Abstract: An image displayed on a liquid crystal panel is projected on a projection surface by a projection lens such that the optical axis of the projection lens is perpendicular to the projection surface. An optical axis of a distance measurement light and an optical axis of a light receiving lens are each inclined a specified angle with respect to the optical axis of the projection lens to be not perpendicular to the projection surface so as to reduce noise caused by specularly reflected light that otherwise would be detected by the distance measurement unit when a highly reflective whiteboard is utilized as the projection surface. The distance measurement unit is formed by unitizing a light emitting element, a light emitting lens, the light receiving lens, and a light receiving element, and the distance measurement unit is held with the projection lens by a common holder.

Abstract: A distance measuring device includes a light emitter, a light detector, a clamp that outputs long-range side signal or clamp signal, a calculator that calculates the ratio between the short-range side signal and the signal output from the clamp and outputs a ratio signal, a light meter measuring the luminance of outside light, a threshold setter that sets up an infinity determination threshold value such that a lower luminance of the outside light corresponds to the longer range side as a threshold value; a converter that, when the output ratio signal is the signal corresponding to the short range side and is shorter than the infinity determination threshold value, converts the output ratio signal into a distance signal, and, if not, converts the output ratio signal into a distance signal having a fixed value.

Abstract: A distance measuring device includes light a projector for projecting a beam of light onto an object at a distance to be measured, a light detector for detecting the part of the beam of light reflected from the object and outputting an output signal, an integrator for discharging or charging an integration capacitor corresponding to the output signal to integrate the output signal, an analog-to-digital converter for converting the voltage of the integration capacitor after a predetermined number of repetitions of a distance measuring routine, and a detector for detecting the distance to the object based on the converted signal, wherein the number of repetitions of the distance measuring routine is set to saturate the integration capacitor through the repetition, when the object is located at a short range alarm position.

Abstract: A camera includes a light emitter, a light detector, a clamp circuit, a calculator for outputting an output ratio signal, a converter for converting the output ratio signal into a distance signal corresponding to the distance or a predetermined fixed value, a light meter for measuring the luminance of outside light, and an exposure control that, when the luminance of the outside light measured by the light meter is lower than a predetermined switchover luminance, controls the aperture of the camera lens to a released aperture value, and when higher than the predetermined switchover luminance, controls the aperture of the camera lens to increase corresponding to the luminance. A first auto-focus (AF) signal value corresponds to an infinity determination distance and a second AF signal value corresponds to the switchover luminance. The AF signal value, which corresponds to the shorter range, is set as an infinity determination threshold value.

Abstract: An image displayed on a liquid crystal panel is projected on a projection surface by a projection lens. An optical axis of a projection lens is perpendicular to the projection surface. However, alight emitting optical axis of a distance measurement light and an optical axis of a light receiving lens is inclined with respect to the optical axis of a projection lens, not to be perpendicular to the projection surface. A distance measurement unit is formed by unitizing a light emitting element, a light emitting lens, the light receiving lens, and a light receiving element, and the distance measurement unit is held with the projection lens by a common holder. Even if a surface like a whiteboard which has high reflectivity is used as the projection surface, high accuracy of the distance measurement is kept because diffused light from the light emitting lens, which is regularly reflected from the projection surface, is away from an effective photodetecting region of the light receiving element.

Abstract: A fuel cell is disposed inside a camera housing in the vicinity of a front panel, an upper panel, and a side panel in parallel with the respective panels. The invention provides broader cell area and adequate power can be supplied reliably.

Abstract: A transmitter has a tire condition sensor, a transmission circuit, a voltage sensor and an electricity control circuit. The tire condition sensor detects the condition of a tire. The voltage sensor detects a voltage of the battery. During a period from when the tire condition sensor detects the condition of the tire to when the transmission circuit starts transmitting the data, the electricity control circuit performs a transmission preparation process to gradually increase electricity supplied to the transmission circuit from a battery, thereby gradually increasing a radio wave output of the transmission circuit. If the value of the voltage detected by the voltage sensor is lowered to a lowest operation voltage of the transmitter during the transmission preparation process, the electricity control circuit limits the supply of electricity to the transmission circuit from the battery.

