Abstract: A wafer grinding method includes grinding a central portion of a wafer by using a plurality of abrasive members annularly arranged so as to form a circular ring, thereby forming a circular recess at the central portion of the wafer and simultaneously forming an annular projection around the circular recess, recognizing a height of a grinding unit after grinding the center by using a height recognizing unit and next storing the height recognized above, and grinding an upper surface of the annular projection to a predetermined value for a height of the annular projection previously set by a setting section as a grinding end height where the grinding of the annular projection by the grinding unit is ended.

Abstract: A wafer grinding method includes grinding a central portion of a wafer by using a plurality of abrasive members annularly arranged so as to form a circular ring, thereby forming a circular recess at the central portion of the wafer and simultaneously forming an annular projection around the circular recess, recognizing a height of a grinding unit after grinding the center by using a height recognizing unit and next storing the height recognized above, and grinding an upper surface of the annular projection to a predetermined value for a height of the annular projection previously set by a setting section as a grinding end height where the grinding of the annular projection by the grinding unit is ended.

Abstract: A method of processing a wafer having on a face side thereof a device area with a plurality of devices formed therein and an outer circumferential excess area surrounding the device area includes a grinding step for grinding a reverse side of the wafer corresponding to the device area with a grinding wheel that is smaller in diameter than the wafer, thereby forming a first portion corresponding to the device area and an annular second portion surrounding the first portion, the annular second portion being thicker and more protrusive toward a reverse side thereof than the first portion. In the grinding step, the grinding wheel and the wafer are moved relatively to each other so that the angle formed between the reverse side of the first portion and an inner side surface of the annular second portion is larger than 45° and smaller than 75°.

Abstract: A method of processing a wafer having on a face side thereof a device area with a plurality of devices formed therein and an outer circumferential excess area surrounding the device area includes a grinding step for grinding a reverse side of the wafer corresponding to the device area with a grinding wheel that is smaller in diameter than the wafer, thereby forming a first portion corresponding to the device area and an annular second portion surrounding the first portion, the annular second portion being thicker and more protrusive toward a reverse side thereof than the first portion. In the grinding step, the grinding wheel and the wafer are moved relatively to each other so that the angle formed between the reverse side of the first portion and an inner side surface of the annular second portion is larger than 45° and smaller than 75°.

Abstract: A liquid crystal display apparatus is disclosed which can prevent occurrence of flicker regardless of display modes. The apparatus includes a liquid crystal modulation element which includes a liquid crystal layer between a first electrode and a second electrode, a controller which controls a potential difference to be applied between the first and second electrodes. The apparatus operates in first and second modes, which are different in the light amount entering the element. A memory stores first information for the first mode and second information for the second mode as controlling information on a potential difference between the electrodes for suppressing flicker within a certain range. The controller controls the potential difference between the electrodes based on the first information when the first mode is set and controls the potential difference between the electrodes based on the second information when the second mode is set.

Abstract: A liquid crystal display device includes a liquid crystal modulation element including a first electrode, a second electrode, and a liquid crystal layer, a potential difference providing unit that provides a potential difference between the first electrode and the second electrode, and an illumination optical system that illuminates the liquid crystal modulation element by using light from a light source. The liquid crystal display device includes a charge adjusting mode for reducing the intensity of an electric field generated by electric charge stored between the liquid crystal layer and at least one of the first electrode and the second electrode.

Abstract: At least one exemplary embodiment is directed to an image display device which includes a first TN liquid crystal modulator for modulating the polarization state of first colored light; a second TN liquid crystal modulator for modulating the polarization state of second colored light; a third TN liquid crystal modulator for modulating the polarization state of third colored light; and an optical system for synthesizing the image light emitted from the three liquid crystal modulators; where a first voltage is applied to the first liquid crystal modulator for providing the first colored light with about half-wavelength phase difference; second voltage higher than the first voltage is applied to the second liquid crystal modulator for providing the second colored light with about half-wavelength phase difference; and third voltage higher than the second voltage is applied to the third liquid crystal modulator for providing the third colored light with about half-wavelength phase difference.

Abstract: A liquid crystal display apparatus is disclosed which can prevent occurrence of flicker for a long time. The apparatus comprises a liquid crystal modulation element which includes a first electrode, a second electrode made of a material different from that of the first electrode, a liquid crystal layer disposed between the first and second electrodes, a first alignment film disposed between the first electrode and the liquid crystal layer, and a second alignment film disposed between the second electrode and the liquid crystal layer. The apparatus also comprises a controller which changes at least one of the potential to be applied to the first electrode and the central potential of the potential to be applied to the second electrode, which periodically changes between positive and negative with respect to the central potential, such that flicker is suppressed within a certain range.

Abstract: The invention provides a laser etching method for optical ablation working by irradiating a work article formed of an inorganic material with a laser light from a laser oscillator capable of emitting in succession light pulses of a large energy density in space and time with a pulse radiation time not exceeding 1 picosecond, wherein, in laser etching of the work article formed of the inorganic material by irradiation thereof with the laser light from the laser oscillator with a predetermined pattern and with a predetermined energy density, there is utilized means for preventing deposition of a work by-product around the etching position.

Abstract: An optical system is disclosed which is capable of improving of its contrast characteristic and displaying of images which have a brightness according to the brightness of the use environment. The optical system comprises an optical integrator which divides and recombines the illumination luminous flux in a first axis direction and a light intensity distribution converter which converts the light intensity distribution of the illumination luminous flux in a second axis direction. The optical system further comprises a luminous flux limiting unit which has an aperture. The size of the aperture is changeable in the second axis direction and unchangeable in the first axis direction.

