JP2005251841A - Optical writing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform partition exposure of one image using a plurality of light sources and to write each partition image with a quantity of light within a predetermined range. <P>SOLUTION: A plurality of light sources are arranged to constitute an optical head 1. Quantity of light from each light source arranged in the head 1 is measured at a spot detecting section 7 and its variation is stored as a difference value. The voltage being supplied to each light source is then altered sequentially, and variation in the quantity of light due to variation in voltage is determined at the spot detecting section 7 and stored, as a quantity of light transition value, in a light source characteristics storage section 29. The difference value and the transition value thus stored are read out at an operating section 28 and an inherent voltage value of each light source is calculated. The calculation result is delivered to a light source control section 9 as an emission command signal of each light source. Upon receiving the command, each light source emits light base on data read out from a bit map memory and performs partition exposure on a photosensitive part 2 arranged oppositely to the optical head with a spot having a quantity of light within a predetermined value thus obtaining one writing image. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical drawing apparatus. In particular, a plurality of light sources are used to divide and expose a photosensitive material with an approximate amount of light within a certain range.

An apparatus that draws an image on a light-sensitive material using a light beam is used in various fields. A stepper is known as one of such optical drawing apparatuses. In this method, a pattern such as an IC is created in advance as a mask, the created mask is placed in the optical system, and the reduced image is taken and exposed to the photosensitive material. For this reason, on the light-sensitive material, a material capable of obtaining a wire diameter of about 0.2 μm has been put into practical use and provided to the market. However, it is necessary to prepare a mask in advance, and the apparatus itself incorporates a step mechanism, which inevitably increases the size and cost. Various devices using a polygon mirror are known as devices capable of direct optical drawing without creating a mask in advance. Although there is an advantage that these devices are relatively small and can be manufactured at low cost, must be used just axis ray for the optical system is a scanning system, will correspondingly, the light spot diameter is thicker 10μm The rank is the limit. In many cases, the distance from the polygon mirror surface to the photosensitive material becomes longer due to the installation of the fθ lens. A drawing apparatus using an electron beam is also known. However, according to this apparatus, an ultrafine spot can be obtained, but a unit in which the inside is evacuated is necessary, and drawing must be performed therein.
In order to improve the drawing speed, there is also known a multi-beam method in which a plurality of lasers are directed to one polygon mirror and irradiated on an electrostatic drum. According to this method, there is an advantage that a plurality of beams can be used at the same time. However, there are cases in which the individual light amounts of the generated multi-beams have individuality for each laser light source. In addition, the obtained spot diameter may vary.
JP 2000-89526 A

  It is an object of the present invention to provide an optical drawing apparatus that solves the above problems. That is, it is to provide a small and inexpensive multi-beam optical drawing apparatus. Then, even if a difference in light quantity or spot diameter difference occurs in each of a plurality of light sources mounted to constitute a multi-beam, it is possible to relieve them so that they can fall within a certain range. Another object of the present invention is to provide an apparatus which can obtain a spot by an optical system using only the central optical axis of a lens. Accordingly, it is an object of the present invention to provide an apparatus capable of performing high-speed drawing with an approximate amount of light within a certain range even if one image is divided and output according to the number of light sources.

In order to achieve the above object, according to the present invention, an optical system for projecting a light beam from a light source as a spot is accommodated in a lens cylinder, and an optical head in which a plurality of lens cylinders are arranged, and the optical head is in a first position. A light-sensitive material portion that is placed at a position facing the optical head and receives a spot projected from the optical system; and a position that faces the optical head when the optical head is at the second position, and the optical system A spot detection unit that receives a spot projected from the head and detects the amount of light, and selectively moves the optical head to the first and second positions, and the optical head and the light-sensitive material when in the first position. A feed control unit that moves the position of the unit in the x and y directions, and sequentially changes the supply voltage to the light source to emit light, and the spot detection unit detects a transition value of the amount of light generated for each light source according to the voltage. , Its value A light source characteristic storage unit that stores light emission characteristics for each light source, and a signal that detects the amount of light when the supply voltage to the light source is uniformly emitted by the spot detection unit, and outputs the variation as a difference value; A calculation unit that calculates a specific voltage value for each light source from the light source characteristic value stored in the light source characteristic storage unit, and a specific voltage value from the calculation unit for each light source when the optical head is at the first position. A light source control unit that transmits and emits light, and projects and exposes the spot onto the light-sensitive material part, and the light-sensitive material part is subjected to divided exposure with spots of approximate light intensity within a certain range from a plurality of light sources. It is characterized by.
According to the second aspect of the present invention, an optical system for projecting a light beam from a light source as a spot is accommodated in a lens barrel, and an optical head having a plurality of lens barrels disposed therein, and the optical head are in a first position. A light-sensitive material portion that is placed at a position facing the optical head and receives a spot projected from the optical system; and a position that faces the optical head when the optical head is at the second position, and the optical system A spot detection unit that receives a spot projected from the head and detects the amount of light, and selectively moves the optical head to the first and second positions, and the optical head and the light-sensitive material when in the first position. A feed control unit that moves the position of the unit in the x and y directions, a comparison unit that compares a detection value for each light source from the spot detection unit with a predetermined set value, and outputs the result for each light source, and comparison Comparison A light source control unit that sequentially adjusts the voltage supplied to each light source until the result reaches the set value, and the light source supply voltage when the comparison result reaches the set value for each light source. A light amount setting register for storing as a light source, and when the optical head is in the first position, based on the stored value of the light amount setting register, the light source controller transmits a specific voltage to each light source to emit light, The light-sensitive material portion is divided and exposed by a spot from a plurality of light sources with an approximate amount of light within a certain range.
According to a third aspect of the present invention, an optical system for projecting a light beam from a light source as a spot is accommodated in a lens barrel, and an optical head having a plurality of the lens barrels, and the optical head is in a first position. A light-sensitive material portion that is installed at a position facing the optical head and receives a spot projected from the optical system; and a light-sensitive material portion that is placed at a position facing the optical head when the optical head is at the second position; A spot detection unit that receives the projected spot and detects the amount of light and the focus state from the spot shape, and selectively moves the optical head to the first and second positions, and is in the first position. When the position of the optical head and the light-sensitive material portion is moved in the x and y directions, the light intensity detection value for each light source from the spot detection portion is compared with a predetermined set value, and the result is obtained for each light source. output A comparison unit, a light source control unit that sequentially adjusts the voltage supplied to each light source until the comparison result in the comparison unit reaches a set value, and the comparison result when the comparison result reaches a set value for each light source. A light amount setting register for storing a light source supply voltage as a specific voltage for each light source, and a lens tube drive that receives a focus state detection signal for each light source from the spot detection unit and corresponds a deviation amount with respect to a reference shape as a lens tube movement signal And an arithmetic unit that adjusts the focus position of the spot by moving each lens cylinder in the direction of the optical axis of the optical system, and all the lens cylinders arranged on the optical head are moved and aligned by a lens cylinder movement signal. Later, the light-sensitive material portion is divided and exposed with a spot from the plurality of light sources with an approximate amount of light within a certain range.

