JP6524658B2 - Exposure device - Google Patents

Description

  The present invention relates to a light beam exposure apparatus, an electronic device equipped with the light beam exposure apparatus, and an operation method of the light beam exposure apparatus.

  For example, a light beam exposure apparatus such as a substrate direct writing exposure apparatus which exposes an object such as a printed board with a light beam is known. In general, a light beam exposure apparatus includes a light source that generates a light beam modulated based on image data, and an optical system that deflects the generated light beam, and scans an object with the light beam to generate image data Write an image to the object. In recent years, there is a light beam exposure apparatus provided with an array of a plurality of laser light sources or LED light sources as light sources.

  When a plurality of scanning lines (lines) in the main scanning direction are respectively exposed by light beams from a plurality of light sources aligned in the sub scanning direction, they are exposed by these light beams due to errors in the optical system and manufacturing limitations. Accuracy of the exposure position may vary. As the adjacent light beams approach one another, the area between the exposure positions of these light beams is more heavily exposed and as they are further apart less light exposure. Therefore, in the image written to the object, the lines (vertical lines) in the sub-scanning direction may be jerky or the widths of the lines (horizontal lines) in the main scanning direction may be uneven. In other words, due to the deviation of each exposure position from the reference position on the object (for example, equally spaced positions along the sub-scanning direction on the object), the exposure area on the object (non-image data The contour shape of the portion corresponding to the area of the pixel having a luminance value of zero changes.

  According to the distance between the exposure positions and the continuity of the pixel values corresponding to the exposure areas extending in the sub-scanning direction, in order to suppress the change in the contour shape of the exposure area caused by the deviation of each exposure position. It is already known to change the exposure energy of each light beam to correct density unevenness.

  Patent Document 1 discloses a hardware technology without causing a significant increase in cost for the purpose of reducing unevenness in the amount of light generated due to positional fluctuations of a plurality of lines in the main scanning direction (that is, fluctuations in distance between lines). Correction of the light amount is disclosed.

  In the invention of Patent Document 1, although the light amounts of the respective pixels are corrected so as to reduce the light amount unevenness of the plurality of pixels continued in the sub scanning direction, the light amounts of the plurality of pixels continued in the main scanning direction are not correction targets. In the main scanning direction, only the presence or absence of the adjacent pixel of the pixel to be corrected is considered. Further, in the invention of Patent Document 1, the light quantities of a plurality of pixels which continue in an oblique direction (direction between the main scanning direction and the sub scanning direction) are not to be corrected. Further, in the invention of Patent Document 1, the case where each pixel has a pixel value (brightness value) of gradation of three or more is not considered. Therefore, even if the pixel value of each pixel of the image data is corrected according to the invention of Patent Document 1, it is not possible to sufficiently suppress the change in the contour shape of the exposure region caused by the deviation of each exposure position.

  An object of the present invention is caused by the deviation of each exposure position in the case of irradiating a plurality of exposure positions with a plurality of light beams and in the case where each pixel of image data has a luminance value of three or more gradations. An object of the present invention is to provide a light beam exposure apparatus capable of suppressing a change in the contour shape of an exposure area.

An exposure apparatus according to an aspect of the present invention is
An exposure apparatus that irradiates and writes each pixel of input image data with a plurality of light beams along the main scanning direction and the sub scanning direction on the exposure object,
An image processing circuit that corrects the luminance value of each pixel of the image data based on a predetermined setting ;
And generating a plurality of light beams respectively irradiating different exposure positions adjacent to each other along the sub scanning direction on the exposure object based on the corrected image data sent from the image processing circuit. And a light emitting device for scanning the light beam of
The image processing circuit
Each pixel each exposure position of the plurality of light beams, when included in the edge of the exposure area extending along the sub scanning direction, in accordance with the distance between the respective exposure positions, corresponding to the respective exposure positions Correct the brightness value of
Exposure position one light beam of the plurality of light beams, when included in the edge of the exposure area extending along the main scanning direction, wherein the exposure of the equidistant reference position of each exposure position It is characterized in that the luminance value of the pixel corresponding to the exposure position is corrected according to the position shift.

According to the optical beam exposure apparatus of the present invention, when irradiating a plurality of exposure positions by a plurality of light beams, it is possible to suppress a change in the contour shape of the exposure area due to the deviation of each exposure position.

It is a perspective view showing composition of light beam exposure device 20 concerning an embodiment of the present invention. It is a block diagram which shows the structure of the light beam exposure apparatus 20 of FIG. FIG. 9 is a top view showing the reference positions of first exemplary light beams A to D emitted from the light emitting device 23-1 of FIG. 2 to the printed wiring board 30. It is a top view which shows the actual exposure position of light beam AD of FIG. The exposure area of the printed wiring board 30 when the light beams A to D in FIG. 3 are scanned in the main scanning direction when the deformation of the outline of the exposure area due to the overlap between the exposure areas of the light beams adjacent to each other is not taken into consideration. FIG. In consideration of the deformation of the outline of the exposure area due to the overlap between the exposure areas of the light beams adjacent to each other, the exposure area of the printed wiring board 30 when the light beams A to D in FIG. FIG. If the deformation of the outline of the exposure area due to the overlap between the exposure areas of the light beams adjacent to each other is not taken into consideration, the exposure area of the printed wiring board 30 when the light beams A to D in FIG. FIG. Considering the deformation of the outline of the exposure area due to the overlap between the exposure areas of the light beams adjacent to each other, the exposure area of the printed wiring board 30 when the light beams A to D in FIG. FIG. FIG. 7 is a diagram showing an example of luminance values of respective pixels of image data corresponding to an exposure region extending in the sub scanning direction on the printed wiring board 30. It is a figure which shows the example of 1st correction | amendment of the luminance value of FIG. 5 is a table showing a first determination criterion for correcting the luminance value of each pixel of image data by the image processing circuit 21 of FIG. 2; It is a figure which shows the 2nd example of correction | amendment of the luminance value of FIG. A top view showing an exposure region of the printed wiring board 30 when scanning the second exemplary light beams A, B and C emitted from the light emitting device 23-1 of FIG. 2 to the printed wiring board 30 in the main scanning direction. It is. A top view showing the exposure region of the printed wiring board 30 when the third exemplary light beams C, D, and A emitted from the light emitting device 23-1 of FIG. 2 to the printed wiring board 30 are scanned in the main scanning direction. It is. FIG. 7 is a view showing an example of luminance values of respective pixels of image data corresponding to an exposure area extending in the main scanning direction on the printed wiring board 30. It is a figure which shows the example of 1st correction | amendment of the luminance value of FIG. 5 is a table showing a second determination criterion for correcting the luminance value of each pixel of the image data by the image processing circuit 21 of FIG. 2; It is a figure which shows the 2nd example of correction | amendment of the luminance value of FIG. FIG. 17 is a diagram showing a first correction example of luminance values of respective pixels of image data corresponding to portions of a pair of exposure regions extending in the sub scanning direction on the printed wiring board 30 and facing each other through non-exposure regions. . FIG. 17 is a diagram showing a second correction example of the luminance value of each pixel of the image data corresponding to the part of the pair of exposure regions extending in the sub scanning direction on the printed wiring board 30 and facing each other via the non-exposure region. . It is a figure which shows the example of the luminance value of each pixel of the image data corresponding to the part of a pair of exposure area which extends in a diagonal direction on the printed wiring board 30, and opposes via a non-exposure area. It is a figure which shows the 1st example of correction | amendment of the luminance value of FIG. It is a figure which shows the 2nd example of correction | amendment of the luminance value of FIG. It is a flowchart which shows the luminance value correction process performed by the image processing circuit 21 of FIG.