Abstract: A camera includes a light emitter, a light detector, a clamp circuit, a calculator for outputting an output ratio signal, a converter for converting the output ratio signal into a distance signal corresponding to the distance or a predetermined fixed value, a light meter for measuring the luminance of outside light, and an exposure control that, when the luminance of the outside light measured by the light meter is lower than a predetermined switchover luminance, controls the aperture of the camera lens to a released aperture value, and when higher than the predetermined switchover luminance, controls the aperture of the camera lens to increase corresponding to the luminance. A first auto-focus (AF) signal value corresponds to an infinity determination distance and a second AF signal value corresponds to the switchover luminance. The AF signal value, which corresponds to the shorter range, is set as an infinity determination threshold value.

Abstract: A distance measuring device includes light a projector for projecting a beam of light onto an object at a distance to be measured, a light detector for detecting the part of the beam of light reflected from the object and outputting an output signal, an integrator for discharging or charging an integration capacitor corresponding to the output signal to integrate the output signal, an analog-to-digital converter for converting the voltage of the integration capacitor after a predetermined number of repetitions of a distance measuring routine, and a detector for detecting the distance to the object based on the converted signal, wherein the number of repetitions of the distance measuring routine is set to saturate the integration capacitor through the repetition, when the object is located at a short range alarm position.

Abstract: A distance measuring device includes a light emitter, a light detector, a clamp that outputs long-range side signal or clamp signal, a calculator that calculates the ratio between the short-range side signal and the signal output from the clamp and outputs a ratio signal, a light meter measuring the luminance of outside light, a threshold setter that sets up an infinity determination threshold value such that a lower luminance of the outside light corresponds to the longer range side as a threshold value; a converter that, when the output ratio signal is the signal corresponding to the short range side and is shorter than the infinity determination threshold value, converts the output ratio signal into a distance signal, and, if not, converts the output ratio signal into a distance signal having a fixed value.

Abstract: Transmitters of a tire condition monitoring apparatus are provided in the tires at the left side of a vehicle and in the tires at the right side of the vehicle. Each transmitter has a pressure sensor and a temperature sensor for detecting conditions of the associated tire. Each transmitter wirelessly transmits data representing the condition of the associated tire detected by the sensors. Each transmitter has an acceleration detection sensor for detecting a direction of acceleration due to rotation of the associated tire. Based on data representing the direction of acceleration detected by the acceleration detection sensor, whether the transmitter is located in the tire at the left side or in the tire at the right side is identified.

Abstract: A transmitter has a tire condition sensor, a transmission circuit, a voltage sensor and an electricity control circuit. The tire condition sensor detects the condition of a tire. The voltage sensor detects a voltage of the battery. During a period from when the tire condition sensor detects the condition of the tire to when the transmission circuit starts transmitting the data, the electricity control circuit performs a transmission preparation process to gradually increase electricity supplied to the transmission circuit from a battery, thereby gradually increasing a radio wave output of the transmission circuit. If the value of the voltage detected by the voltage sensor is lowered to a lowest operation voltage of the transmitter during the transmission preparation process, the electricity control circuit limits the supply of electricity to the transmission circuit from the battery.

Abstract: In a rangefinder apparatus for projecting a light beam toward a target object a number of times; detecting light of the light beam reflected from the target object, and successively integrating output signals corresponding to the distance to the target object to carry out rangefinding; a voltage of an integrating capacitor in a rangefinding routine is detected, and the rangefinding routine is forcibly terminated if the voltage of the integrating capacitor is out of a preset range. Since the rangefinding routine is forcibly terminated if the voltage of the integrating capacitor in the rangefinding routine is outside of the preset range, malfunctions of a signal processing IC can be detected.

Abstract: Reflected light of each light beam projected toward an object at a distance to be measured is detected to provide a far signal and a near signal, and the far signal is compared with a preset clamp signal. The larger signal resulting from the comparison is outputted from a clamping circuit and a ratio of the output signal and the near signal is calculated to obtain an output ratio signal. Output ratio signals for light emissions from a light projecting unit are accumulated in an integration to produce an integral signal. The integral signal is transformed to a distance signal according to the distance by transformation equations selected based on whether the number of clamp signals outputted as output signals from the clamping circuit during the integration is larger than a set number.

