Optical recording system capable of changing the beam size

An optical recording system for recording an image on a recording medium by means of an optical beam that is deflected repeatedly in a horizontal scanning direction with a variable beam size, comprising:

• an optical beam source for producing an optical beam;
• first polarizing means provided in a path of said optical beam for rotating a polarizing plane of said optical beam in a first angular direction;
• shutter array means provided for receiving said optical beam from said first polarizing means, said shutter array means comprising:
• an electro-optic layer that shows the electro-optic effect on an optical beam that passes therethrough;
• a plurality of electrodes provided on said electro-optic layer, said electrodes being arranged to form electrode pairs each defining a shutter region therebetween for passing the optical beam that is incident to said shutter array means, each of said electrodes respectively forming each electrode pair inducing an electric field acting in a direction predetermined with respect to said horizontal scanning direction, upon application of a drive voltage therebetween, said electrode pairs being arranged such that each said shutter region is aligned in a vertical scanning direction that is perpendicular to said horizontal scanning direction;
• driving means connected to each of said electrode pairs for applying said drive voltage to said electrode pairs independently;
• biasing means connected to each of said electrode pairs for applying a d.c. bias voltage to the same;
• and
• control means for inverting the polarity of said d.c. bias voltage that is applied to the electrode pairs;
• second polarizing means provided in a path of the optical beam that has passed through the shutter array means for rotating the polarizing plane of the optical beam in a second, opposite angular direction with respect to said first polarizing means such that the polarizing plane of the optical beam that has passed through the second polarizing means crosses the polarizing plane of the optical beam that has passed through the first polarizing means substantially at a right angle;
• deflecting means provided in a path of the optical beam that has exited from said second polarizing means for deflecting the same repeatedly in said horizontal scanning direction;
• and
• focusing means for focusing the optical beam that has been deflected by the deflecting means on a recording medium.

An optical recording system for recording an image on a recording medium by means of an optical beam that is deflected repeatedly in a horizontal scanning direction, comprising:

• beam source means for producing an optical beam with a polarizing plane that intersects with the horizontal scanning direction by an angle of 45 degrees in a first angular direction;
• a first optical system provided in a path of the optical beam that has been produced by the beam source means for focusing the same at a first focal point to form an elongated optical beam having an elongated beam spot elongating in a vertical scanning direction that is perpendicular to said horizontal scanning direction;
• shutter array means provided in correspondence to a first focal point, said shutter array means comprising a plurality of apertures aligned in said vertical scanning direction and are activated independently for selectively passing the optical beam therethrough upon activation;
• the second optical system provided in a path of the optical beam that has passed through the shutter array means for focusing the same at a second location to form an elongated optical beam having an elongated beam stop elongating in said horizontal scanning direction;
• deflection means for deflecting the optical beam that has passed through the second optical system repeatedly in said horizontal scanning direction;
• a third optical system provided in a path of the optical beam that has been deflected by the deflection means for focusing the same on a recording surface of the recording medium;
• and
• a slit element provided on a path of the optical beam that has exited from the second optical system, said slit element carrying a slit extending in the horizontal scanning direction with a width set to eliminate diffraction beams that are formed when the optical beam has passed through the shutter array means for the diffraction higher than the first order.

A method for writing a pattern on an object by a focused optical beam one horizontal scanning line by one horizontal scanning line while controlling a passage of said optical beam through an electro-optic layer, said electro-optic layer being defined by a passage region for passing said optical beam and causing a rotation of a polarization plane of said optical beam upon application of a control voltage across said passage region, said method comprising the steps of:

• applying a d.c. bias voltage across said passage region with a predetermined polarity;
• inverting said polarity of the d.c. bias voltage periodically with a predetermined interval, wherein inverting the polarity of the d.c. bias voltage is achieved in each horizontal scanning interval that corresponds to the recording of one horizontal scanning line, said horizontal scanning interval including a recording interval for writing a pattern by the optical beam and a blanking interval wherein the optical beam is deactivated;
• applying a pulse signal in correspondence to a pattern element that forms an element of said pattern to be written on the object, such that said pulse signal has a polarity coincident to the polarity of the d.c. bias voltage signal when said pattern element is to be written and such that said pulse signal has a polarity opposite to the polarity of the d.c. bias voltage signal when said pattern element is not written on said object;
• detecting the number of times the electro-optic layer has passed the optical beam in each horizontal scanning interval;
• comparing said number of times thus detected that the electro-optic layer has passed the optical beam in the current horizontal scanning interval with the number of times the electro-optic layer has passed the optical beam in the horizontal scanning interval that immediately precedes the current horizontal scanning interval;
• and
• causing the electro-optic layer to be in a state for passing the optical beam in correspondence to the blanking interval of the current horizontal scanning interval for a number of times such that the number of times the electro-optic layer has taken the state for passing the optical beam is identical in each horizontal scanning interval.

A method for writing a pattern on an object by a focused optical beam one horizontal scanning line by one horizontal scanning line while controlling a passage of said optical beam through an electro-optic layer, said electro-optic layer being defined by a passage region for passing said optical beam and causing a rotation of a polarization plane of said optical beam upon application of a control voltage across said passage region, said method comprising the steps of:

• applying a d.c. bias voltage across said passage region with a predetermined polarity;
• inverting said polarity of the d.c. bias voltage periodically with a predetermined interval, wherein inverting the polarity of the d.c. bias voltage is achieved in each horizontal scanning interval that corresponds to the recording of one horizontal scanning line, said horizontal scanning interval including a recording interval for writing a pattern by the optical beam and a blanking interval wherein the optical beam is deactivated;
• applying a pulse signal in correspondence to a pattern element that forms an element of said pattern to be written on the object, such that said pulse signal has a polarity coincident to the polarity of the d.c. bias voltage signal when said pattern element is to be written and such that said pulse signal has a polarity opposite to the polarity of the d.c. bias voltage signal when said pattern element is not written on said object;
• detecting the number of times the electro-optic layer has passed the optical beam in each horizontal scanning interval;
• comparing said number of times thus detected that the electro-optic layer has passed the optical beam in the current horizontal scanning interval with a reference value;
• and
• causing the electro-optic layer to be in a state to pass the optical beam in correspondence to the blanking interval of the current horizontal scanning interval for a number of times such that the number of times the electro-optic layer has taken the state for passing the optical beam is identical in each horizontal scanning interval.