  Hereinafter, a light beam exposure apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing the configuration of a light beam exposure apparatus 20 according to an embodiment of the present invention. FIG. 1 shows an overview of a substrate direct writing exposure apparatus as an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the light beam exposure apparatus 20 of FIG. FIG. 2 also shows the flow of data in the light beam exposure apparatus 20.

  The light beam exposure apparatus 20 operates under the control of the host computer 10, and the host computer 10 sends image data, control data and the like to the light beam exposure apparatus 20. The light beam exposure apparatus 20 includes a table on which the printed wiring board 30, which is an exposure object, is disposed. The light beam exposure apparatus 20 has a main scanning direction (+ X direction in FIG. 1) and a sub scanning direction (+ Y direction in FIG. 1) on the printed wiring board 30.

  For example, a photosensitive member such as a resist is formed on the printed wiring board 30.

  The light beam exposure apparatus 20 generates a plurality of light beams based on image data including a plurality of pixels each having a luminance value of three or more gradations including a maximum luminance value and a minimum luminance value, and a plurality of light beams Scans the object to write an image of the image data onto the object. The image written on the object comprises at least one exposure area corresponding to the area of the pixel having a luminance value different from the minimum luminance value and at least one non-exposure area corresponding to the area of the pixel having the minimum luminance value. including.

  Although the case where the exposure target is the printed wiring board 30, the exposed region is the wiring (conductor region), and the non-exposed region is the region where the conductor is removed will be described below, the opposite may be made.

  The light beam exposure apparatus 20 includes an image processing circuit 21, a control circuit 22, at least one light emitting device 23-1 to 23-6, and a driving device 26.

  The image processing circuit 21 executes image processing on the image data sent from the host computer 10 in accordance with the control data sent from the host computer 10, and the processed image data is sent to the light emitting devices 23-1 to 23-6. Send to Here, the image processing includes, for example, correction of input image data in order to correct positional deviation and distortion of the printed wiring board 30, such as rotation processing and scaling processing. Control data includes information for performing this image processing. In particular, the image processing circuit 21 corrects the luminance value of each pixel of the image data sent from the host computer 10 by executing the luminance value correction process of FIG. The luminance values are sent to the light emitting devices 23-1 to 23-6. The image processing circuit 21 includes, for example, a microprocessor or an FPGA, and a program for image processing executed thereon. The image data corrected by the image processing circuit 21 is sent to the light emitting devices 23-1 to 23-6, converted into light beams, and irradiated onto the printed wiring board 30.

  The light emitting device 23-1 includes light emitting elements 24A to 24D and a deflection device 25. The light emitting device 23-1 generates a plurality of light beams A to D respectively irradiating different exposure positions adjacent to each other along the sub scanning direction on the printed wiring board 30, and performs main scanning of the plurality of light beams A to D Scan in the direction. Each of the light emitting elements 24A to 24D is, for example, a laser light source or an LED light source, and generates light beams A to D, respectively. The deflecting device 25 includes, for example, a lens and a polygon mirror, and scans the light beams A to D in the main scanning direction by the reflection of the rotating polygon mirror. The other light emitting devices 23-2 to 23-6 are also configured similarly to the light emitting device 23-1.

  The control circuit 22 moves the printed wiring board 30 in the -Y direction (reverse direction of the sub scanning direction) using the drive device 26 in accordance with the control data sent from the host computer 10.

  The light emitting devices 23-1 to 23-6 are provided above the table of the light beam exposure apparatus 20, and irradiate the light beams A to D to the printed wiring board 30 disposed on the table. Since there is a limit to the range irradiated by one light emitting device, the length in the main scanning direction of the printed wiring board 30 is divided, and the divided regions are respectively irradiated by separate light emitting devices. In the example of FIG. 1, the light beam exposure apparatus 20 includes six light emitting devices 23-1 to 23-6. When the entire length in the main scanning direction of the printed wiring board 30 is scanned in a predetermined range in the sub scanning direction (a range corresponding to the light beams A to D), control is performed to scan another range in the sub scanning direction. The circuit 22 uses the drive device 26 to move the printed wiring board 30 in the -Y direction. The light beam scans the entire printed wiring board 30 by alternately repeating the scanning in the main scanning direction and the movement in the sub scanning direction.

  FIG. 3 is a top view showing the reference positions of the first exemplary light beams A to D emitted from the light emitting device 23-1 of FIG. 2 to the printed wiring board 30. As shown in FIG. Since the light beam exposure apparatus 20 alternately repeats scanning in the main scanning direction and movement in the sub scanning direction, the exposure position of the light beam A is on the + Y side of the exposure position of the light beam D, and so on. The exposure positions D to D are repeated along the sub-scanning direction. Ideally, the exposure positions of the light beams A to D on the printed wiring board 30 should be at equally spaced positions (reference positions) along the sub-scanning direction on the printed wiring board 30. In the example of FIG. 3, the exposure positions of the light beams A to D each have a circular exposure area. In the present specification, the center of the circular exposure area is taken as the exposure position of each light beam. In order to prevent gaps in the exposure regions of the light beams A to D, as shown in FIG. 3, the exposure positions of the light beams A to D are determined such that the exposure regions of the light beams adjacent to each other overlap.

