JPH06407B2 - Optical drawing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention irradiates a spot pattern with light, projects the obtained light spots on a photosensitive material, and continuously moves them relative to a ruled line. The present invention relates to an optical drawing device such as a phototypesetting machine or a plotter designed to draw.

[Prior Art and Problems] Conventionally, in order to draw a line such as a ruled line with a phototypesetting machine or the like, recording is performed by relatively moving the photoconductor and the light spot while projecting the light spot on the photoconductor. The spot pattern used to create the light spot used at this time was generally rectangular or square, as indicated by 11 in FIG. This is because the conventional apparatus was mainly configured to process only straight lines in the X and Y directions, but it was also for reproducing the start and end line ends of the ruled line at right angles.

Further, in the rectangular spot pattern, the rectangular light spot obtained by irradiating light on the rectangular spot pattern is arranged in two directions (that is, X
Direction, Y direction) to draw a line, the lengths of the sides parallel to the traveling direction of the putter are the same, so the amount of light received by the photosensitive material is substantially uniform over the entire area. There is an advantage that the image exposed on the object becomes a uniform line without density unevenness.

Therefore, if a plurality of such patterns 11 are prepared in advance according to the thickness of the ruled line, the ruled line having the required thickness can be drawn by selectively using them.

By the way, in such a rectangular pattern 11,
It is suitable for drawing straight lines in the Y direction, but not suitable for drawing curves. FIG. 1 is a view showing a state in which a rectangular light spot is drawn in a curve by changing the direction in which the light spot advances little by little.
In the figure, the alternate long and short dash line indicates the traveling direction of the pattern 11,
Reference numerals 11a, 11b, and 11c show patterns in which the light spots formed by this pattern move. Pattern 1
If 1 moves in parallel to its side, its line width is W ₁ and W ₂ , but when moving diagonally, the thickness of the line changes to W ₃ as shown by the dotted line in the figure. (W
₃ <W ₁ ).

Therefore, it is conceivable to use a circular spot pattern 21 as shown in FIG. 2A so that a line can be drawn with the same width in any direction. However, this spot pattern 21
Of exposure dose when moving to draw a straight line or curve 22
As shown in FIG. 2B, the exposure amount in the central portion of the line becomes significantly larger than the exposure amount in the peripheral portion when viewed from the direction in which the pattern advances (the direction of the arrow in the figure). The contour is blurred.

When the brightness of the light beam that illuminates the pattern is increased,
The exposure amount at the center becomes strong and a phenomenon of fogging occurs, and the line becomes thicker than the diameter W of the pattern.

Furthermore, in order to change the thickness of the ruled line, it is necessary to prepare a plurality of types in which the diameter W of the pattern is changed as in the case of the rectangular spot pattern. If the diameter of the light changes, the amount of light passing through also changes. If the moving speed of the light spot is constant, the exposure amount is proportional to the area of the pattern.Therefore, if the light amount is adjusted to a pattern with a small diameter, the light amount of the pattern with a large diameter becomes excessive, and the density of the line to be exposed rises too much. Fog phenomenon occurs. That is, if the size of the pattern is changed, the intensity of the light beam must be changed accordingly.

Therefore, it is considered that the spotter pattern itself has an exposure amount adjusting function. As such, for example, as disclosed in Japanese Examined Patent Publication No. 47-39886, there is known an annular spot pattern in which the central portion of the pattern is shielded so as not to transmit light. In this annular pattern, the exposure amount can be made constant by making the width of the annular opening band constant regardless of the diameter of the circle.

FIG. 3 shows how ruled lines are drawn by such an annular pattern. At the start point and the end point 31 of the shaded line, only half the exposure amount can be obtained as compared with the intermediate portion 32 shown by the double shaded line. Therefore, it is unavoidable that the density at the end of the line becomes low and the line feels soft.