  The apparatus according to the present invention is such that one or a plurality of optical heads 1 each having a plurality of light sources are divided and exposed on the photosensitive material to advance the drawing, which also includes a plurality of light sources arranged on the optical head. Even if there are variations in the amount of light and errors in the spot diameter, they are remedied so that light can be emitted with an approximate amount of light within a certain range. Thereby, not only a high-precision image with a small density difference and spot diameter difference can be obtained, but also high-speed drawing can be advanced. Even when the density value of the entire image is changed, it can be handled as a light source having the same characteristics without being bothered by the individuality of each light source. As a whole, an inexpensive optical drawing apparatus can be provided.

  An optical drawing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory schematic block diagram showing the apparatus of the present invention. In the figure, reference numeral 1 denotes an optical head configured by arranging a plurality of light sources such as lasers and LEDs and an optical system (hereinafter collectively referred to as LP) for projecting the spot on a mount, and is illustrated so as to be movable in the x direction. It is attached to the stage on the main body that is not. Reference numeral 2 denotes a light-sensitive material portion, which is attached to a stage on a main body (not shown) so as to be movable in the y direction on a plane parallel to the lower portion of the optical head 1, and is exposed by receiving spots from the LPs. Positioned. 4 is a feed control that moves the optical head 1 and the light-sensitive material portion 2 in the x and y directions to change the positional relationship between the two relative to each other and changes the positional relationship between the spot detection unit and the optical head 1 described later. Part. The feed control unit 4 houses a drive source such as a motor connected to the stage in the x and y directions, its control unit, a current position determination unit for knowing the relative change amount, and the like. Reference numeral 5 denotes an x-direction current position detector that detects the amount of movement of the optical head 1 in the x-direction and transmits it to the feed control unit 4, and 6 indicates the current position in the y-direction that detects the amount of movement of the photosensitive material unit 2 in the y-direction It is a detector. A spot detection unit 7 is installed at a position on the main body equivalent to the light-sensitive material unit 2 and detects the light amount from each LP disposed in the optical head 1. Therefore, the optical head 1 is selectively moved between the first and second positions by the feed control unit 4 described above, and is installed and positioned at a position facing the spot detection unit 7 and the photosensitive material unit 2. When the head 1 is in the second position, the spot detector 7 receives the spot from each LP, detects the amount of light, detects the variation in comparison with a predetermined reference amount of light, and stores it as a difference internally. To do. The stored difference value is read by the control unit 8 and sent to the light source control unit 9. The light source control unit 9 is connected to each LP of the optical head 1 and causes each LP of the optical head 1 to emit light according to the commanded difference value and the supplied uniform voltage, and the light quantity of all LPs is in a certain range. Adjust to fit within. Reference numeral 10 denotes an input unit to the control unit 8 that controls the entire apparatus, and includes a reading device such as an MO or a CD in addition to a mouse and a keyboard.
The optical drawing apparatus according to this embodiment forms one optical head 1 by arranging a plurality of LPs as described above. The head can be freely moved to the first and second positions. When the head is at the second position, the light amount of each LP disposed on the optical head 1 is first measured by the spot detection unit 7, and a predetermined reference value is set. And the variation is stored as a difference value. Next, the optical head 1 is moved to the first position so as to oppose the light-sensitive material unit 2, and light is emitted while adjusting each LP based on the difference value stored in the spot detection unit 7 and the supplied uniform voltage, Each image to be divided and exposed is exposed on the photosensitive material portion 2 as a drawn image with an approximate light quantity within a certain range. Therefore, the optical head 1 defines the second position on the spot detection unit 7 installed at the same position as the photosensitive material unit 2 before starting the drawing operation, and measures the light amount from each LP under the same conditions. After that, the exposure is performed by moving to the first position on the photosensitive material portion 2. This will be described in detail below.

FIG. 2 is an explanatory diagram showing the relationship between a plurality of LPs arranged in the optical head 1 and a drawn image exposed to the photosensitive material 13 installed in the photosensitive material section 2. FIG. 2A shows a state in which four LPs LPa to LPd are arranged along the virtual reference line 11 on the head 1A, each having an interval of dx. When each LP of such an optical head 1A is turned on at the same time and moved by dx in the direction of arrow 12 in the figure by the feed control unit 4, the photosensitive material 13 installed in the photosensitive material unit 2 has four LPa to LPd. Thus, an image 14 having a length X is obtained. That is, the divided exposure image for each LP corresponding to the arrangement interval dx of each LP becomes one X image 14. Therefore, it can be obtained at a speed four times higher than when a drawn image having a length of X is obtained with one LP.
FIG. 2B shows an example in which four columns LPa to LPd are arranged on the optical head 1B along three rows LP1 to LP3 and virtual reference lines 11 and 15. The intervals between the LPs are dx and dy, respectively. It has become. 1 is sent to the optical head 1B from the light source control unit 9 in FIG. 1, and the LPs are simultaneously turned on to move the head 1B by dx in the same direction as the arrow 12 in FIG. 2A. Images of 14-1 to 14-3 are simultaneously obtained on the photosensitive material 13 by each LP. Each of the images 14 is obtained by adding the divided exposure images corresponding to the arrangement interval dx of LPa to LPd to form one image having a length X. When the three images 14-1 to 14-3 are obtained in this way, the photosensitive material 13 is moved in the direction of arrow 16 in FIG. An image 17 having a length Y is obtained by the four LPa to LPd constituting the row. That is, a total of the exposure images of the LPs in the column direction corresponding to the LP interval dy in the row direction becomes one Y image 17, and four images 17 are created. However, in the figure, only an image 17d created in a row of LPd is shown in order to avoid congestion.
As described above, when a plurality of LPs are arranged along the reference lines 11 and 15 and are simultaneously turned on and the head 1 is moved in the direction of the arrow 12, the number of LPs in the row direction (in this case, LP1 to LP3) is obtained. The combined images 14-1 to 14-3 in the x direction are obtained. If the photosensitive material 13 is moved by dy in the direction of the arrow 16 after the image 14 is exposed, images 17a to 17d in the y direction corresponding to the number of LPs in the column direction (in this case, LPa to LPd) are obtained.