  FIG. 4 is a top view showing the actual exposure position of the light beams A to D in FIG. The exposure positions of the light beams A to D are not actually at regular intervals, and may deviate from the reference position of FIG. Here, the light beams B and C shift to the -Y side, and the distance between the exposure positions of the light beams A and B and the distance between the exposure positions of the light beams B and C become smaller. The distance between the exposure positions is large. Thereby, the contour shape of the exposure area on the printed wiring board 30 changes due to the deviation of each exposure position from the reference position on the printed wiring board 30. The image processing circuit 21 of FIG. 2 executes each of the luminance value correction processes of FIG. 24 to suppress the change in the contour shape of the exposure area caused by the deviation of each exposure position. Correct the luminance value of the pixel.

  FIG. 5 shows the printed wiring board 30 when the light beams A to D in FIG. 3 are scanned in the main scanning direction without considering the deformation of the outline of the exposure region due to the overlap between the exposure regions of the light beams adjacent to each other. It is a top view which shows the exposure area of. FIG. 6 shows the printed wiring board 30 when the light beams A to D in FIG. 3 are scanned in the main scanning direction, considering the deformation of the outline of the exposure region due to the overlap between the exposure regions of the light beams adjacent to each other. It is a top view which shows the exposure area of. 5 and 6 are portions (longitudinal lines) of the exposure region extending along the sub scanning direction, and nine scanning lines (light beams A, B, C, D, A, B, C, The portion including the D and A scanning lines is shown. Since the exposure area of each light beam is circular, as shown in FIG. 5, small rattling occurs at the + X side edge and the −X side edge of the exposure area. However, since the exposure position of each light beam is equally spaced along the sub-scanning direction, the rattling of the edge of the exposure area has a constant period. In addition, the exposure amount becomes larger in the overlapping portion between the exposure regions of the light beams adjacent to each other, and the + X side edge and the −X side edge of the portion expand toward the non-exposure region, so The attached part is actually smooth as shown in FIG.

  FIG. 7 shows the printed wiring board 30 when the light beams A to D in FIG. 4 are scanned in the main scanning direction without considering the deformation of the outline of the exposure region due to the overlap between the exposure regions of the light beams adjacent to each other. It is a top view which shows the exposure area of. FIG. 8 shows the printed wiring board 30 when the light beams A to D in FIG. 4 are scanned in the main scanning direction, considering the deformation of the outline of the exposure region due to the overlap between the exposure regions of the light beams adjacent to each other. It is a top view which shows the exposure area of. FIGS. 7 and 8 are also portions (longitudinal lines) of the exposure region extending along the sub scanning direction, and nine scanning lines (light beams A, B, C, D, A, B, C). (D, A, scan lines) are shown. In the exposure region of FIG. 7, as described with reference to FIG. 4, the distance between the exposure positions of the light beams A and B and the distance between the exposure positions of the light beams B and C are small. The rattling is reduced at the + X side edge and the −X side edge of the exposure area of the beam. On the other hand, in the exposure region of FIG. 7, as described with reference to FIG. 4, since the distance between the exposure positions of the light beams C and D is large, + X side edge and −X side of the exposure region of these light beams At the edge, rattle increases. Overall, in the exposure region of FIG. 7, the rattling of the + X side edge and the −X side edge becomes larger than that of the exposure region of FIG. 5. Furthermore, in a portion where the distance between the exposure positions is small (a portion between the exposure positions of the light beams A and B, a portion between the exposure positions of the light beams B and C), the overlapping range of the exposure regions becomes large. The amount of exposure at As a result, the + X side edge and the −X side edge of the portion expand more toward the non-exposure region, and therefore, as shown in FIG. The difference of the exposure amount with the portion between the exposure positions further increases, and the rattling becomes more noticeable.

  Hereinafter, in the case where each pixel of the image data has a luminance value of three or more gradations, the image processing circuit 21 is configured to suppress the change in the contour shape of the exposure area caused by the deviation of each exposure position. A method of correcting the luminance value of each pixel corresponding to the exposure position will be described.

  If each pixel of the image data has a luminance value with three or more gray levels, for example, the pixels at the edge of the image, in particular at the oblique edge, are often set to a luminance value between the maximum luminance value and the minimum luminance value. Here, when the maximum luminance value is “4” and the minimum luminance value is “0” (ie, not exposed), the luminance value of the pixel of the oblique edge is “1”, “2”, “3”, or It is set to "4". This is a commonly used method for drawing an edge with less blurring and smooth.

  When each pixel of the image data has a luminance value of three or more gradations, in order to smooth the edge of the exposure area, it is necessary to determine the changed luminance value according to the original luminance value. When the light beam exposure apparatus 20 corrects the luminance value of each pixel corresponding to each exposure position so as to suppress the change in the contour shape of the exposure area caused by the deviation of each exposure position, the light beam exposure apparatus 20 responds to the original luminance value. Since the changed luminance value is determined, the edge of the exposure area can be smoothed.

Further, when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, it is not possible to set a luminance value exceeding the maximum luminance value, so the luminance value after the change of the pixel smoothes the edge of the exposure area. It is less than the luminance value considered to be necessary to Here, when the exposure position corresponding to the pixel to be corrected is at the edge of the exposure area, the exposure position corresponding to the adjacent pixel to the pixel to be corrected is in the non-exposure area. Therefore, this adjacent pixel has the minimum luminance value. Have. Therefore, when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and when the adjacent pixel of the pixel to be corrected has the minimum luminance value, instead of the luminance value of the pixel to be corrected, or The luminance value of the adjacent pixel of the pixel to be corrected is increased in addition to the luminance value of the pixel of. Thus, even when the luminance value of the pixel to be corrected exceeds the maximum luminance value due to the correction, the edge of the exposure area can be made smooth.

  When the printed wiring board 30 is exposed, the minimum value (threshold value) of the distance between the wirings (conductor areas) on the printed wiring board 30 is determined in advance. Here, when the exposure position corresponding to the pixel to be corrected is at the edge of the exposure area (for example, wiring), the exposure position corresponding to the adjacent pixel to the pixel to be corrected is in the non-exposure area (for example, the area between the wirings) Therefore, this neighboring pixel has a minimum luminance value. As described above, when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and the adjacent pixel of the pixel to be corrected has the minimum luminance value, the luminance value of the adjacent pixel of the pixel to be corrected is When the area is increased, the exposed area is expanded and the non-exposed area is narrowed. Therefore, by increasing the luminance value of the adjacent pixel of the pixel to be corrected, the distance between the wires may be less than a predetermined minimum value. For this reason, before increasing the luminance value of the pixel having the minimum luminance value, it is determined whether the distance between the wirings becomes equal to or more than the predetermined minimum value even if the luminance value of the pixel is increased.

  First, with reference to FIGS. 9 to 12, the case of suppressing the change in the contour shape of the exposure region extending in the sub scanning direction on the printed wiring board 30 will be described.

