value of the stage position sensor 6a of the transfer stage 6 when the line sensor 10 detects the up edge a1 and the down edge a2, and is within a predetermined range. It is determined whether or not it is in (C1, C2).
The range of C1 and C2 differs depending on the arrangement length of the CCD element 100. In this embodiment, the arrangement length of the CCD element 100 is such that the range of C1 and C2 is within a range of several μm. I use it.

Next, in step S4, if the result of the determination is within a predetermined range, the calculation processing unit 70 determines whether or not the pixel Wa is an exposure target from the count acquisition count (N). For the pixel Wa to be exposed, the up edge A1 is used as the lighting timing of the flash lamp 3, and the transport stage 6 is at a distance (L1 + L2) from the position where the photosensor 11 detects the up edge A1. Is moved from the arithmetic processing unit 70 to the flash lamp output control unit 76, the flash lamp 3 is turned on, and the flash lamp 3 is not turned on for other non-exposure pixels Wa. Let it pass.
Note that, if the result of the determination is that it is not within the predetermined range (C1, C2), the up edge A1 is not adopted as the lighting timing of the flash lamp 3.
Then, when all the columns of pixels Wa to be exposed are exposed, the exposure operation of the pixels Wa of a predetermined color is finished.

The present invention prevents the detection of an erroneous target edge by the photosensor 11 by combining the photosensor 11 with a fast detection speed of the target edge and the line sensor 10 that detects the edge portion with a line and the detection speed is slow. In addition, the detection accuracy of the up edge a1 and the down edge a2 by the line sensor 10 is supplemented.
Accordingly, the photosensor 11 has the light receiving and transfer charge coupled devices 10a arranged in a line within a range where the detection speed of the target edge does not matter, and is shorter than the line sensor 10 and receives and transfers light. A device having a small number of charge coupled devices 10a may be used.

It is a conceptual diagram which shows embodiment of the optical sensor which concerns on this invention. It is explanatory drawing which shows embodiment of the proximity exposure apparatus using the said optical sensor. It is a conceptual diagram for description of a color filter. It is a conceptual diagram for description of an exposure mask. It is explanatory drawing about the detection output of the pixel edge by a photo sensor and a line sensor. It is explanatory drawing about the detection of the side edge of the pixel of a color filter by a line sensor. It is explanatory drawing of the up edge detection effect | action of the pixel by a photo sensor and a line sensor, (a) is a conceptual diagram which shows the relationship between the pixel of a color filter and an optical sensor, (b) is a photo sensor up of a pixel. It is a conceptual diagram which shows the image which detects an edge, (c) is a conceptual diagram which shows the image in which a line sensor detects the up edge of a pixel. It is a flowchart explaining operation | movement of the proximity exposure apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical sensor 2 Proximity exposure apparatus 3 Flash lamp 4 Exposure mask 5 Illumination apparatus 6 Conveyance stage 7 Control apparatus 8 Display apparatus 9 External input means 10 Line sensor 11 Photo sensor 70 Arithmetic processing part A1, a1 Up edge A2, a2 of a pixel Pixel down edge R, G, B Pixel color (R is red, G is green, B is blue)

Claims (2)

An exposure having a stage on which a substrate to be exposed is placed and continuously transported in a predetermined direction, and a detection window that is disposed in the vicinity of the substrate and detects a predetermined exposure pattern and the substrate. and use the mask, through the exposure pattern of the mask the exposure, in a continuous exposure apparatus with a flash lamp for irradiating the exposure light exposure target substrate, through the detection window, serving as a reference edge of the exposure target substrate An optical sensor for detecting,
A plurality of light receiving elements are arranged in a line on a line, and the first image pickup means for reading out the charges of the light receiving elements for each line, and the arrangement direction of the light receiving elements of the first image pickup means are parallel to each other with a space therebetween A second imaging means having at least one independent light receiving element disposed on the axis, and the interval is smaller than the width of the detection window in the transport direction of the object to be exposed;
An optical sensor characterized in that an image capturing period of the first imaging unit is different from an image capturing period of the second imaging unit. The image capturing of the second imaging unit is performed by its own clock signal, and the image capturing of the first imaging unit is generated with a period longer than the cycle of the own clock signal of the second imaging unit. 2. The optical sensor according to claim 1, wherein the optical sensor is performed by a signal.