FIG. 3 further explains the drawn image obtained on the optical head 1 </ b> C and the photosensitive material 13. FIG. A shows an optical head 1C in which LPs of 3 rows × 3 columns are arranged, and are arranged along virtual reference lines 11 and 15 with an interval of dx and dy. FIGS. BD show the drawn images obtained by the head 1C. In FIG. B, an image 14-1 indicated by a thick arrow is created by exposure from LPa to LPc constituting LP1. The image 14-2 is created by being exposed by LPa to LPc of LP2 arranged at a position separated from LP1 by a distance dy. Similarly, the image 14-3 is created by exposure of LPa to LPc constituting LP3. Accordingly, all the LPs are turned on at the same time, and the three images 14-1 to 14-3 having the length X can be simultaneously obtained by moving the head 1C by dx in the direction of the arrow 12 shown in FIG. 3A.
In FIG. C, an image 18 is created by moving the photosensitive material 13 in the direction of arrow 16 by y1 from the state of FIG. That is, when drawing of the image 14 in FIG. B is completed, the head 1C is moved in the direction opposite to the arrow 12 in FIG. This return operation is performed by operating the feed control unit 4 in response to a command from the control unit 8 and moving the optical head 1C by the feed means. Also during this return operation, a command is sent from the feed control unit 4 to the sensitive material unit 2 and moved in the direction of arrow 16 in FIG. If the optical head 1C is moved in the direction of the arrow 12 in FIG. A while lighting all the LPs, three images 18-1 to 18-3 indicated by solid line arrows can be obtained. Of course, each image 18 is a drawn image created by exposure of LPa to LPc at positions on the photosensitive material separated by an amount corresponding to the LP interval dy on the head 1C as in the case of the image 14. .
In FIG. D, images 19-1 to 19-3 are created by further moving the photosensitive material 13 in the direction of arrow 16 by y1 from the state of FIG. That is, when the exposure of the image 18 in FIG. C is completed, the head 1C is moved in the direction opposite to the arrow 12 in FIG. During this returning operation, a command is sent from the feed control unit 4 to the photosensitive material unit 2 to move the photosensitive material 13 in the direction of arrow 16 by y1. If the optical head 1C is moved in the direction of arrow 12 while all the LPs are turned on, three images 19-1 to 19-3 indicated by dotted arrows can be drawn. This image 19 is a drawing image created by exposure of LPa to LPc at positions separated by an amount corresponding to the LP interval dy on the head 1C as in the case of the image 18.
As described above, the entire optical head 1C having a plurality of LPs is moved in the x direction 12, and the photosensitive material portions 2 installed so as to be moved in the y direction 16 on a plane parallel to the head 1C are sequentially arranged. A plurality of images 14, 18, and 19 can be drawn by moving by y1. In the figure, the images 14, 18, and 19 are shown as a thick line, a solid line, and a dotted line to distinguish them, but it is obvious that the same image is actually obtained. For example, if dx and dy are 5 mm and the beam diameter obtained by each LP is 1 μm, an image with a length of X = 15 mm can be obtained in the example of FIG. Then, 5000 images such as 14, 18, and 19 can be drawn between each dy. In the example of FIG. 3, a 3 × 3 LP is arranged on the head 1C. If this is 8 × 8, a 4 cm square image can be obtained, and a 24 × 24 head can be obtained. For example, a 12 cm square image can be obtained. If the light emission timing of each LP is controlled using such an optical head, an arbitrary image having a size corresponding to the number of LPs can be drawn.

In the optical head 1 described above, a constant LP is provided for all the amounts of light obtained on the photosensitive material surface 13. Therefore, even if one image is divided and exposed by using a plurality of LPs while moving the head 1 and the photosensitive material portion 2, it can be converted into one image. However, the LP arranged in the head varies in the amount of light depending on the position adjustment when attached to the head and the individual characteristics of the light source itself. Unless this variation is absorbed and kept within a certain range, a density difference is generated in the exposed divided image, and an image having a usable quality cannot be created. This will be further described with reference to FIG. FIG. 4 shows, for example, the relationship between the amount of light output from each of the light sources LPa to LPd in FIG. 2A and the image density on the photosensitive material 13 exposed by the light. In FIG. 4A, a curve ca is a light amount on the light-sensitive material portion 2 obtained when the LPa in FIG. 2A emits light, and the brightness at that time is indicated as L1. A curve cb is obtained when LPb in FIG. 2A emits light, and its brightness is indicated as L2. Similarly, the curve cc is obtained when LPc emits light, and the brightness is L3. Curve cd is obtained when LPd emits light, and its brightness is L4.
FIG. 4B shows an example in which the image 14 is created by exposing the photosensitive material 13 with each LP having such light quantity characteristics. In FIG. 4B, 14a is an image exposed by a curve ca by LPa, 14b is a curve cb by LPb, 14c is a curve cc by LPc, 14d is an image exposed by a curve cd by LPd, An image 14 is formed. However, since LPa to LPd have a light quantity difference of L1 to L4, a density difference D also occurs in the image 14 obtained on the photosensitive material 13. In FIG. B, the difference in density difference D is expressed as a step in the height direction. Actually, a difference will occur not only in the density D but also in the width ww, but the description thereof is omitted here. Obviously, if such a density difference occurs in one image 14, it cannot be used as a drawing product. Therefore, in order to make the amount of light with variation constant, it is necessary to obtain a certain reference light amount, for example, a difference value of the light amount with respect to the curve ca.
As described above, the light quantity characteristics based on the irradiation energy distribution of the LP described with reference to FIGS. 4A and 4B relate to the inherent difference that occurs when the voltage value applied to each LP is made uniform. That is, the problem occurs when the voltage supplied to the light source is made uniform regardless of the amount of light obtained from each LP. On the other hand, FIG. 4C explains the problem that occurs when the voltage value supplied to the LP is sequentially changed, and represents the situation in which the amount of light output changes according to the voltage. ing. The figure shows four LP output curves a to d, and the irradiation energy L increases as the supplied voltage W increases. If the curves a to d correspond to LPa to LPd, respectively, L3 is measured as the amount of light (brightness) obtained by the spot detector 7 when the voltage W6 is applied to LPa. Further, when the voltage of W7 is applied to the same LPa, the light quantity of L6 is obtained. A curve connecting the two measurement points L3 and L6 at this time is a. In order to actually obtain the curve a, a more accurate curve can be obtained by setting more measurement points in addition to the two measurement points L3 and L6. If the light source characteristic value is stored in advance, when there is a request to change the spot light amount of LPa, the light amount to be obtained can be obtained by easily calculating the supplied voltage.
Similarly, curve b represents the change in the amount of spot light from the light source obtained when the voltage supplied to LPb is changed, and has the light source characteristics possessed by LPb. Specifically, the light amount is L3 when the voltage is W5, and the light amount is L6 when the voltage is W8 higher than W7 of the curve a. Then, a curve b is obtained by connecting both measurement values L3 and L6. According to this curve b, only the voltage W5 is required in order to obtain the same light quantity L3 with respect to the curve a of LPa. That is, in order to make the LPa and LPb spots have the same L3 light quantity at the image forming point of the spot detector 7, LPa is W6 while LPb is lower than W5. This means that LPb has a variation of (W6-W5) compared to LPa. Therefore, it is necessary to perform voltage adjustment on LPb by an amount corresponding to this difference. If this adjustment is incomplete, an image 14 having a density difference is obtained as shown in FIG. 4B.
A curve c represents the light source characteristic of LPc, and the voltage of W2 is sufficient to obtain the light quantity of L3, and the characteristic of requiring the voltage of W4 to obtain the value of L6. Similarly, curve d represents the characteristics of LPd. To obtain L3, W1 lower than W2 of curve c is sufficient, and to obtain L6, W3 lower than W4 of curve c is sufficient. Yes.
As shown in FIG. 4C, if all the LPs LPa to LPd have variation characteristics as shown by curves a to d, the light amount is uniform even if the voltage is changed to keep the light amount of each LP constant. Does not change. For example, there are some curves a and b whose characteristics are reversed in the middle. Therefore, when the voltage is set to a certain arbitrary value, the value of the amount of light output from the light source must be calculated in advance. For this purpose, the relationship between the voltage and the transition value of the light amount that will change for each LP is calculated in advance and stored as the light source characteristic for each LP, and the light amount of the entire image is set to “3” or “6”. When the stored value is read each time it is set and the light amount difference value of the irradiation energy distribution according to FIG. 4A described above is given to each LP as an absorbed intrinsic voltage value, the spot light amount from all the LPs is within a certain range. It can be an approximate value.
Note that the change of the light amount set point such as L3 and L6 in FIG. C starts the drawing operation due to, for example, the adjustment of the line width of the entire image or the difference in the type and sensitivity of the photosensitive material 13 accommodated in the photosensitive material portion 2. Set often before.