FIG. 9 is a view showing an example of the luminance value of each pixel of the image data corresponding to the exposure region extending in the sub scanning direction on the printed wiring board 30. As shown in FIG. 9 and others indicate the relationship between each pixel of the image data and the corresponding position on the printed wiring board 30, the main scanning direction (+ X direction in FIG. 1) and the sub scanning direction (FIG. 1) on the printed wiring board 30. 2 shows XY coordinates corresponding to (+ Y direction of 1). In the present embodiment, each pixel of the image data has luminance values “0” to “4” of five gradations. Normally, luminance values “0” to “3” are used, and when the exposure amount is further increased, a luminance value “4” is used. On the printed wiring board 30, a portion corresponding to a pixel region having a luminance value different from the luminance value "0" is an exposure region, and a portion corresponding to a pixel region having a luminance value "0" is a non- exposure region It is.

  FIG. 10 is a diagram showing a first correction example of the luminance value of FIG. The image processing circuit 21 determines the contour shape of the exposure area caused by the deviation of each exposure position based on the exposure position information indicating the deviation of each exposure position from the reference positions at regular intervals along the sub scanning direction on the object. The luminance value of each pixel corresponding to each exposure position is corrected so as to suppress the change of. In the image data of FIG. 9, when the exposure positions of the light beams A to D are equally spaced as shown in FIG. 3, the image processing circuit 21 maintains the luminance value of each pixel without changing it. However, when the exposure positions of the light beams A to D are not equally spaced as shown in FIG. 4, the image processing circuit 21 changes the luminance value of the pixel corresponding to the edge of the exposure area as shown in FIG. Do. In FIG. 10 and others, the numbers enclosed by solid lines indicate portions where the luminance value is changed. The change of the luminance value needs to be performed at the pixel corresponding to the edge of the exposure area. When the pixel to be corrected has a luminance value different from the minimum luminance value “0”, and the adjacent pixel on the + X side or −X side of the pixel has the minimum luminance value “0”, the image processing circuit 21 corrects It is determined that the target pixel corresponds to the edge of the exposure area. Next, the image processing circuit 21 determines a new luminance value of the pixel to be corrected based on the current luminance value of the pixel to be corrected and the exposure position information. The exposure position information is, for example, the ratio of the distance between the exposure positions, that is, the ratio of the distance from the exposure position corresponding to the pixel to be corrected to the exposure position on the + Y side or the −Y side. The new luminance value of the pixel to be corrected is determined, for example, by referring to a table (FIG. 11) in which the ratio of the distance between the exposure positions is associated with the increase / decrease amount of the luminance value.

  Here, the ratio of distances between exposure positions is obtained, for example, as follows. When the light emitting devices 23-1 to 23-6 are attached to the light beam exposure apparatus 20, the glass surface for calibration is irradiated with the light beam, and the exposure position of the light beam and the shape of the exposure area are calibrated using a camera. Photographing, and based on the photographed image, the distance between exposure positions is determined. The ratio of distances between the exposure positions is calculated as “1” in an ideal case where the plurality of exposure positions are equidistant. The ratio of the distances between the exposure positions is input to the image processing circuit 21 as a part of control data.

  FIG. 11 is a table showing a first determination criterion for correcting the luminance value of each pixel of the image data by the image processing circuit 21 of FIG. The image processing circuit 21 reduces the luminance value of the pixel corresponding to at least one of the two exposure positions when the distance between the two adjacent exposure positions is shorter than the distance between the two adjacent reference positions. , Correct the luminance value of each pixel. The image processing circuit 21 increases the luminance value of the pixel corresponding to at least one of the two exposure positions when the distance between the two exposure positions adjacent to each other is longer than the distance between the two reference positions adjacent to each other. , Correct the luminance value of each pixel.

  FIG. 12 is a diagram showing a second correction example of the luminance value of FIG. When the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, the image processing circuit 21 may use the maximum luminance value as the luminance value after change. Further, the image processing circuit 21 increases the luminance value of the adjacent pixel when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction and when the adjacent pixel of the pixel to be corrected has the minimum luminance value. May be FIG. 12 shows a case where the distance between the exposure positions of the light beams C and D is larger than in the case of FIG. 10, and “2” is added to the luminance value of the pixel to be corrected according to the table of FIG. If the original luminance value of the pixel to be corrected is “3”, “2” is added to be “5”, which exceeds the maximum luminance value “4”. In this case, the luminance value of the pixel to be corrected is rounded to “4”, and the remaining increment “1” is added to the pixel of the adjacent pixel having the luminance value “0”.

  Thus, when the exposure region includes a portion extending along the sub-scanning direction, the image processing circuit 21 determines the width of the portion extending along the sub-scanning direction of the exposure region resulting from the shift of each exposure position. The luminance value of each pixel corresponding to each exposure position can be corrected so as to suppress the change of. By changing the luminance value of each pixel according to the distance between the exposure positions, it is possible to suppress rattling when a vertical line is drawn on the printed wiring board 30.

  Next, with reference to FIGS. 13 to 18, the case of suppressing the change in the contour shape of the exposure region extending in the main scanning direction on the printed wiring board 30 will be described.

  FIG. 13 is an exposure area of the printed wiring board 30 when the second exemplary light beams A, B, and C emitted from the light emitting device 23-1 of FIG. 2 to the printed wiring board 30 are scanned in the main scanning direction. Is a top view showing FIG. FIG. 14 is an exposure area of the printed wiring board 30 when the third exemplary light beams C, D, and A emitted from the light emitting device 23-1 of FIG. 2 to the printed wiring board 30 are scanned in the main scanning direction. Is a top view showing FIG. FIG. 13 shows a portion (horizontal line) of the exposure area extending along the main scanning direction and including three scanning lines (scanning lines of the light beams A, B, and C). FIG. 14 shows a portion (horizontal line) of the exposure region extending along the main scanning direction and including three scanning lines (scanning lines of the light beams C, D, and A). If there is variation in the distance between the exposure positions as shown in FIG. 4, for example, in the case of drawing a horizontal line having a width of 3 pixels, the case of drawing with light beams A, B and C, and light beams C, D and A In the case of drawing with, the width of the horizontal line will be different. In other words, the width of the horizontal line differs depending on the position in the sub scanning direction. As can be seen from FIGS. 13 and 14, the widths (lengths in the Y direction) are clearly different.

  FIG. 15 is a diagram showing an example of the luminance value of each pixel of the image data corresponding to the exposure region extending in the main scanning direction on the printed wiring board 30. As shown in FIG. FIG. 15 shows the case where the exposure area of the light beam C is the + Y side edge of the horizontal line as shown in FIG.

