Abstract: The optical element comprises a first diffraction structure for generating three beams by diffracting light from a light source and a second diffraction structure that exhibits structural birefringence for a prescribed polarized light returning to the light source. The first diffraction structure is formed on a first face of a translucent optical base material and the second diffraction structure is formed on a second face of the optical base material. The optical base material, the first diffraction structure and the second diffraction structure are formed of a single material.

Abstract: It is to provide an optical element, an optical pickup device, and an optical information recording and/or reproducing apparatus, which can decrease the offset effectively and detect fine tracking error signals even when there is a difference between the light quantities of the two sub-beams. The first to fifth periodic structures enable generation of three beams that can provide an ideal-shaped waveform of the sum signal of two sub push-pull signals which are detected respectively from two sub-beams, whether or not there is a difference between the light quantities of the two sub-beams.

Abstract: The optical element comprises a first diffraction structure for generating three beams by diffracting light from a light source and a second diffraction structure that exhibits structural birefringence for a prescribed polarized light returning to the light source. The first diffraction structure is formed on a first face of a translucent optical base material and the second diffraction structure is formed on a second face of the optical base material. The optical base material, the first diffraction structure and the second diffraction structure are formed of a single material.

Abstract: A liquid crystal display panel of the active matrix type which uses, as switching elements, non-linear resistance elements that exhibit asymmetric non-linear characteristics depending upon the polarity of the applied voltage, without causing flickering or scorching of the display. The amplitude of the data signal is changed depending on the characteristics of the non-linear resistance element, such as a2 in the positive-side field and b2 in the negative-side field, and the panel is driven in a manner that the transmission factor modulation range is the same in the positive-side field and in the negative-side field. In the gradation display based on the pulse width modulation, the pulse width is adjusted depending on the non-linear characteristics in the positive-side field and in the negative-side field, such that the relationship between the degree of gradation and the transmission factor is the same on the positive side and on the negative side.