In the present embodiment, the spot detector 7 is used to absorb the variation in the amount of light and obtain a specific voltage value. The detection unit 7 will be described with reference to FIG. FIG. 5 shows a part of FIG. 1 as a block diagram. In FIG. 5, the optical head 1C is provided with 3 rows × 3 columns of LPs as in FIG. 3A. Such a head 1C is moved in parallel from the photosensitive material 2 which is the first position, and is positioned at the second position on the spot detector 7 as shown in FIG. 1, and spot light from each LP is spot detected. The unit 7 can receive light. As shown in FIG. 5, the detection unit 7 includes a condenser lens 20, a light receiving unit 21 such as a CCD or a photodiode, a storage unit 22 that receives and stores a signal from the light receiving unit 21, and the like. There is one light receiving unit 21 for all light sources, and the light amount is always detected under the same conditions.
Now, when each LP of the optical head 1C positioned at the second position on the spot detection unit 7 is sequentially emitted with a set uniform voltage, the light is collected on the light receiving unit 21 by the condenser lens 20. The irradiation energy at the focus position is detected as the amount of light. If the spot detected first is, for example, a spot from LP1 row and LPa column (hereinafter referred to as LP1 · a), an arbitrary value, for example, “3” 23 is detected as shown in FIG. 6A. FIG. 6 explains the detected light amount of the light receiving unit 21 and shows a state in which the light amount is stored in the storage unit 22. If a second spot, for example, a spot from LP1 · b is detected by the light receiving unit 21 as “4” 24 as shown in FIG. 6A, it is stored in a dedicated address of the storage unit 22. When the spot from the third LP1 · c is similarly detected as “7” 25 by the light receiving unit 21, it is stored in a dedicated address of the storage unit 22. Similarly, the light of each LP from LP2 and LP3 is also detected by the light receiving unit 21, and the light amount of all LPs accommodated in the optical head 1 is stored in the storage unit 22. The storage unit 22 has a storage address corresponding to each LP arranged in the optical head 1 in this way, and stores the values detected by the light receiving unit 21.

The control unit 8 includes a control unit 26, a bitmap memory 27, a calculation unit 28, a light source characteristic storage unit 29, and the like. The control unit 26 receives various data from the input unit 10 and manages the entire apparatus, and the bitmap memory 27 stores image data to be drawn. As described with reference to FIG. 1, signals from the current position detectors 5, 6 are transmitted to the feed control unit 4 that operates in response to a command from the control unit 26, and the relative relationship between the optical head 1 and the light-sensitive material unit 2. The positional relationship is changed in the x and y directions, or the optical head 1 is selectively moved to the first and second position values. The calculation unit 28 reads the content stored in the storage unit 22 in the spot detection unit 7 described with reference to FIG. 6A, compares it with a predetermined reference light amount, and calculates the difference. For example, when the light amount “3” 23 of LP1 · a is stored in the storage unit 22 in FIG. 6A, the calculation unit 28 reads it and temporarily stores “3” as a reference light amount therein. Then, a difference due to the variation is calculated in comparison with the light quantity from each LP detected thereafter, and the difference is returned to the storage unit 22 and stored as a difference value. Therefore, since the first detection value “3” 23 is treated as a reference value, it is stored as a difference value “0” 30 as shown in FIG. 6B. However, since the spot from the second LP1 · b is detected by the light receiving unit 21 as the light amount “4” 24, the calculation unit 28 compares the reference amount “3”, calculates “+1” 31 and calculates the difference. It is stored in the storage unit 22 as a value. The light amount “7” 25 from LP1 · c is also calculated as “+4” 32 and stored in the storage unit 22. Thereafter, in the same manner, the light from each LP constituting LP2 and LP3 is detected by the light receiving unit 21, sent to the calculation unit 28, compared with the reference light amount “3”, and the difference is obtained and stored in the storage unit 22. Remember. Of course, the selection of the LP serving as the reference light amount is not limited to the first LP1 · a, and can be arbitrarily set.
The light amount difference value calculated by the calculation unit 28 and stored in the storage unit 22 is sent to the light source control unit 9 in response to a command from the control unit 26. The light source control unit 9 is connected to all the LPs accommodated in the optical head 1 via the signal line 9c, but is uniform when the light amount difference value of the storage unit 22 shown in FIG. Is transmitted to each LP together with the voltage of. Then, each LP emits light based on the image data stored in the bitmap memory 27 and exposes the photosensitive material. Since the signal transmitted to the first LP1 · a is “0” 30, it is sufficient to cause the LP1 · a to emit light while the spot detection unit 7 detects the signal, and the signal transmitted to the second LP1 · b. Since “+1” 31, the light source control unit 9 adjusts so that light is emitted with a light amount reduced by “+1” from LP1 · a. Further, since the signal to LP1 · c is “+4” 32 signal, the light source control unit 9 adjusts the light amount by subtracting the amount corresponding to “+4” compared to LP1 · a. Thereafter, if the same adjustment is performed by the light source control unit 9 for LP2 and LP3, the light-sensitive material can be exposed with an approximate amount of light within a certain range when all the LPs emit light. However, in order to correctly adjust the “+1” 31 and “+4” 32 by the light source control unit 9, it is necessary to obtain the light source characteristics for each LP described in FIG. 4C in advance.

