Abstract: An exposure apparatus for use in fabricating a printed circuit board. A thermally-written liquid-crystal light valve is provided in which a pattern is formed by opaque portions and transparent portions. A writing optical system directs a heating spot light onto the light valve. The light valve and/or the heating spot light is movable, relative to the other. A projecting optical system is arranged which transmits a luminous flux emitted from a light source, through a liquid-crystal layer within the liquid-crystal light valve. The projecting optical system illuminates a subject with the transmitted luminous flux.

Abstract: An exposure apparatus for use in fabricating a printed circuit board. A thermally-written liquid-crystal light valve is provided in which a pattern is formed by opaque portions and transparent portions. A writing optical system directs a heating spot light onto the light valve. The light valve and/or the heating spot light is movable, relative to the other. A projecting optical system is arranged which transmits a luminous flux emitted from a light source, through a liquid-crystal layer within the liquid-crystal light valve. The projecting optical system illuminates a subject with the transmitted luminous flux.

Abstract: An apparatus for correcting a scranning beam produced by a polygonal mirror tilting in small surface segments in each mirror surface segment caused by uneven mirror surfaces of the polygonal mirror. Data indicative of the amount of tilting in each of the surface segments is stored in a memory, which is addressed by a data signal indicative of the present scanning position of the polygonal mirror. Output data from the memory is applied to an acousto-optical modulator disposed in the beam path between the light source and the polygonal mirror.

Abstract: A monitor mechanism for use with a scanning optical apparatus in which the direction of polarization is utilized to separate a source laser light beam into a pattern drawing and a monitor beamlet and to synthesize them again into a single after passing through a scanning lens and beam deflector. The two beamlets can thus be controlled so as to project towards the deflector and scanning lens in the same direction, which is effective in reducing the offset between the pattern drawing and monitor beams that may occur on account of such factors as variations in lens performance.

Abstract: A drawing surface adjusting mechanism for use with a scanning pattern drawing apparatus capable of not only moving a drawing board in a vertical direction but also tilting it, whereby the chance of bringing the drawing surface within the depth of focus of a scanning lens is increased even if the drawing surface has waviness or other flaws within the width of a single storke of scanning.

Abstract: A table assembly that is simple in construction and which yet resists yawing in an effective way and is adapted for use with a scanning pattern drawing apparatus which involves continuous movements of the table. The inventive table assembly includes a master table that is slidable in one direction with respect to a fixed portion of the overall assembly and to which a drive force for causing the table to slide in the one direction is transmitted directly, and a working table that is slidable in the one direction with respect to the fixed portion and which is linked to the master table by connecting means having rigidity in the one direction and elasticity in a direction perpendicular to the one direction.

Abstract: A process for the production of a polyimide film having an increased adhesiveness which includes the steps of: evenly coating a surface treating solution which contains a heat-resistant surface treating agent of aminosilane type, epoxysilane type or titanate type in an amount not less than 0.5 wt. % on a surface of a solid film comprising an aromatic polymer composition which contains 100 parts by weight of an aromatic polyamic acid and 5-150 parts by weight of an organic polar solvent and heating the solid film having the coated surface treating solution at a temperature of 100.degree.-600.degree. C., to imidize the polyamic acid constituting the solid film as well as to dry the film.

Abstract: A dimensionally stable polyimide film and processes for the preparation thereof. The polyimide film is composed of an aromatic polyimide obtained from a solution of a polymer formed by polymerization of a biphenyl-tetracarboxylic acid and a phenylene diamine, wherein the average linear expansion coefficient of the polyimide film in the temperature range of from 50.degree. C. to 300.degree. C. is 0.1.times.10.sup.-5 to 2.5.times.10.sup.-5 cm/cm..degree.C., the ratio of the linear expansion coefficient in the machine direction of the film to the linear expansion coefficient in the transverse direction of the film is in the range of from 1/5 to 4, and the thermal dimension stability expressed by the ratio of the change of the size of the film at normal temperature after the heat treatment where the temperature is elevated to 400.degree. C. from normal temperature and the film is maintained at 400.degree. C. for 2 hours is less than 0.3%.