JPS60254125A - Lighting device for slit exposure - Google Patents

Abstract

PURPOSE:To uniform the illuminance at a part to be illuminated by irradiating the objective part with direct light from a tubular light source and with reflected light from a columnar main reflecting mirror, upper reflecting mirror, lower reflecting mirror, and rear reflecting mirror, and adding reflected light from a corrugated auxiliary reflecting mirror. CONSTITUTION:The part 24 to be irradiated is irradiated lightly from the tubular light source 21 having light emission parts 21' dispered in series and also irradiated with reflected light from the upper reflecting mirror 22a, lower reflecting mirror 22b, and rear reflecting mirror 22c. Further, the corrugated reflecting mirror 23 related to the positions of the light emitting parts 21' is provided as the auxiliary reflecting mirror. Consequently, reflected light beams from the respective reflecting mirrors are put together to uniform the illuminance at the irradiated part 24.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a slit exposure illumination device for efficiently illuminating a portion to be illuminated in a slit exposure copying machine.

Conventional Structure and Problems In general, the illumination optical system of a slit exposure copying machine consists of a tubular light source 1, a columnar main reflecting mirror 2 (upper reflecting mirror 2a), as shown in FIG.
, a lower reflecting mirror 2b, and a back reflecting mirror 2C. )
A slit exposure illumination device consisting of a slit and an auxiliary reflecting mirror 3 is provided, and an original on a stage glass 4 is projected onto a photoreceptor 7 through a slit 6 by a projection lens 5. Among these, in the slit exposure illumination device, first, the illuminated area 8 corresponding to the slit 6 is placed on the stage glass 4.
Of the light emitted from the tubular light source 1 disposed on one side of the optical path leading from the projection lens 5 to the projection lens 5, the light reflected by the upper reflecting mirror 2a on the stage glass 4 side is reflected by the upper reflecting mirror 2a across the optical path of the projection lens 5. The light is reflected by an auxiliary reflecting mirror 3 located on the opposite side of 2a and illuminates the illuminated portion 8. On the other hand, the reflected light from the lower reflecting mirror 2b located on the opposite side of the state gauge 2240 from the tubular light source 1 directly illuminates the illuminated portion 8.

The illuminated portion 8 also receives direct light from the tubular light source 1. In this way, the illuminated area 8 is often illuminated from both sides of the optical path of the projection optical system.

In the above slit exposure illumination device, the long axis direction of the tubular light source 1 is X, the illuminance of the illuminated part 8 is E, and when the illuminated part 8 is focused, a periodic illuminance distribution as shown in FIG. 6 is obtained. Become. This is because the tubular light source 1 is composed of a filament support e and a filament 10, as shown in FIG.

As a method to reduce the amplitude of this illuminance distribution, (+L)
The tubular light source 1 is frosted so that the entire surface of the tubular light source 1 emits light. (b) As shown in FIG. 8, a plurality of focal points are provided to the illuminated portion 8. (cl (a) above.

■) are used in combination.

However, in the case of method (a), the emitted light from the filament 1° hits the bulb 11 and is scattered, returning to the inside of the pulp and being absorbed by the pulp 11 itself, reducing efficiency. In addition, in the case of (bl), there was a problem in that the illumination efficiency for the illuminated section 8 decreased, such as the light collection efficiency decreased due to the creation of a plurality of focal points on the illuminated section 8.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to provide a slit exposure illumination device in which the illumination distribution of the illuminated area is uniform by providing a corrugated shape in the length direction of the auxiliary reflecting mirror. .

Structure of the Invention In order to achieve the above object, the present invention includes a tubular light source located on one side of the optical path from the illuminated part to the projection lens, a columnar main reflecting mirror that partially surrounds the tubular light source, and a columnar main reflector that sandwiches the optical path. In a slit exposure illumination device consisting of a reflecting mirror and an auxiliary reflecting mirror located on the opposite side, the light from the tubular light source is reflected by the columnar main reflecting mirror and the auxiliary reflecting mirror and focuses on the illuminated area. This is a slit exposure illumination device in which the auxiliary reflecting mirror has a corrugated shape in the longitudinal direction so as to be located in the middle of the light reflected by the mirror and focused on the illuminated area.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

The slit exposure illumination device is composed of a tubular light source 21, a columnar main reflecting mirror 22 partially surrounding the tubular light source, an auxiliary reflecting mirror 23 having a corrugated plate shape in the length direction of the reflecting mirror, and a stage glass 24. be done. Further, the columnar main reflecting mirror 22 includes an upper reflecting mirror 22, a lower reflecting mirror 22b, and a back reflecting mirror 220.