Next, a method for obtaining the above light source characteristics will be described. First, in FIG. 5, the light source characteristic detection mode is input from the input unit 10 and transmitted to the control unit 26. Then, the control unit 26 transmits the mode signal to the calculation unit 28 and also sends it to the feed control unit 4 to position the optical head 1 at the second position so as to face the spot detection unit 7. In this state, the control unit 26 instructs the light source control unit 9 to cause the first light source LP1 · a to emit light at an arbitrary voltage, for example, W6. Then, the light receiving unit 21 detects the spot light amount based on the voltage value as, for example, “3” 23 and stores it in the storage unit 22. The calculation unit 28 receives the command from the control unit 26, reads the contents of the storage unit 22, re-stores the difference value “0” 30 in the storage unit 22, and sets “W6” to the LP1 · a dedicated address in the light source characteristic storage unit 29. = 3 "is written.
The light source characteristic storage unit 29 will be described with reference to FIG. The storage unit 29 has a dedicated address area MP corresponding to each LP arranged in the optical head 1. For example, MP1 • 29a for LP1 • a, MP2 • 29b for LP2 • b, and LP3 • c. , A dedicated address area MP is prepared as in MP3 • 29c. Therefore, when LP1 · a emits light at W6 and is detected as “3” 23 by the light receiving unit 21, the value “W6 = 3” is stored in the address MP1 · 29a of the storage unit 29 via the storage unit 22. Written. Next, the control unit 26 instructs the light source control unit 9 to change the voltage applied to LP1 · a to W1, and causes it to emit light. Then, the light receiving unit 21 detects the light amount “W1 = na1” at that time, temporarily stores it in the storage unit 22, and sends it to the addresses MP1 and 29a of the light source characteristic storage unit 29 in response to a command from the control unit 26. Thereafter, the voltage is sequentially changed to W2, W3... To cause the light source LP1 · a to emit light, and the light quantity “W2 = na2, W3 = na3. Data is written in the addresses MP1 and 29a of the storage unit 29. When the voltage is thus set to W7, the light amount “6” is detected by the light receiving unit 21, and the value is written in the addresses MP1 and 29a. As a result, the values forming the curve a in FIG. 4c are obtained in the addresses MP1 and 29a by the respective measurement points W1, W2 and W7. In order to explain this, FIG. 7 shows a curve connecting the measurement point 33 when the light amount “6” is obtained at W7 and the measurement point 23 when the light amount “3” is obtained at W6. The value corresponding to the curve a stored in this way becomes the light quantity transition value generated by the voltage change of LP1 · a.
Next, the control unit 26 sends a command to the light source control unit 9 to cause the second light source LP1 · b to emit light at the same W6 as in the case of LP1 · a. Then, the light receiving unit 21 detects the spot light amount based on the voltage value at that time, and the calculation unit 28 compares it with the reference value of LP1 · a to obtain the difference value, and stores it as “+1” 31 in the storage unit 22. Further, “W6 = nb6” is stored in the addresses MP1 and 29b of the storage unit 29. Next, in response to a command from the control unit 26, the light source control unit 9 sequentially changes the voltage to W1, W2,. Then, the light receiving unit 21 detects a change in the amount of light as the voltage is changed to W1, W2,... W8..., When the voltage W1 is “nb1”, when W2 is “nb2”. When “3” and W8, “6” is obtained. The measurement points when “3” and “6” were obtained are shown as 34 and 35 in the addresses MP1 and 29b of FIG. The value corresponding to the curve b in FIG. 4C obtained by connecting the fixed points on both sides is the light amount transition value generated by the voltage change of LP1 · b.
Similarly, a voltage W6 is applied to the third light source LP1 · c from the light source controller 9 to emit light. Then, the light receiving unit 21 detects the light amount “W6 = nc6” at that time. The calculation unit 28 compares the value with the reference value of LP1 · a to obtain the difference value, and stores “+4” 32 in the storage unit 22. Further, “W6 = nc6” is stored in the addresses MP1 and 29c of the storage unit 29. Next, the light source controller 9 sequentially changes the voltage to W1, W2,... And gives a light emission command to the light sources LP1 and c. Then, the light receiving unit 21 detects the change in the light amount as the voltage changes to W1, W2,... W4..., “Nc1” when the voltage is W1, “3” when W2, and “6” when W4. Get. The measurement points when "3" and "6" were obtained are shown as 36 and 37 in the addresses MP1 and 29c of FIG. A value corresponding to the curve c in FIG. 4C obtained by connecting the fixed points on both sides is a transition value generated by changing the light quantity of LP1 · c. Thereafter, the transition value is obtained for each LP constituting LP2 and LP3 in the same manner and stored in the respective addresses MP2 and MP3 of the light source characteristic storage unit 29.
Thus, while changing the voltage supplied to the light source, a transition value of the amount of light that changes for each light source is calculated, and is stored in the storage unit 29 as a characteristic for each light source. When the storage operation for all the LPs of the optical head 1 is completed, the light source characteristic detection mode described above is canceled and the actual drawing operation is started. Since LP1 · a is the reference light amount, “0” 30 is commanded from the light source control unit 9. In LP1 · b, the voltage when the calculation unit 28 reads the difference value “+1” from the storage unit 22 and obtains the light amount of the value obtained by subtracting “+1” from the address MP1 · 29b of the light source characteristic storage unit 29. A value is obtained and sent to the light source control unit 9 as a specific voltage value of the light source LP1 · b. Thus, LP1 · b can emit light with a light amount equal to or close to the light amount of LP1 · a.
Next, the control unit 26 reads the difference value “+4” of the light sources LP1 · c from the storage unit 22, and based on the difference value, the light amount of the value obtained by subtracting “+4” from the address MP1 · 29c of the light source characteristic storage unit 29 is obtained. The obtained voltage value is obtained and sent to the light source control unit 9 as the intrinsic voltage value of the light source LP1 · c. Thus, LP1 · c can emit light with an amount of light equal to or similar to LP1 · a and LP1 · b. In the same manner, for each LP constituting LP · 2, LP · 3, a unique voltage value is obtained and sent to the light source control unit 9 to emit each LP. It can be exposed. The light source characteristic detection mode can be set not only when the light quantity measurement points such as L3 and L6 are changed, but also as a running test before starting the drawing operation, thereby improving the density management quality.