  FIG. 16 is a diagram showing a first correction example of the luminance value of FIG. The image processing circuit 21 determines the contour shape of the exposure area caused by the deviation of each exposure position based on the exposure position information indicating the deviation of each exposure position from the reference positions at regular intervals along the sub scanning direction on the object. The luminance value of each pixel corresponding to each exposure position is corrected so as to suppress the change of. When the pixel to be corrected has a luminance value different from the minimum luminance value “0”, and the adjacent pixel on the + Y side or −Y side of the pixel has the minimum luminance value “0”, the image processing circuit 21 corrects It is determined that the target pixel is an edge. When the exposure region of the light beam C is on the + Y side edge of the horizontal line as shown in FIG. 13, the width of the horizontal line is reduced because the exposure position of the light beam C is shifted to the -Y side. Therefore, it is necessary to change the luminance value of the pixel corresponding to the light beam C. Next, the image processing circuit 21 determines a new luminance value of the pixel to be corrected based on the current luminance value of the pixel to be corrected and the exposure position information. The exposure position information is, for example, the distance of the exposure position from the reference position. The image processing circuit 21 increases the luminance value, for example, as shown in FIG. In the example of FIG. 16, “1” is added to the luminance value of the pixel corresponding to the light beam C. For this change of the luminance value, there is a method of obtaining the increase / decrease value of the luminance value by table conversion from the distance from the ideal position of the light beam position, for example. For the new luminance value of the pixel to be corrected, for example, refer to a table (FIG. 17) in which the distance of the exposure position from the reference position is associated with the increase / decrease amount of the luminance value at the + Y side and −Y side edge. Determined by

  Here, the distance of the exposure position from the reference position is obtained, for example, as follows. When the light emitting devices 23-1 to 23-6 are attached to the light beam exposure apparatus 20, the glass surface for calibration is irradiated with the light beam, and the exposure position of the light beam and the shape of the exposure area are calibrated using a camera. Photographing and based on the photographed image, the distance of the exposure position from the reference position is obtained. The distance of the exposure position from the reference position is calculated with the distance between the ideal exposure positions as “1”. The distance of the exposure position from the reference position is input to the image processing circuit 21 as a part of control data.

  FIG. 17 is a table showing a second determination criterion for correcting the luminance value of each pixel of the image data by the image processing circuit 21 of FIG. The distance of the exposure position from the reference position is positive on the + Y side and negative on the −Y side. The plurality of exposure positions adjacent to each other along the sub-scanning direction are first and second exposure positions adjacent to each other, and the first exposure position corresponding to a pixel having a luminance value different from the minimum luminance value. And a second exposure position corresponding to the pixel having the minimum luminance value. The image processing circuit 21 decreases the luminance value of the pixel corresponding to the first exposure position when the first exposure position is shifted from the reference position of the first exposure position toward the second exposure position. . In other words, the image processing circuit 21 reduces the luminance value of the pixel corresponding to the edge of the exposure area when the exposure area extends toward the non-exposure area. When the first exposure position is shifted from the reference position of the first exposure position toward the second exposure position, the luminance value of the pixel corresponding to the first exposure position is decreased. When the first exposure position is shifted from the reference position of the first exposure position in the direction opposite to the second exposure position, the image processing circuit 21 calculates the luminance value of the pixel corresponding to the first exposure position. Increase In other words, the image processing circuit 21 increases the luminance value of the pixel corresponding to the edge of the exposure area when the exposure area is reduced (when the non-exposure area extends toward the exposure area). The image processing circuit 21 corrects the luminance value of each pixel as described above.

  FIG. 18 is a view showing a second correction example of the luminance value of FIG. As described above, when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, the image processing circuit 21 may use the maximum luminance value as the luminance value after change. Further, the image processing circuit 21 increases the luminance value of the adjacent pixel when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction and when the adjacent pixel of the pixel to be corrected has the minimum luminance value. May be In FIG. 18, the exposure position of the light beam C is shifted to the −Y side as compared with the case of FIG. 16, and the distance of the exposure position from the reference position of the light beam C is further increased. The case where it is going to add "2" to the luminance value of a pixel is shown. If the original luminance value of the pixel to be corrected is “3”, “2” is added to be “5”, which exceeds the maximum luminance value “4”. In this case, the luminance value of the pixel to be corrected is rounded to “4”, and the remaining increment “1” is added to the pixel of the adjacent pixel having the luminance value “0”.

  The examples of FIGS. 16 and 18 show the case where the exposure position of the light beam corresponding to the + Y side edge of the exposure area extending in the main scanning direction is shifted from the reference position to the −Y side. In this case, the luminance value of the pixel to be corrected may be reduced.

  The same applies to the -Y side edge of the exposure region extending in the main scanning direction. The luminance value of the pixel to be corrected is increased or decreased according to the deviation of the exposure position of the light beam.

  Thus, when the exposure region includes a portion extending along the main scanning direction, the image processing circuit 21 determines the width of the portion extending along the main scanning direction of the exposure region caused by the deviation of each exposure position. The luminance value of each pixel corresponding to each exposure position can be corrected so as to suppress the change of. By changing the luminance value of each pixel according to the distance of the exposure position from the reference position, it is possible to suppress the fluctuation of the width when the horizontal line is drawn on the printed wiring board 30.

  In the above, the case of suppressing the change in the contour shape of the exposure region extending in the main scanning direction or the sub scanning direction on printed wiring board 30 has been described. The case of considering the predetermined minimum value will be described.

  In the light beam exposure apparatus 20, the minimum value of the distance between the wirings on the printed wiring board 30 is defined. For example, if the minimum value of the distance between wires is 25 μm and the distance between exposure positions of light beams is 5 μm, a distance of at least 5 pixels between wires is required. In practice, the diameter of the exposure area of one light beam may be 5 μm or more, and therefore, a distance of 6 or 7 pixels may be required between the interconnections.

  Here, for example, as shown in FIG. 12, when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and when the adjacent pixel of the pixel to be corrected has the minimum luminance value, the pixel adjacent to the pixel to be corrected When the luminance value of the pixel is increased, the exposed area is expanded and the non-exposed area is narrowed. Therefore, by increasing the luminance value of the adjacent pixel of the pixel to be corrected, the distance between the wires may be less than a predetermined minimum value. Below, the case where priority is given to defining the distance between wires rather than suppressing the change in the contour shape of the exposure region caused by the displacement of each exposure position will be described.

