A light-source optical system includes a wavelength converter on which light of first color is incident, the wavelength converter converting at least a part of the light of first color into light of second color different from the light of first color, a first optical system disposed upstream from the wavelength converter on an optical path of the light of first color, the first optical system including optical elements, a reflection plane disposed downstream from the first optical system on the optical path, and a second optical system disposed downstream from the reflection plane on the optical path. The reflection plane reflects one of the light of first color and the light of second color, and a conditional expression “0<ΔL/D<0.2” is satisfied.

An optical system includes a light source configured to emit irradiation light, an optical modulation element having a plurality of reflection planes by which an incident light is reflected in a different direction, and an optical element having an interface through which the irradiation light emitted from the light source is emitted to the optical modulation element as the incident light and a first exit light reflected by the optical modulation element in a first direction is guided to a projection surface. Each one of the plurality of reflection planes is inclined with reference to a surface of the optical modulation element to reflect the incident light as the first exit light, and the surface of the optical modulation element is inclined with reference to the interface.

A prism block includes a first prism having first, second and third surfaces, a second prism having a fourth surface parallel to the first surface, a fifth surface facing the second surface, and a sixth surface, a third prism having seventh and eight surfaces respectively facing the second and fifth surfaces, and an optical path separation coating disposed between the fifth and eighth surfaces. Illumination light incident on the third surface is reflected by the second surface, and is emitted from the first surface. Projection light incident on the first surface is emitted from the fourth surface. Imaging light incident on the fourth surface is reflected by the optical path separation coating, and is emitted from the sixth surface. A projection axis plane including optical paths of the illumination light and the projection light, and an imaging axis plane including an optical path of the imaging light intersect each other.

A projector including a light source, a first prism, a second prism and a digital micro-mirror device (DMD) is provided. The light source emits light. The first prism includes a first surface, a second surface and a third surface which are connected to each other around the perimeter thereof, and the illumination light enters the first prism through the first surface. The second prism has a fourth surface and a fifth surface which are connected to each other, and the fourth surface faces the second surface of the first prism. The DMD faces the third surface. The illumination light sequentially passes through the first surface, is reflected by the second surface, passes through the third surface, and reaches the DMD. The DMD converts the illumination light into image light, and the image light sequentially passes through the third surface, the second surface, the fourth surface and the fifth surface. In the first prism, a first included angle between the first surface and the third surface is more than or equal to 105 degrees.

A lighting device of the present disclosure includes a light source device and a reflective component. The reflective component reflects an illumination light incident from the light source device off the reflecting surface of the reflective component at incident angle α, and emits the illumination light reflected toward a display element at exit angle β. The reflecting surface of the reflective component is rotated with respect to two axes orthogonal to each other. 20 degrees≤|α−β|≤60 degrees is satisfied. Where, each of the incident angle α and the exit angle β is angle of the illumination light to a horizontal direction of the display element when the illumination light is incident on a front surface of the display element.

A parameter adjusting method is applied to a projector having an ambient light sensor, a database and a digital micromirror device. The parameter adjusting method includes analyzing a detection signal generated by the ambient light sensor to acquire an environmental light datum, comparing the environmental light datum with a lookup table of the database to compute at least one compensation parameter, and adjusting an amount of reflection light generated by the digital micromirror device in accordance with the at least one compensation parameter for controlling the projector to output a calibrated projection image in response to compensation of the environmental light datum.

Implementations of a compressive light field projection system are disclosed herein. In one embodiment, the compressive light field projection system utilizes a pair of light modulators, such as digital micromirror devices (DMDs), that interact to produce a light field. The light field is then projected via a projection lens onto a screen, which may be an angle expanding projection screen that includes a Fresnel lens for straightening the views of the light field and either a double lenticular array of Keplerian lens pairs or a single lenticular, for increasing the field of view. In addition, compression techniques are disclosed for generating patterns to place on the pair of light modulators so as to reduce the number of frames needed to recreate a light field.

A display apparatus of the present disclosure includes: a first optical system that generates illumination light whose light emitting luminance is variable; a light modulation unit that transmits the illumination light from the first optical system and whose transmissivity is variable; a second optical system that includes a light modulation device and optically modulates the illumination light from the first optical system by using a pulse width modulation technology, the illumination light having passed through the light modulation unit; and a control unit that controls the light emitting luminance of the illumination light from the first optical system and the transmissivity of the light modulation unit in any combination.

A multi-axis gimbal actuator includes a first tilt frame tiltably coupled to a second tilt frame. The second frame is tiltably coupled to a reference frame. The first tilt frame is offset from the second tilt frame and approximately parallel to the second tilt frame while in a neutral position. An optical element is mounted on the first tilt frame.

A semiconductor device and the like with low power consumption are provided. In a semiconductor device including an electrostatic actuator group, an OS transistor and a capacitor are provided in each electrostatic actuator, and a power supply voltage supplied from the outside is boosted in each electrostatic actuator. The use of the OS transistor can retain the boosted voltage for a long period even after the supply of the power supply voltage is stopped. The use of the OS transistor can miniaturize the capacitor.