Next, Example 2 will be described with reference to FIG. According to this embodiment, the light source characteristic storage unit 29 is eliminated from FIG. 5 and a comparison unit 38 is newly installed so that the intrinsic voltage value required for each light source is obtained each time.
In FIG. 8, each spot from the plurality of LPs arranged on the optical head 1 </ b> C is collected by the light receiving unit 21 through the condenser lens 20 in the spot detection unit 7 a and heads for the comparison unit 38. A setting value of light quantity that is input and set in advance from the input unit 10, for example, “3”, is transmitted to the comparison unit 38 and is compared with the detection value from the light receiving unit 21. If the detection value from the light receiving unit 21 is from LP1 · a, “3” is compared by the comparison unit 38 as shown in FIG. 6A, and the result is “0”. The comparison result is stored in the light amount setting register 39 in the light source control section 9a through the signal line 38a. This register 39 is prepared for each LP. For example, the comparison result of LP1 · a is stored in a register 391a (not shown) dedicated to LP1 · a. In this case, since the comparison result is “0”, “0.0” is stored in the register 391a as the inherent voltage of LP1 · a. Next, LP1 · b is compared. When the spot light from LP1 · b is detected by the light receiving unit 21 as “4”, for example, the comparison unit 38 determines that the set value “3” is positive. -"Signal is sent from the signal line 38a to a predetermined register 391b (not shown). Then, the register 391b receives the “−” signal and changes the value from the initially set value “0.0” to “−1.0”, for example. When “−1.0” is stored in the register 391b, the light source control unit 9a reads out the content, lowers the voltage corresponding to the value of “−1.0”, and sends it to LP1 · b. When LP1 · b emits light at the commanded voltage, the light receiving unit 21 detects the amount of light, and obtains, for example, “3.9” which is lower than the initial “4”. When the spot light corresponding to “3.9” is sent to the comparison unit 38 in the same manner as in the above case, the comparison unit 38 compares with the set value “3”, and as a result, it is determined that it is still positive, and “−”. Send a signal. The register 391b receives this “−” signal and changes its content from “−1.0” to “−2.0”. The light source controller 9a reduces the voltage corresponding to “−2.0” and transmits it to LP1 · b to emit light. Then, the light receiving unit 21 detects the amount of light and obtains, for example, “3.8”. Thereafter, in the same manner, when the value of the register 391b becomes “−10.0”, the light receiving unit 21 detects the light amount “3”, and the comparison unit 38 indicates that the set value “3” is equivalent to or an approximate value thereof. The “−” signal is converted to “0” and transmitted to the register 391b. The register 391b subsequently holds the light source supply voltage value “−10.0” at this time as the inherent voltage of LP1 · b.

Next, the intrinsic voltage of LP1 · c is obtained. First, assume that LP1 · c is caused to emit light at the same voltage as that applied to LP1 · a, and for example, “7” is obtained. The comparison unit 38 compares this with the set value “3”, determines that the value is positive, and transmits a “−” signal to the register 391c. The register 391c receives the “−” signal and changes the content from an arbitrary value “0.0” that has been initially set to “−1.0”. Then, the light source control unit 9a reads out the value and reduces the voltage by an amount corresponding to “−1.0” to cause LP1 · c to emit light. As a result, the light receiving unit 21 detects “6.9” having a value lower than the initial “7” and sends it to the comparison unit 38, but the comparison unit 38 still determines that it is positive and transmits a “−” signal. Thereafter, in the same manner, when the register 391c becomes “−40.0”, the light receiving unit 21 detects the light quantity of LP1 · c as “3”, and the comparison unit 38 thereby determines that the set value is equivalent to “0”. Is output. The register 391c thereafter holds the inherent voltage of LP1 · c as “−40.0”.
Thereafter, the specific voltage of each of LP2 and LP3 is obtained in the same manner. However, the light receiving unit 21 detects “2” as the light amount smaller than the set value “3”, for example, the light amount of LP2 · b as shown in FIG. 6A. If so, the comparison unit 38 determines that the value is negative and transmits a “+” signal from the signal line 38 a to the register 392 b (not shown). When the register 392b receives the “+” signal, the content is changed from the set arbitrary value “0.0” to “+1.0”, and the light source control unit 9a reads the content to “+1.0”. The corresponding voltage is added and transmitted to LP2.b. When LP2 · b emits light at the commanded value, the light receiving unit 21 detects “2.1”, which is a value higher than “2”, and the comparison unit 38 compares it with the set value. However, the comparison unit 38 still determines that the value is negative, and sends a “+” signal to the register 392b. Thereafter, in the same manner, when the register 392b becomes “+10.0”, the light receiving unit 21 detects the light amount “3” or an approximate light amount thereof, and the comparing unit 38 determines that the set value is equivalent and outputs a “0” signal. To do. Thereby, the register 392b holds and stores “+10.0” as the inherent voltage of LP2 · b.
As described above, in this embodiment, in order to obtain the inherent voltage of each LP, the comparison unit 38 compares the set value set in advance in the comparison unit 38 as the calculated value with the light amount from each LP detected by the light receiving unit 21. The voltage supplied to each LP is adjusted until the result becomes “0” or an approximate value thereof, and each register is set to “0” or the value obtained when the approximate value is obtained as a specific voltage. 39. Accordingly, when the set value is changed from “3” to “6”, the same operation may be performed, and the transition value of the light quantity characteristic storage unit 29 described in the first embodiment is not necessary. Therefore, the whole work is simplified and programming becomes easy. It should be noted that the value when the contents of the register 39 are changed according to the determination result of “+” and “−” of the comparison unit 38 is only when the step is performed in units of “1” as described above. It is obvious that it can be designed arbitrarily.