  FIG. 19 shows a first correction example of the luminance value of each pixel of image data corresponding to the portion of a pair of exposure regions extending in the sub scanning direction on the printed wiring board 30 and facing each other through the non-exposure region. FIG. FIG. 20 shows a second correction example of the luminance value of each pixel of the image data corresponding to the portion of the pair of exposure regions extending in the sub scanning direction on the printed wiring board 30 and facing each other through the non-exposure region. FIG. The image written on the printed wiring board 30 includes at least a pair of opposing portions, each including a portion of the pair of exposure regions facing each other through the non-exposure region. FIG. 19 shows an example in the case where another exposure area exists via the non-exposure area for six pixels on the −X side of the exposure area of FIG. According to FIG. 19, the image processing circuit 21 changes the luminance value of the pixel corresponding to the edge of the exposure area extending in the sub scanning direction from "3" to "2" or "4", and further, the luminance value. The luminance value of the adjacent pixel of the pixel changed to “4” is changed from “0” to “1”. However, by changing the luminance value of the adjacent pixel of the pixel to be corrected from "0" to "1", the exposed area is expanded and the non-exposed area is narrowed. Therefore, the distance between wires can be less than 25 μm. There is sex. In this case, the luminance value of the pixel corresponding to the exposure position of the end on the -X side or + X side of the non-exposure area is not changed from the minimum luminance value in order to make the distance between the wires equal to or more than the predetermined minimum value. Let's do it. FIG. 20 shows such an example, and when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and when the adjacent pixel of the pixel to be corrected has the minimum luminance value, −X side of the non-exposure region The luminance value of the adjacent pixel of the pixel is maintained unchanged from the minimum luminance value “0”.

  Depending on the design of the light emitting devices 23-1 to 23-6, the direction in which the light beam is scanned in the main scanning direction is different (+ X direction or -X direction). The luminance value of the adjacent pixel on the + X side of the non-exposure area may be maintained at the minimum luminance value “0” according to the difference between the rising exposure characteristic and the falling exposure characteristic of the light beam, etc. The luminance value of the adjacent pixel of may be maintained at the minimum luminance value “0”.

  Similarly, for the portions of a pair of exposure regions extending in the main scanning direction on the printed wiring board 30 and facing each other via the non-exposure region, the change in the contour shape of the exposure region due to the deviation of each exposure position is It is possible to prioritize the definition of the distance between the wires rather than the suppression. For this reason, the luminance value of the pixel corresponding to the exposure position of at least one end of the −Y side and the + Y side of the non-exposure area is not changed from the minimum luminance value.

  Furthermore, not only in the main scanning direction and the sub scanning direction, but also in a pair of exposure regions extending in the other direction and facing each other via the non-exposure region, the contours of the exposure regions resulting from the deviation of each exposure position It is possible to prioritize the definition of the distance between wires rather than suppressing the change in shape.

  FIG. 21 is a diagram showing an example of the luminance value of each pixel of the image data corresponding to the portion of the pair of exposure regions extending in the oblique direction on the printed wiring board 30 and facing each other through the non-exposure region. Between the exposure areas extending in the oblique direction, there is a distance of 8 pixels in the main scanning direction and a distance of 8 pixels in the sub scanning direction. In this case, in both the main scanning direction and the sub scanning direction, there is a distance of 8 pixels between the exposure regions, which exceeds a predetermined minimum value (5 pixels) of the distance between the interconnections. Here, the distance L between the exposure regions in the oblique direction is L ≒ 5.66 from the Pythagorean theorem (L × L + L × L = 8 × 8). Therefore, even in the oblique direction, the distance between the exposure regions exceeds the predetermined minimum value (five pixels) of the distance between the interconnections.

  FIG. 22 is a diagram showing a first correction example of the luminance value of FIG. FIG. 22 shows an example of correction when the exposure positions of the light beam are not equally spaced as shown in FIG. In the example of FIG. 22, since both the correction in the sub scanning direction (FIGS. 9 to 12) and the correction in the main scanning direction (FIGS. 15 to 18) are performed, the pixels a1 and a2 surrounded by solid lines overlap. And the luminance value is changed from "0" to "2". In this case, in the main scanning direction and the sub scanning direction, there is a distance of 6 pixels between the exposure regions, which exceeds the predetermined minimum value (5 pixels) of the distance between the interconnections. However, in the oblique direction, pixels a3 and a4 of a luminance value "4" exist at positions of four pixels in the + X direction and four pixels in the + Y direction from the pixels a1 and a2. The distance L 'between these pixels is L' .apprxeq. 4.95 from the Pythagorean theorem (L'.times.L '+ L'.times.L' = 7.times.7). Therefore, in the oblique direction, the distance between the exposure areas is less than the predetermined minimum value (5 pixels) of the distance between the wires, and the definition can not be satisfied slightly.

FIG. 23 is a view showing a second correction example of the luminance value of FIG. The luminance value "2" of the pixels a1 and a2 is maintained without being changed from the original luminance value "0", or is changed to the luminance value "1". When maintaining without changing from the luminance value “0”, the improvement of the unevenness of the density is smaller than when changing the luminance value, but the distance between the wirings can be made equal to or more than the predetermined minimum value. On the other hand, even if it is changed to the luminance value "1", the above-mentioned distance L '= 4.95 is the calculation result in the case where the luminance value is large, and the exposure value is small at the luminance value "1". It is considered that L ′ = 5 or more, and the distance between the interconnections can be substantially made equal to or more than a predetermined minimum value.

  According to FIGS. 21 to 23, the image processing circuit 21 can make the distance between the wires equal to or larger than a predetermined minimum value as follows. The image written to the object includes at least one pair of opposing portions, each including portions of the pair of exposed regions opposing through the non-exposure region. In each pair of facing portions, the first distance in the main scanning direction, the second distance in the sub scanning direction, and the third in the direction between the main scanning direction and the sub scanning direction between the pair of facing portions. And distance. The image processing circuit 21 increases the luminance value of the adjacent pixel when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and when the adjacent pixel of the pixel to be corrected has the minimum luminance value. Even when the first, second and third distances all exceed a predetermined threshold value, the luminance value of the adjacent pixel is increased.

