A power transmitting apparatus includes a power transmitting section that includes an input shaft section and an output shaft section and transmits drive force from the input shaft section to the output shaft section, a first detection section including a polarizing section that rotates when one of the input shaft section and the output shaft section rotates and has a polarization characteristic, a light source section that irradiates the polarizing section with light, and a light detection section that outputs a signal according to the intensity of the light from the polarizing section, a second detection section that outputs a signal according to the rotational state of the other one of the input shaft section and the output shaft section, and a determination section that determines the rotational state of the polarizing section based on the signal from the light detection section and the signal from the second detection section.

An encoder includes an optical scale including a scale portion that is constituted with a polarizer, a light emitting portion which emits light, an optical element unit which divides the light into first light and second light and makes the first and second lights incident onto the scale portion, and a light receiving portion which receives the first light and the second light from the scale unit and outputs a signal corresponding to intensities of the received first light and second light, and in which the first light and the second light overlap other within a plane of the scale portion.

Various embodiments relate to devices for measuring the state of devices and multi-stage rotary encoders as well as to associated sensors. In order to simplify the design of devices which can be read out electronically and multi-turn rotary encoders, according to some embodiments a device having at least one rotatable wheel, at least one light source and at least one polarization sensor is proposed, the wheel being at least partially transparent and polarization-maintaining, parts of the wheel being configured as pole filters, it being possible for light which exits the light source to be polarized by the pole filter and to be received by the polarization sensor.

An encoder includes an optical scale that has a phase difference plate, a light source section that irradiates the phase difference plate with light, and a light receiving section that receives the light from the phase difference plate, and outputs a signal corresponding to a received light intensity. The light emitted from the light source section is linearly polarized, and the light receiving section outputs a signal corresponding to a polarization state of the light from the phase difference plate.

A measurement scale device includes at least one scale marking, wherein the or each scale marking includes at least one periodic nanostructure that represents scale device information.

A rotary optical position encoder includes a source of a linear-polarized light beam, a polarization-sensitive detector, and a rotating retarder disposed for rotation between the source and the detector. The retarder is configured and operative to produce a polarized exit beam whose polarization state rotates at a rate greater than a rotation rate of the retarder, thereby for increased resolution over a similar encoder using a rotating polarizer element. In an example, when polarized light is incident upon a rotating half-wave retarder, the transmitted beam's polarization axis rotates at twice the rate of retarder rotation, resulting in an electrical detector output that varies four times per revolution. Resolution is improved accordingly, as a given detected increment at the output is produced by only one-half the physical rotation increment required for a simple polarizer.

A power transmitting apparatus includes a power transmitting section that includes an input shaft section and an output shaft section and transmits drive force from the input shaft section to the output shaft section, a first detection section including a polarizing section that rotates when one of the input shaft section and the output shaft section rotates and has a polarization characteristic, a light source section that irradiates the polarizing section with light, and a light detection section that outputs a signal according to the intensity of the light from the polarizing section, a second detection section that outputs a signal according to the rotational state of the other one of the input shaft section and the output shaft section, and a determination section that determines the rotational state of the polarizing section based on the signal from the light detection section and the signal from the second detection section.

A sleep mode system for an electronic device can include a light source, a sensor, and a light altering component. The light altering component can rotate with one device component, such as a laptop lid, while the light source and/or sensor remain stationary with another device component, such as a laptop base. A controller can determine the orientation angle of the light altering component based on the detected light, and can put the device into or remove the device from a sleep mode based on the angle, which can reflect an open state or closed state for the electronic device.

A moving platform roll sensor system comprises an ellipsometric detector capable of detecting a polarized beam within the detector's line-of-sight, and measuring the beam's polarization state, such that the polarization state indicates the rotational orientation of the moving platform with respect to a predefined coordinate system. The ellipsometric detector comprises a venetian blind component through which the polarized beam passes, arranged such that the intensity of the exiting beam varies with its incident angle with respect to the moving platform, a polarizing beamsplitter which splits the exiting beam into components having orthogonal circular polarizations, the relative intensities of which vary with the relative polarization vector of the beam, and first and second detectors which receive the first and second orthogonal circular components and generate respective outputs that vary with the intensities of their received components. The beamsplitter preferably comprises a quarter wave plate and a polarization grating.

A sleep mode system for an electronic device can include a light source, a sensor, and a light altering component. The light altering component can rotate with one device component, such as a laptop lid, while the light source and/or sensor remain stationary with another device component, such as a laptop base. A controller can determine the orientation angle of the light altering component based on the detected light, and can put the device into or remove the device from a sleep mode based on the angle, which can reflect an open state or closed state for the electronic device.