Next, Example 3 will be described. In the third embodiment, the spot detection unit 7 described in the first and second embodiments has a function of detecting and managing the spot diameter, so that each of the divided and exposed images has an approximate amount of light within a certain range and within a certain range. The drawing with the line width of can be done.
In FIG. 9, a plurality of lens cylinders 42 that hold a light source 40 and an optical system 41 that projects the spot are held on the mount of the optical head 1. A voice coil 43 is attached to the outer periphery of each lens cylinder 42, and when receiving a command from the lens cylinder driving section 44, the lens cylinder 42 is moved in the optical axis direction. Such driving means 43 and 44 are installed corresponding to each LP. The light beam from the light source 40 forms an image once on the temporary image formation surface 45 through the optical system 41, and further passes through the lens 46 in the spot detection unit 7b, the two cylindrical lenses 47 in the X and Y directions, and the light receiving unit through the objective lens 48. 21 is imaged. The output from the light receiving unit 21 is transmitted to the comparison unit 38 in the control unit 8 and compared with the set value from the input unit 10 as described with reference to FIG. 8, and the result is a light amount setting register in the light source control unit 9b. 39 is sent out.
Next, the shape of the spot obtained by the light receiving unit 21 will be described with reference to FIG. As described with reference to FIG. 4A, the shape of the spot also changes depending on the level of irradiation energy at the focus position, but also greatly changes depending on the focus state when an image is formed on the light receiving unit 21. For example, when the light flux from LP1 · a forms an image on the light receiving unit 21, the spot plane cross section is a circle 49 in FIG. 10A for convenience. Assume that a spot from another light source, for example, LP1 · b, is focused on a position 21a indicated by a dotted line in the spot detector 7b in FIG. Then, since this focal position 21a moves to the optical head 1 side with respect to the regular light receiving portion 21 surface, the cylindrical lens 47 acts, and the spot shape obtained on the light receiving portion 21 is the right as shown by 50a in FIG. 10A. It becomes a falling ellipse. Further, it is assumed that a spot from another light source, for example, LP1 · c, is focused on a position 21b indicated by a dotted line in the spot detector 7b of FIG. Then, since the focal position 21b is located in a direction away from the normal light receiving portion 21 surface, the spot shape obtained on the light receiving portion 21 by the action of the cylindrical lens 47 is as shown by 50b in FIG. 10A. It becomes an elliptical shape rising to the right. At any time, a difference occurs in comparison with the shape of the spot 49 when the normal position 21 is in focus. Therefore, a difference occurs in the spot diameter depending on the focus state. That is, in order to confirm the spot focal position of each LP accommodated in the head 1, a cylindrical lens 47 is installed in the spot detection unit 7b, and when an error occurs, the spot shape is positively changed. A large difference is created as an ellipse 50 with respect to the circle 49. If exposure is carried out using an optical head in which the spots 49 and 50 are mixed, the image 14a (FIG. 10B) created by the spot 49 in FIG. 10A and the image 14b created by the spot 50 have an error. It will be exposed as it is. In FIG. 10B, the line widths of both are shown as 14aw and 14bw, but it is clear that the drawing quality is significantly impaired. Therefore, it is important to perform the work for making the spot diameter constant or for adjusting the focal position of each spot before the work for making the light quantity for each LP constant.

In order to eliminate the error as described above, first, the spot shape management mode is selected from the input unit 10 in FIG. Upon receiving this spot shape management mode command, the control unit 26 sends a command to the light source control unit 9b in FIG. 9 to cause the arbitrary LP of the optical head 1, for example, LP1 · a to emit light. Then, the spot is once imaged on the primary imaging surface 45 by the optical system 41, and imaged on the light receiving unit 21 through the lens 46, the cylindrical lens 47 and the objective lens 48. The light receiving unit 21 is configured by, for example, a four-divided photodiode, and the output from each of the four divided photodiodes is sent to the comparison unit 38 in the control unit 8 when receiving spot irradiation. At the same time, the signal from the light receiving unit 21 is also sent to the calculation unit 28 in the same control unit 8 to identify the state where each of the four photodiodes of the four-divided photodiodes is irradiated, and the spot 49 in FIG. 50a and 50b are determined.
First, if the first LP1 · a is focused on the reference light-receiving surface 21 in accordance with the above-described example, the calculation unit 28 determines the spot shape to be 49 in FIG. 10A, for example, and the lens in the light source control unit 9b. A signal is transmitted to the cylinder driving unit 44. In this case, the drive unit 44 does not operate and the lens tube 42 does not move. On the other hand, the signal sent to the comparison unit 38 is compared with the set value set in advance as described above, and “0”, “+”, “−” are judged, and the result is sent to the register 39. The amount of light sent out is determined. However, in the present example, the comparison unit 38 determines “0” as the amount of light equivalent to the set value “3”, and therefore the register 39 does not operate. Next, the spot of the second LP1 · b is detected by the light receiving unit 21, and the calculation unit 28 determines, for example, 50a in FIG. 10A from the spot shape, and the focus position corresponding to the generated focus error is determined. The correction command is transmitted to the lens barrel drive unit 44 for LP1 · b. The driving unit 44 receives the focus state detection value for each light source, operates the voice coil 43, moves the lens tube 42 in the optical axis direction, and gradually moves the focal position at the position 21a in FIG. 9 to the reference light receiving surface 21. Move closer to the position. During this time, the light receiving unit 21 grasps the situation in which the spot shape 50a gradually approaches the basic shape 49 as a deviation amount, so that the calculation unit 28 solves the command signal to the drive unit 44 when the reference shape 49 is reached. . While the operation of detecting the amount of deviation from the focus state or the basic spot shape is in progress, the comparison unit 38 performs the operation of comparing the set light amount and the detected light amount, and obtains the specific voltage and stores it in the register 39. I will do it. In this way, adjustment work is performed to keep the spot shapes and light amounts of LP1 · a and LP1 · b within a certain range.
Next, when the third spot LP1 · c is detected by the light receiving unit 21, the calculation unit 28 determines the spot shape as 50b in FIG. 10A and transmits a correction command to the lens barrel drive unit 44 of LP1 · c. . The drive unit 44 operates the voice coil 43 to move the lens cylinder 42, and brings the focal position at the position 21b in FIG. 9 closer to the reference light receiving surface 21 position. When the timing when the light receiving unit 21 becomes the reference shape 49 is detected, the calculation unit 28 solves the command to the drive unit 44. During this time, the comparison unit 38 continues the comparison operation, obtains a unique voltage for each LP, and stores and saves it in the register 39. When the operation of keeping the spot shapes and light amounts of LP1 · a to LP1 · c within a certain range is completed in this way, the same procedure is performed for LP2 and LP3 to adjust the spot shapes and light amounts of all LPs.
As described above, in the third embodiment, the spot detector 7b first receives a spot from each LP, detects the spot shape at that time, and moves the position of the lens cylinder 42 for each LP in the optical axis direction according to the difference. Align and adjust the position of all LPs. Further, the detection signal from the spot detection unit 7 b is also sent to the comparison unit 38 to be compared with the set light amount value, the specific voltage for each LP is obtained from the comparison result, and the value is stored in the register 39. As a result, the spot shape (diameter) and light amount of all LPs were kept within a certain range. In order to apply the third embodiment to the first embodiment, the comparison unit 38 in FIG. 9 is replaced with the storage unit 22 and the light source characteristic storage unit 29 in FIG. 5, and the register 39 in FIG. May be read as a storage unit in the light source control unit 9 that stores the natural voltage sent from the.

