Abstract: A projection lens system that projects projected light from a light modulator to a screen, comprising in order from a screen side: a first lens group with a negative refractive power; a second lens group with a positive refractive power; and a third lens group with a positive refractive power is provided. The third lens group includes at least two cemented lenses and a lens with a positive refractive power positioned on an opposite side of the cemented lenses to the screen. Since the projection lens system achieves a sufficiently high correcting performance for various aberrations using fewer aspherical lenses, it is suitable lens system for a rear projector with high image quality.

Abstract: A device has a plurality of linear sensors which are arranged for at least one coordinate axis and detect the beam spot. The levels of detected data are measured by a sensor controller, and the measured levels are compared. Based on the comparison result, the detection result of one of the plurality of linear sensors is selected. A coordinate computation unit outputs a coordinate value corresponding to the beam spot on the basis of the selected detection result. The light-receiving areas of the linear sensors have an overlapping portion.

Abstract: A device has a projection type image display unit which has a projection lens and generates a coordinate input screen, and linear sensors for sensing an image of a beam spot, and computes a coordinate value corresponding to the beam spot on the basis of information obtained by the projection type image display unit and the output signals from the linear sensors. This beam spot is generated by irradiating the predetermined position on the coordinate input screen with light coming from a pointing tool, or corresponds to a light-emitting portion provided to the distal end of the pointing tool located near the coordinate input screen.

Abstract: A photodetector includes a photoreceiving unit which receives a light beam that blinks a plurality of times per detection period and coverts the received light beam into an output signal. A signal processing and control unit controls the photoreceiving unit so that the output signal increases in strength as a blinking cycle count increases in each detection period.

Abstract: A device has a light-receiving element for receiving light coming from a pointing tool, and a plurality of linear sensors for sensing a beam spot. A controller discriminates if a first signal output from the light-receiving element and a second signal output from the linear sensors are synchronized. A coordinate computation unit outputs a coordinate value corresponding to the beam spot on the basis of the discrimination result.

Abstract: A plurality of linear sensors (20Xa, 20Xb, 20Ya, 20Yb) sense a beam spot and the results of sensing the beam spot are corrected. The corrected items of data are concatenated and coordinates corresponding to the beam spot are calculated by a coordinate calculation unit (32) based upon the concatenated data. Light-receptive areas of the linear sensors (20Xa, 20Xb, 20Ya, 20Yb) have mutually overlapping portions.

Abstract: A first cylindrical lens and a first linear sensor are constructed on the X axis, a second cylindrical lens and a second linear sensor are constructed on the Y axis, the X and Y axes are orthogonal, and the image width of a beam spot formed by each of the first and second cylindrical lenses is larger than each pixel of the corresponding first and second linear sensors.

Abstract: A cap covering a light-emitting element attached to the distal end of an indicator is held by a sliding member, and is slidably attached axially along the indicator. By pressing/separating the cap against/from a coordinate input surface, a tact switch operates interlockingly with the cap to switch driving control of the light-emitting element. For example, the light-emitting element is driven by pressing the cap, and driving of the light-emitting element is stopped by separating the cap. Since the cap covers the light-emitting element, the light-emitting element can be prevented from being worn and scratched. Driving control of the light-emitting element need not be additionally switched, resulting in high operability.

Abstract: In inputting coordinate data on an information display screen from a pointing device, a signal is transmitted from the pointing device to a light-receiving element of a fixed unit by infrared light, a signal representing the tilt of the pointing device itself is received by light-receiving elements of the pointing device by infrared light, and on the basis of the signal, coordinate data is calculated by the coordinate calculation section of the pointing device. In this case, the pointing device can obtain the relative tilt of the pointing device itself as coordinate data by the interaction with respect to the fixed unit.

Abstract: In a reproducing apparatus, an equalizing system including a plurality of elements to be controlled is arranged to have its equalizing characteristic simply variable by controlling, with a single parameter, the plurality of elements to be controlled. Further, circuit characteristics of the equalizing system which are based on resonance frequencies and quality factors (Q) are controlled by controlling the resonance frequencies and the quality factors (Q) through the control performed with the single parameter over the plurality of elements to be controlled.

Abstract: A photodetector includes a photoreceiving unit which receives a light beam that blinks a plurality of times per detection period and coverts the received light beam into an output signal. A signal processing and control unit controls the photoreceiving unit so that the output signal increases in strength as a blinking cycle count increases in each detection period.

Abstract: In a reproducing apparatus, an equalizing system including a plurality of elements to be controlled is arranged to have its equalizing characteristic simply variable by controlling, with a single parameter, the plurality of elements to be controlled. Further, circuit characteristics of the equalizing system which are based on resonance frequencies and quality factors (Q) are controlled by controlling the resonance frequencies and the quality factors (Q) through the control performed with the single parameter over the plurality of elements to be controlled.

Abstract: In inputting coordinate data on an information display screen from a pointing device, a signal is transmitted from the pointing device to a light-receiving element of a fixed unit by infrared light, a signal representing the tilt of the pointing device itself is received by light-receiving elements of the pointing device by infrared light, and on the basis of the signal, coordinate data is calculated by the coordinate calculation section of the pointing device. In this case, the pointing device can obtain the relative tilt of the pointing device itself as coordinate data by the interaction with respect to the fixed unit.

Abstract: A coordinate input apparatus has a region with optical characteristics for transmitting light from a pointing tool, thereby preventing reflection of external light in the visible light range from the input surface of a coordinate input screen.

Abstract: A projection-type image display apparatus includes a projected-image generating device arranged to display a projected image by projecting image light onto a projection plane, a detector for detecting a positional deviation of the projected image from a predetermined position on the projection plane, and a corrector for correcting the positional deviation of the projected image according to a result of detection by the detector.