The operation of the slit exposure illumination device of this embodiment configured as described above will be described below.

The light reflected from the tubular light source 21 by the lower reflecting mirror 22b and irradiating the stage glass 24 has a periodic illuminance distribution as shown in FIG. 2B. In addition, the light directly irradiating the stage glass 24 from the tubular light source 21 is
As shown in FIG. 2, the illuminance is lower than that shown in a of FIG. 2, and the stage glass 24 is irradiated with a periodic illuminance distribution with a phase similar to that of the turtle in FIG. On the other hand, it is reflected by the upper reflector 22a and the auxiliary reflector 23, and the stage glass 24 is irradiated to set the surface of the oil (Fig. 3). do. In this case, as shown in FIG. 3, if the corrugated plate-shaped convex portions p and p' points and the binding concave portions are Q and Q' points, the p and p' points are placed corresponding to the center of each segment. Also, depending on the difference in length of each segment, p q
By changing the lengths of , P/Q/, an illuminance distribution in which the periodic phase is shifted by 18° as shown in a in FIG. 2 can be obtained. At this time, by making the illuminance value b in Fig. 2 the same value when the illuminance obtained by adding the tortoise and C in Fig. 2 is shifted by 18 degrees, the stage glass 2
The overall illuminance distribution of the light irradiated on the light source 4 becomes uniform as shown in d in FIG. In addition, the illuminance value h + b
In order to make them the same, the angle θ4 created by the upper reflector 221L and the tubular light source 21 shown in FIG.
This can be realized by making the columnar main reflecting mirror 22 equal to the sum of the angle θb produced by the tubular light source 21 and the angle θC produced by the illuminated portion 8 and the tubular light source 21.

Effects of the Invention As is clear from the description of the above embodiments, the slit exposure illumination device of the present invention provides a corrugated shape to the auxiliary reflecting mirror of the optical system, thereby adjusting the periodic illuminance distribution from the lower reflecting mirror. However, it is possible to create a periodic illuminance distribution with a phase shift of 1800 degrees, and the overall light of the irradiated area is one in which the periodic illuminance distribution has been eliminated, making it possible to uniformly illuminate the irradiated area. can.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the optical system of a slit exposure illumination device having the structure of the present invention, FIG. 2 is an explanatory diagram of light distribution characteristics by the optical system of the slit exposure illumination device of the present invention, and FIGS. Fig. 4 is an optical explanatory diagram thereof, Fig. 6 is an explanatory diagram of a conventional slit exposure illumination device and its related optical system, Fig. 6 is an illuminance distribution diagram of the irradiated area in the conventional slit exposure illumination device, and Fig. 7 is an illustration of the illuminance distribution of the irradiated area in the conventional slit exposure illumination device. Fig. 8 is a structural diagram of a tubular non-rogen light bulb used in a slit exposure illumination device.
FIG. 2 is an explanatory diagram of an optical system in a case where a plurality of focal points are provided on an irradiated part. 21... Tubular light source, 22... Columnar main reflecting mirror, 22a... Upper reflecting mirror, 22b...
・Lower reflector, 220... Rear reflector, 23・
...Auxiliary reflector, 24...Stage glass, a...Light distribution characteristic curve of light reflected by the lower reflector and focused on the irradiated area, b... ...Light distribution characteristic curve of light reflected by the auxiliary reflector and focused on the irradiated area, C...
...Light distribution characteristic curve of light irradiated directly from the tubular light source to the irradiated part, d...Light distribution characteristic curve of the irradiated part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 'Z2c Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A tubular light source located on one side of the optical path from the illuminated part to the projection lens, a columnar main reflecting mirror partially surrounding the tubular light source, and an auxiliary reflecting mirror located on the opposite side of the columnar main reflecting mirror across the optical path. In the slit exposure illumination device, the light from the tubular light source is reflected by the columnar main reflector and the auxiliary reflector and focused on the illuminated area, and the light reflected by the columnar main reflector and focused on the illuminated area. A corrugated plate shape is provided in the longitudinal direction of the auxiliary reflecting mirror so that it is located in the middle of the slit g-light illumination device.