A method of adjusting the light quantity by providing a filter having an appropriate transmittance at the center of the circular spot pattern shown in FIG. 2 is also conceivable. If the diameter of the pattern is large, a filter with a low transmittance is provided to reduce the exposure amount.If the diameter of the pattern is small, a filter with a high transmittance is provided to increase the light amount. The quality of ruled lines can be standardized. However, providing a filter having a different transmittance depending on the diameter of the circular spot pattern is a difficult process and is not preferable in manufacturing.

[Object of the Invention] The present invention is an optical drawing device that draws a line on a photosensitive material by projecting a light spot on the photosensitive material and moving the both relatively, and a ruled line of a constant quality is recorded on the photosensitive material. It is an object of the present invention to provide an optical drawing device.

A second object is to provide an optical drawing device having a spot pattern that allows a predetermined work to be performed under a constant condition without adjusting the light amount according to the size of the spot pattern to be used. .

Furthermore, the third purpose is to adjust the width of the circular ring according to the thickness of the ruled line or to provide a filter with different density,
An object is to provide an optical drawing apparatus having a spot pattern that can be easily manufactured by a simple method.

In order to achieve such an object, the present invention irradiates a spot pattern with light to project a light spot on a photosensitive material and continuously moves the light spot to draw a ruled line. The aperture pattern is arranged spirally in a predetermined circular area to form the spot pattern.

[Embodiment of the Invention] FIG. 4 shows the principle of a spot pattern used in the present invention. In the spot pattern 41, a large number of translucent dots 42 are spirally arranged. Reference numeral 43 in FIG. 4B indicates the distribution of the exposure amount when the pattern 41 is irradiated. When the dots are formed in a spiral shape,
If the pitch P between the dots is constant, the inner and outer dots do not overlap in the radial direction of the spot pattern 41.

When such a pattern 41 is irradiated with light, the light is transmitted through the translucent dots 42 to expose the photosensitive material. A ruled line can be drawn by moving the photoconductor and the light spot relatively. Therefore, if the dots are spirally distributed (number and size) according to the diameter of the spot pattern, the exposure amount can be kept constant regardless of the thickness of the ruled line. In other words, a spot pattern having a large diameter has a large pitch P, and a spot pattern having a small diameter has a small pitch P and dots are formed (assuming the dots have the same size).

If you draw a ruled line with such a spot pattern, for example,
Since it is possible to suppress the peak lower than the peak of the exposure distribution 22 in FIG. 4B, as in the distribution 43 in FIG. 4B, halation and fog phenomena can be greatly reduced. Further, at the starting point and the ending point of the ruled line, the exposure amount can be evenly distributed over the entire pattern as compared with the annular pattern illustrated in FIG. 3, so that the decrease in density can be suppressed.

FIG. 5 explains the reason why dots are arranged irregularly. A fifth transparent dot 52 is temporarily placed in the circular area.
Assuming that they are arranged regularly as shown in Fig. (A) and the light spots obtained thereby are moved in the direction of the arrow,
As shown in FIG. 5B, a difference occurs in the exposure amount depending on the position where the dots are arranged, and unevenness occurs in the exposure distribution 53.

Therefore, in the present invention, no matter how the light spot moves,
In order to create a ruled line having no density unevenness, dots are arranged in a spiral shape as shown in FIG. 4A so as to prevent regularity from occurring. Such a dot arrangement can be easily obtained by a formula expressing a spiral.

FIG. 6 shows another embodiment of the spot pattern, which is an example in which a light-transmitting continuous opening portion 62 is spirally formed in the spot pattern 61. The exposure amount can be adjusted by adjusting the width of the opening.

In each of the above embodiments, the dots arranged in the predetermined circular area are light-transmissive, but conversely, light-shielding dots may be formed in the light-transmissive circular area.