Abstract: At least one exemplary embodiment is directed to an image display device which includes a first TN liquid crystal modulator for modulating the polarization state of first colored light; a second TN liquid crystal modulator for modulating the polarization state of second colored light; a third TN liquid crystal modulator for modulating the polarization state of third colored light; and an optical system for synthesizing the image light emitted from the three liquid crystal modulators; where a first voltage is applied to the first liquid crystal modulator for providing the first colored light with about half-wavelength phase difference; second voltage higher than the first voltage is applied to the second liquid crystal modulator for providing the second colored light with about half-wavelength phase difference; and third voltage higher than the second voltage is applied to the third liquid crystal modulator for providing the third colored light with about half-wavelength phase difference.

Abstract: At least one exemplary embodiment is directed to an image display device which includes: a first TN liquid crystal modulator for modulating the polarization state of first colored light; a second TN liquid crystal modulator for modulating the polarization state of second colored light; a third TN liquid crystal modulator for modulating the polarization state of third colored light; and an optical system for synthesizing the image light emitted from the three liquid crystal modulators; where a first voltage is applied to the first liquid crystal modulator for providing the first colored light with about half-wavelength phase difference; second voltage higher than the first voltage is applied to the second liquid crystal modulator for providing the second colored light with about half-wavelength phase difference; and third voltage higher than the second voltage is applied to the third liquid crystal modulator for providing the third colored light with about half-wavelength phase difference.

Abstract: An illumination optical system which can use light from a light source with high efficiency and can provide an illumination luminous flux with highly uniform illuminance, is disclosed. The illumination optical system illuminates an illumination surface with a generally telecentric illumination luminous flux. In light intensity distribution of illumination light on the illumination surface changing depending on a deviation angle of an incident ray with respect to a normal to the illumination surface, the illumination optical system operates the illumination luminous flux such that a ratio of angle widths at which light intensity reaches half of a peak value in each of two axis directions orthogonal to each other on the illumination surface is an aspect ratio of 2:1.

Abstract: A liquid crystal display apparatus is disclosed which can prevent occurrence of flicker for a long time. The apparatus comprises a liquid crystal modulation element which includes a first electrode, a second electrode made of a material different from that of the first electrode, a liquid crystal layer disposed between the first and second electrodes, a first alignment film disposed between the first electrode and the liquid crystal layer, and a second alignment film disposed between the second electrode and the liquid crystal layer. The apparatus also comprises a controller which changes at least one of the potential to be applied to the first electrode and the central potential of the potential to be applied to the second electrode, which periodically changes between positive and negative with respect to the central potential, such that flicker is suppressed within a certain range.

Abstract: A liquid crystal display apparatus is disclosed which can prevent occurrence of flicker regardless of display modes. The apparatus includes a liquid crystal modulation element which includes a liquid crystal layer between a first electrode and a second electrode, a controller which controls a potential difference to be applied between the first and second electrodes. The apparatus operates in first and second modes, which are different in the light amount entering the element. A memory stores first information for the first mode and second information for the second mode as controlling information on a potential difference between the electrodes for suppressing flicker within a certain range. The controller controls the potential difference between the electrodes based on the first information when the first mode is set and controls the potential difference between the electrodes based on the second information when the second mode is set.

Abstract: A liquid crystal display device includes a liquid crystal modulation element including a first electrode, a second electrode, and a liquid crystal layer, a potential difference providing unit that provides a potential difference between the first electrode and the second electrode, and an illumination optical system that illuminates the liquid crystal modulation element by using light from a light source. The liquid crystal display device includes a charge adjusting mode for reducing the intensity of an electric field generated by electric charge stored between the liquid crystal layer and at least one of the first electrode and the second electrode.

Abstract: A liquid crystal display includes a liquid crystal modulator that includes first and second electrodes, and a liquid crystal layer between the first and second electrodes, and a controller for changing at least one of potential provided to the first electrode and central potential of the potential provided to the second electrode so that flicker falls within a specific range after power is turned on and before a charging phenomenon in the liquid crystal modulator is stabilized.

Abstract: An illumination optical system is disclosed, which provides a luminous flux with a small incident angle on an illumination surface in one axis direction on a section of the luminous flux. The illumination optical system can suppress a reduction in light amount by a mask provided for a polarization conversion element. The illumination optical system has a light source and an optical integrator. The optical integrator uses a lens array to perform splitting of a luminous flux from the light source. The illumination optical system has the polarization conversion element including a polarization beam splitter array, a plurality of ½ wave plates, and a mask. The light source is a discharge gas exciting arc tube of a DC drive type.

Abstract: The invention provides a laser etching method for optical ablation working by irradiating a work article formed of an inorganic material with a laser light from a laser oscillator capable of emitting in succession light pulses of a large energy density in space and time with a pulse radiation time not exceeding 1 picosecond, wherein, in laser etching of the work article formed of the inorganic material by irradiation thereof with the laser light from the laser oscillator with a predetermined pattern and with a predetermined energy density, there is utilized means for preventing deposition of a work by-product around the etching position.

Abstract: The invention provides a laser etching method for optical ablation working by irradiating a work article formed of an inorganic material with a laser light from a laser oscillator capable of emitting in succession light pulses of a large energy density in space and time with a pulse radiation time not exceeding 1 picosecond, wherein, in laser etching of the work article formed of the inorganic material by irradiation thereof with the laser light from the laser oscillator with a predetermined pattern and with a predetermined energy density, there is utilized means for preventing deposition of a work by-product around the etching position.