FIG. 24 is a flowchart showing the luminance value correction process performed by the image processing circuit 21 of FIG. FIG. 24 shows an example of the outline of the series of processes described above. In step S1, the image processing circuit 21 reads a pixel to be corrected. In step S2, the image processing circuit 21 determines whether the pixel is on the + X side or the −X side edge. If YES, the process proceeds to step S3, and if NO, the process proceeds to step S8. In step S3, the image processing circuit 21 changes the luminance value of the pixel in accordance with the distance between the exposure positions. In step S4, the image processing circuit 21 determines whether or not the changed luminance value has reached the luminance value considered to be necessary for suppressing the change in the contour shape of the exposure area, and when YES The process proceeds to step S8, and when NO, the process proceeds to step S5. In step S5, the image processing circuit 21 determines whether the distance to another exposure area on the + X side or the −X side is equal to or greater than a predetermined minimum value (threshold value) , and in the case of YES The process proceeds to step S6, and when NO, the process proceeds to step S8. In step S6, the image processing circuit 21 determines whether the distance to the other exposure area in the oblique direction is equal to or greater than a predetermined minimum value . If YES, the process proceeds to step S7, and if NO The process proceeds to step S8. In step S7, the image processing circuit 21 changes the luminance value of the adjacent pixel on the + X side or the −X side.

In step S8, the image processing circuit 21 determines whether the pixel is on the + Y side or the −Y side edge. If YES, the process proceeds to step S9, and if NO, the process proceeds to step S14. In step S9, the image processing circuit 21 changes the luminance value of the pixel in accordance with the deviation of the exposure position from the reference position. In step S10, the image processing circuit 21 determines whether or not the changed luminance value has reached the luminance value considered to be necessary for suppressing the change in the contour shape of the exposure area, and when YES The process proceeds to step S14, and when NO, the process proceeds to step S11. In step S11, the image processing circuit 21 determines whether the distance to another exposure area on the + Y side or the −Y side is equal to or greater than a predetermined minimum value , and in the case of YES proceeds to step S12. If NO, the process proceeds to step S14. In step S12, the image processing circuit 21 determines whether the distance to another exposure area in the oblique direction is equal to or greater than a predetermined minimum value . If YES, the process proceeds to step S13, and if NO The process proceeds to step S14. In step S13, the image processing circuit 21 changes the luminance value of the adjacent pixel on the + Y side or the −Y side. In step S14, the image processing circuit 21 reads the next pixel to be corrected.

  When the plurality of exposure positions in the sub-scanning direction are not equally spaced, the image processing circuit 21 sets luminance values of a plurality of pixels adjacent to each other corresponding to the exposure region extending in the main scanning direction, the sub scanning direction, or the oblique direction. To change the luminance value of the pixel corresponding to the edge of the exposure area and its vicinity. This makes it possible to improve the rattling of the vertical lines and the non-uniformity of the horizontal line width while making the distance between the wires equal to or more than the predetermined minimum value.

  According to the light beam exposure apparatus 20 of the present embodiment, in the case of irradiating a plurality of exposure positions with a plurality of light beams, and in the case where each pixel of image data has a luminance value of three or more gradations, It is possible to suppress the change in the contour shape of the exposure area caused by the deviation of the exposure position. In particular, the light beam exposure apparatus 20 can correct the luminance value of each pixel, reduce density unevenness, and suppress rattling of the vertical lines and non-uniformity of the horizontal line width. In addition, the light beam exposure apparatus 20 can correct the luminance values of a plurality of pixels which are continuous in an arbitrary direction of the main scanning direction, the sub scanning direction, and the oblique direction. In addition, the light beam exposure apparatus 20 can make the distance between the wires equal to or more than a predetermined minimum value in any direction of the main scanning direction, the sub scanning direction, and the oblique direction.

  Further, the light beam exposure apparatus 20 detects the luminance of the pixel to be corrected according to the deviation of each exposure position, the luminance value of the pixel to be corrected, and the luminance value of the adjacent pixel in the main scanning direction or the sub scanning direction. Correct the value. As a result, without losing the smoothness of the edge of the exposure area and maintaining the distance between the interconnections at a predetermined minimum value or more, the rattling of the vertical lines and the nonuniformity of the horizontal line width are suppressed. be able to.

  Also, the operation of the flowchart in FIG. 24 may be configured as a computer program executed on a computer. Thus, the functions can be realized by a computer having a CPU, a memory, and the like, so that porting and expansion of the functions becomes easy. Further, by storing the computer program in a computer readable recording medium, the program can be distributed as a single unit in addition to being incorporated in the device, and the version can be easily upgraded.

  In the embodiment described above, the light beam exposure device 20 for the printed wiring board 30 has been described, but the invention is not limited thereto, and electronic devices such as a printer, a copier, a multifunction device, and any other image forming device It may be. The electronic apparatus includes a light beam exposure apparatus 20, an input device for acquiring image data, and a drive device for moving an object. In this case, the object to be exposed (written) by the scanning of the light beam corresponds to, for example, a photosensitive drum whose position moves relative to the light beam exposure device 20.

  Although the drive device 26 is shown as a roller in FIG. 1, the drive device 26 may move the printed wiring board 30 by any method without being limited to the roller.

  Further, the present invention is not limited to the above embodiment. That is, those skilled in the art can carry out various modifications without departing from the gist of the present invention in accordance with conventionally known findings. Of course, as long as the configuration of the light beam exposure apparatus and the image forming apparatus of the present invention is provided even by such a modification, it is of course included in the scope of the present invention.

  A light beam exposure apparatus according to an aspect of the present invention, an electronic device equipped with the light beam exposure apparatus, and an operation method of the light beam exposure apparatus are characterized by having the following configuration.

A light beam exposure apparatus according to a first aspect of the present invention is
A plurality of light beams are generated based on image data including a plurality of pixels each having a luminance value of three or more gradations including the maximum luminance value and the minimum luminance value, and the object is scanned by the plurality of light beams. A light beam exposure apparatus for writing an image of the image data onto the object;
The image written to the object has at least one exposure region corresponding to a region of a pixel having a luminance value different from the minimum luminance value and at least one non-exposure region corresponding to a region of a pixel having the minimum luminance value. Including an exposure area,
The light beam exposure apparatus has a main scanning direction and a sub scanning direction on the object,
The above light beam exposure apparatus
A light emitting device for generating a plurality of light beams respectively irradiating different exposure positions adjacent to each other along the sub scanning direction on the object, and scanning the plurality of light beams in the main scanning direction;
An image processing circuit that corrects the luminance value of each pixel of the image data and sends it to the light emitting device;
The above image processing circuit
The contour shape of the exposure area due to the deviation of each exposure position based on the exposure position information indicating the deviation of each exposure position from the reference position at regular intervals along the sub scanning direction on the object Correcting the luminance value of each of the pixels corresponding to each of the exposure positions so as to suppress a change;
When the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and the adjacent pixel of the pixel to be corrected has the minimum luminance value, the luminance value of the adjacent pixel is increased. Do.