Abstract: A rangefinder apparatus includes an infrared emitting diode projecting a light beam toward a target object several times; a position sensing device (PSD) for detecting light of the light beam reflected from the target object and outputting a signal corresponding to a distance to the target object; an auto-focus integrated circuit (AFIC) for processing the output signal of the PSD; and a CPU for outputting a control signal for the signal processing and a clamp setting signal for setting a clamp level to the AFIC, and a reset signal for resetting the AFIC to an initial state at an input terminal identical to that for the clamp setting signal. Since the clamp setting signal and the reset signal are fed to the same terminal, the cost of the signal processor can be reduced.

Abstract: A rangefinder apparatus includes an infrared emitting device (IRED) for projecting a light beam toward a target object; a position sensitive detector (PSD) for detecting light of the light beam reflected from the target object and outputting an output signal corresponding to a distance to the target object; an output circuit for charging an integrating capacitor according to the output signal of the PSD and an analog-to-digital (A/D) converter for converting a voltage of the integrating capacitor after an end of a rangefinding operation including a number of light-projecting actions by the IRED, light-detecting actions by the PSD, and integrating actions by the output circuit are repeated. Multiple rangefinding operations are carried out with a different number of repetitions, and the distance is determined according to respective values obtained by A/D conversions after the rangefinding operations. Consequently, conversion errors in A/D conversions are reduced, whereby the rangefinding accuracy is improved.

Abstract: A distance measuring apparatus projects light toward an object at a distance to be measured, detects reflected light at a position according to the distance to the object to output a position signal, generates a distance computation value based on the position signal, integrates the distance computation value with an integrating capacitor, detects the distance, based on distance data corresponding to the integrated result, charges the integrating capacitor with a constant current for a time, and calculates a voltage for the integrating capacitor. In the distance measuring apparatus, the distance to the object is determined, based on a correction voltage calculated in a ranging routine, a reference voltage of the integrating capacitor calculated before the ranging routine, and the distance data. The apparatus reduces ranging error due to a change in the capacitance of the integrating capacitor.

Abstract: A rangefinder apparatus comprises an IRED for projecting a light beam toward a target object; a PSD for receiving reflected light of the light beam projected to the target object and outputting an output signal corresponding to a distance to the target object; an output circuit for charging an integrating capacitor according to the output signal of the PSD; and converting means for A/D-converting a voltage of the integrating capacitor after an end of a rangefinding operation in which a predetermined number of light-projecting actions by the IRED, light-receiving actions by the PSD, and integrating actions by the output circuit are repeated; wherein a plurality of rangefinding operations are carried out with a different number of repetitions therein, and the distance is detected according to respective A/D-converted values obtained by A/D conversions after the rangefinding operations. Consequently, conversion errors in A/D conversions are reduced, whereby the rangefinding accuracy is improved.

Abstract: In a rangefinder apparatus for projecting a light beam toward a target object a plurality of times, receiving reflected light of the light beam projected to the target object, and successively integrating output signals corresponding to the distance to the target object, so as to carry out rangefinding; a voltage value of an integrating capacitor in a rangefinding routine is detected, and the rangefinding routine is forcibly terminated if the voltage value of integrating capacitor is out of a preset range. Since a rangefinding routine is forcibly terminated if the voltage value of integrating capacitor in the rangefinding routine is out of the preset range as such, malfunctions of a signal processing IC can be detected.

Abstract: A rangefinder apparatus comprises an IRED for projecting a light beam toward a target object a plurality of times; a PSD for receiving reflected light of the light beam projected to the target object and outputting a signal corresponding to the distance to the target object, an AFIC for processing the output signal of PSD; and a CPU for outputting a control signal for the signal processing and a clamp setting signal for setting a clamp level to the AFIC, and a reset signal for resetting the AFIC to an initial state to an input terminal identical to that for the clamp setting signal. Since the clamp setting signal and reset signal are fed to the same terminal, the cost of signal processing means can be cut down.