  As described above, the description has been made based on the three embodiments. However, the optical head 1 may be only one line shown in FIG. 2A, or a plurality of optical heads may be installed to deal with a large area image. I can do it. For example, when the above-mentioned dx and dy are 5 mm and an 8 × 8 LP is arranged in the optical head 1, it is possible to draw only an image of 4 cm square. However, if two heads are installed and connected, an image having a double size can be obtained. Even in this case, it is necessary to measure the spot diameter and the amount of light for each LP by the spot detector 7 before starting the drawing operation, and to adjust the specific light emission voltage of each LP based on the result.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Explanatory drawing which showed the relationship between the image obtained by an optical head and a photosensitive material part. Explanatory drawing which showed the relationship between the image obtained by an optical head and a photosensitive material part. Explanatory drawing which showed the relationship between the light source light quantity and the image density obtained in a sensitive material part. The block diagram which showed the one part detail of FIG. The figure explaining the detection light quantity of a light-receiving part. FIG. 6 is an explanatory diagram of a light source characteristic storage unit illustrated in FIG. 5. FIG. 5 is a schematic block diagram for explaining a second embodiment. FIG. 6 is a schematic block diagram for explaining a third embodiment. The figure explaining the spot shape of a light source.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical head 2 ... Sensitive material part 4 ... Feed control part 5, 6 ... Current position detector 7 ... Spot detection part 8 ... Control unit 9 ... Light source control part DESCRIPTION OF SYMBOLS 10 ... Input part 13 ... Sensitive material 20 ... Condensing lens 21 ... Light-receiving part 22 ... Memory | storage part 26 ... Control part 27 ... Bitmap memory 28 ... Calculation part DESCRIPTION OF SYMBOLS 29 ... Light source characteristic memory | storage part 38 ... Comparison part 39 ... Light quantity setting register 40 ... Light source 41 ... Spot projection optical system 42 ... Lens cylinder 43 ... Voice coil 44 ... Lens tube drive unit 45 ... Primary imaging plane 46 ... Lens 47 ... Cylindrical lens 48 ... Objective lens 49, 50 Spot cross section

Claims (3)

  An optical system for projecting a light beam from a light source as a spot is housed in a lens tube, and an optical head provided with a plurality of the lens tubes and a position facing the optical head when the optical head is in the first position. A light-sensitive material portion that receives a spot projected from the optical system; and a light-sensitive material portion that is installed at a position facing the optical head when the optical head is at the second position and receives the spot projected from the optical system. And a spot detector for detecting the position of the optical head and the optical head selectively moved to the first and second positions, and at the first position, the positions of the optical head and the photosensitive material part are moved in the x and y directions. The feed control unit and the supply voltage to the light source are sequentially changed to emit light, the transition value of the light amount generated for each light source according to the voltage is detected by the spot detection unit, and the value is used as the light emission characteristic for each light source. Remember The light source characteristic storage unit and the spot detection unit detect the amount of light when the supply voltage to the light source is uniformly emitted, and the variation is output as a difference value and stored in the light source characteristic storage unit A calculation unit that calculates a specific voltage value for each light source from the light source characteristic value; and when the optical head is at the first position, each light source transmits the specific voltage value from the calculation unit to emit light, and the spot is An optical drawing apparatus comprising: a light source control unit that projects and exposes to the light sensitive part, and the light sensitive part is divided and exposed by a spot with a light amount approximating a certain range from a plurality of light sources.   An optical system for projecting a light beam from a light source as a spot is housed in a lens tube, and an optical head provided with a plurality of lens tubes and a position facing the optical head when the optical head is in the first position. A light-sensitive material portion that receives a spot projected from the optical system; and a light-sensitive material portion that is installed at a position facing the optical head when the optical head is in the second position and receives the spot projected from the optical system. And a spot detector for detecting the position of the optical head and the optical head selectively moved to the first and second positions, and at the first position, the positions of the optical head and the photosensitive material part are moved in the x and y directions. The control unit that compares the detection value for each light source from the spot detection unit with a predetermined set value and outputs the result for each light source, and the comparison result in the comparison unit becomes the set value. Up to each light source A light source control unit that sequentially adjusts the voltage to be applied, and a light amount setting register that stores a light source supply voltage when the comparison result becomes a set value for each light source as a specific voltage for each light source, When the optical head is in the first position, the light source control unit transmits a specific voltage to each light source based on the stored value of the light amount setting register, and emits light. An optical drawing apparatus characterized in that the photosensitive material part is divided and exposed.   An optical system for projecting a light beam from a light source as a spot is housed in a lens tube, and an optical head provided with a plurality of the lens tubes and a position facing the optical head when the optical head is in the first position. A light-sensitive material portion that receives a spot projected from the optical system; and a light-sensitive material portion that is installed at a position facing the optical head when the optical head is in the second position and receives the spot projected from the optical system. A spot detection unit for detecting a focus state from the spot shape, and selectively moving the optical head to the first and second positions, and when the optical head and the light-sensitive material unit are at the first position, A feed control unit that moves the position in the x and y directions, a comparison unit that compares the light amount detection value for each light source from the spot detection unit with a predetermined set value, and outputs the result for each light source; and a comparison unit comparison A light source control unit that sequentially adjusts the voltage supplied to each light source until the result reaches the set value, and the light source supply voltage when the comparison result reaches the set value for each light source. As a light quantity setting register to be stored and a focus state detection signal for each light source from the spot detection unit, a deviation amount with respect to a reference shape is output as a lens cylinder movement signal to a corresponding lens cylinder driving unit, and each lens cylinder is optically A calculation unit that moves in the optical axis direction of the system and adjusts the focus position of the spot, and after all the lens tubes arranged on the optical head are moved and aligned by the lens tube movement signal, within a certain range from the plurality of light sources. An optical drawing apparatus characterized in that the photosensitive material part is divided and exposed with a spot with an approximate amount of light.