According to the light beam exposure apparatus of the second aspect of the present invention, in the light beam exposure apparatus of the first aspect,
The exposure region includes a portion extending along the sub scanning direction,
The above image processing circuit
When the distance between two adjacent exposure positions is shorter than the distance between two adjacent reference positions, the luminance value of the pixel corresponding to at least one of the two exposure positions is decreased,
When the interval between two adjacent exposure positions is longer than the interval between two adjacent reference positions, the luminance value of each pixel is increased by increasing the luminance value of the pixel corresponding to at least one of the two exposure positions. It is characterized in that the value is corrected.

According to the light beam exposure apparatus of the third aspect of the present invention, in the light beam exposure apparatus of the first aspect,
The exposure region includes a portion extending along the main scanning direction,
The plurality of exposure positions adjacent to each other along the sub-scanning direction are first and second exposure positions adjacent to each other, and the first exposure corresponds to a pixel having a luminance value different from the minimum luminance value. A position and a second exposure position corresponding to the pixel having the minimum luminance value,
The above image processing circuit
When the first exposure position is shifted from the reference position of the first exposure position toward the second exposure position, the luminance value of the pixel corresponding to the first exposure position is decreased.
When the first exposure position is shifted from the reference position of the first exposure position in the direction opposite to the second exposure position, the luminance value of the pixel corresponding to the first exposure position is increased. By doing this, the luminance value of each pixel is corrected.

According to the light beam exposure apparatus of the fourth aspect of the present invention, in the light beam exposure apparatus of the first to third aspects,
The image written on the object includes at least a pair of opposing portions, each including a portion of the pair of exposure regions opposing through the non-exposure region,
The pair of facing portions are disposed between the first distance in the main scanning direction, the second distance in the sub scanning direction, and the main scanning direction and the sub scanning direction between the pair of facing portions. Have a third distance in the direction,
When the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction, and the adjacent pixel of the pixel to be corrected has the minimum luminance value, and the image processing circuit is configured to calculate the luminance of the adjacent pixel. Even when the value is increased, the luminance value of the adjacent pixel is increased when all of the first, second and third distances exceed a predetermined threshold value.

An electronic device according to a fifth aspect of the present invention is
A light beam exposure apparatus according to one of the first to fourth aspects;
An input device for acquiring the image data;
And a driving device for moving the object.

A method of operating a light beam exposure apparatus according to a sixth aspect of the present invention,
A plurality of light beams are generated based on image data including a plurality of pixels each having a luminance value of three or more gradations including the maximum luminance value and the minimum luminance value, and the object is scanned by the plurality of light beams. An operation method of a light beam exposure apparatus for writing an image of the image data onto the object;
The image written to the object has at least one exposure region corresponding to a region of a pixel having a luminance value different from the minimum luminance value and at least one non-exposure region corresponding to a region of a pixel having the minimum luminance value. Including an exposure area,
The light beam exposure apparatus has a main scanning direction and a sub scanning direction on the object,
The above operation method is
Correcting the luminance value of each pixel of the image data;
Sending the luminance value of each pixel of the corrected image data to the light emitting device;
Generating a plurality of light beams respectively irradiating different exposure positions adjacent to each other along the sub-scanning direction on the object, and scanning the plurality of light beams in the main scanning direction.
The step of correcting the luminance value of each pixel of the image data is:
The contour shape of the exposure area due to the deviation of each exposure position based on the exposure position information indicating the deviation of each exposure position from the reference position at regular intervals along the sub scanning direction on the object Correcting the luminance value of each pixel corresponding to each exposure position so as to suppress a change;
Increasing the luminance value of the adjacent pixel when the luminance value of the pixel to be corrected exceeds the maximum luminance value by correction and when the adjacent pixel of the pixel to be corrected has the minimum luminance value It is characterized by

10: Host computer,
20: Light beam exposure apparatus,
21 ... image processing circuit,
22: Control circuit,
23-1 to 23-6: light emitting devices,
24A to 24D: light emitting elements,
25 ... deflection device,
26 ... Drive device,
30 ... printed wiring board.

Patent No. 4942176

Claims (4)

An exposure apparatus that irradiates and writes each pixel of input image data with a plurality of light beams along the main scanning direction and the sub scanning direction on the exposure object,
An image processing circuit that corrects the luminance value of each pixel of the image data based on a predetermined setting ;
And generating a plurality of light beams respectively irradiating different exposure positions adjacent to each other along the sub scanning direction on the exposure object based on the corrected image data sent from the image processing circuit. And a light emitting device for scanning the light beam of
The image processing circuit
Each pixel each exposure position of the plurality of light beams, when included in the edge of the exposure area extending along the sub scanning direction, in accordance with the distance between the respective exposure positions, corresponding to the respective exposure positions Correct the brightness value of
Exposure position one light beam of the plurality of light beams, when included in the edge of the exposure area extending along the main scanning direction, wherein the exposure of the equidistant reference position of each exposure position Correct the luminance value of the pixel corresponding to the exposure position according to the position shift .
Exposure device. The exposure apparatus according to claim 1,
The image processing circuit includes an exposure position corresponding to the pixel to be corrected, if included in the edge of the exposed region extending along the sub-scanning direction, predetermined when correcting the luminance value of pixels of the corrected when exceeding the maximum luminance value which is, and, when having a minimum luminance value adjacent pixels of the pixel of the correction target is predetermined, it sets the luminance value of the pixel of the correction target to the maximum brightness value, the neighboring An exposure apparatus characterized by increasing the luminance value of a pixel. The exposure apparatus according to claim 1,
The image processing circuit includes an exposure position corresponding to the pixel to be corrected, if included in the edge of the exposure area extending along the main scanning direction, predetermined when correcting the luminance value of pixels of the corrected when exceeding the maximum luminance value which is, and, when having a minimum luminance value adjacent pixels of the pixel of the correction target is predetermined, it sets the luminance value of the pixel of the correction target to the maximum brightness value, the neighboring An exposure apparatus characterized by increasing the luminance value of a pixel. The exposure apparatus according to any one of claims 1 to 3, wherein the exposure object is a printed wiring board having at least two exposure areas and at least one non-exposure area .
The image processing circuit may exceed the maximum luminance value which the luminance value is predetermined by the correction of the pixel to be corrected Rutoki and when have a minimum luminance value adjacent pixels of the pixel of the correction target is predetermined and the even increasing the luminance values of adjacent pixels, when the distance between the respective exposure regions exceeds a predetermined threshold value of the distance between the wiring of the printed wiring board, the brightness value of the neighboring pixel An exposure apparatus characterized by increasing

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