Further, the openings to be arranged in the circular area are not limited to dot-shaped ones and continuous ones, but may be elliptical dots, and the size of the dots and the width of the openings may be changed between the peripheral portion and the central portion of the circular area. You can also

FIG. 7 illustrates an apparatus for drawing a ruled line on a photosensitive material by using a dial containing a plurality of spot patterns having different diameters as described above, taking a phototypesetting machine as an example.
Reference numeral 71 is a light source, and light is condensed by a condenser lens 72, and its optical path is changed by a prism or mirror 73. The dial 74 includes a plurality of spot patterns as described above as well as characters and symbols. A desired pattern is selected by moving the dial in the XY directions and set at the optical axis position. The set pattern is irradiated with light from the light source, passes through the main lens 75 and the deforming lens 76, undergoes optical path conversion by the prisms 77 and 78, and forms an image on the photosensitive material 79. A shutter 80 controls exposure. Further, the light spot is moved by moving the prism 78 left and right in the drawing and rotating the drum holding the photosensitive material 79. This movement is performed by the pulse motor 81 or the like, but various control devices 82 for constant speed movement may be publicly known.

In order to draw a straight line on the photosensitive material with such an apparatus, the coordinates of the start point and the end point or the length of the ruled line are input from an input unit (not shown), and if the start of exposure is commanded, the shutter 80 is released and the prism is released. The drum holding 78 or the photosensitive material 79 operates to move the light spot according to the set spot pattern. The light spot at this time is the main lens 7
5. Although it is affected by the magnification of the optical system such as the deformable lens 76, the desired straight line can be recorded arbitrarily.

To draw a curve, if the radius r that specifies the size of the curve and the coordinates of the start and end points are input, the shutter 80 operates in the same way as in the case of a straight line, and the prism 78 and the photosensitive member 79 are driven simultaneously. A curve having a curvature corresponding to the designated radius r can be reproduced on the photosensitive material.

Of course, it is obvious that the effect of the present invention is greater when the spot pattern diameter is larger than when the spot pattern diameter is small. Further, as described above, since the dial 74 contains not only the spot pattern but also the characters and symbols,
If they are used together and exposed on the photosensitive material, it is possible to create a printed material with characters and ruled lines together as specified.

Furthermore, if a spot pattern is used not only with a phototypesetting machine having an optical system as shown in FIG. 7 but also with an arbitrary optical plotter, ruled lines can be recorded on the photosensitive material in the same manner.

[Effects of the Invention] As described above, according to the present invention, the translucent or light-shielding openings are arranged in a predetermined circular area in a spiral distribution arrangement spot pattern. The contour can be drawn sharply on the photosensitive material with a constant quality without being caught. Since the necessary light amount adjustment is also performed on the spot pattern, it is possible to draw ruled lines having different thicknesses under a certain condition without adjusting the light amount from the light source according to the thickness of the ruled line. Also,
Instead of providing a filter with an analog density change in the spot pattern, it is possible to deal with the dots of the binary image, so it does not take much time to produce, and it is possible to produce with stable quality.

[Brief description of drawings]

FIG. 1 shows an example of the implementation of the present invention.
FIG. 3 is a conventional explanatory diagram, FIG. 4 is a diagram for explaining the principle of the spot pattern used in the present invention, FIG. 5 is a diagram for explaining the reason for arranging in a spiral shape, and FIG. 6 is for other spot patterns. FIG. 7 is a diagram showing an example, and FIG. 7 is a diagram showing an example of a phototypesetting machine. 11 ... Spot pattern 21 ... Spot pattern 31 ... Spot pattern 41 ... Spot pattern 42 ... Translucent dot 51 ... Spot pattern 61 ... Spot pattern 62 ... Opening 74 ... Dial 79 ... Photosensitive material.

Claims (2)

[Claims] 1. An optical drawing apparatus for irradiating a spot pattern with light to project a light spot on a photosensitive member and continuously moving the light spot and the photosensitive member to draw a ruled line, wherein the spot pattern is transparent. An optical drawing device using a light beam, characterized in that it has a structure in which light-like openings are spirally arranged in a predetermined circular region. 2. The optical drawing apparatus according to claim 1, wherein the spot pattern is formed by arranging dots or continuous openings in a circular area.