An image projection unit includes: a light source unit; a plurality of reflection-type image display elements; a plurality of total reflection prisms configured to guide lights of multiple colors emitted from the light source unit to the reflection-type image display elements and to emit the lights reflected from the reflection-type image display elements; a color synthesis prism configured to receive the lights emitted from the total reflection prisms, synthesize the lights, and emit the synthesized lights; a holding member fixed to the color synthesis prism and holding the reflection-type image display elements; and a base member supporting the color synthesis prism and the plurality of total reflection prisms

A display of various types of information on a subdisplay provided to a main body of a projector can be maintained even after supply of power source is stopped. According to a representative embodiment, included are: a power source connection unit connecting a power supply line for supplying, from outside, power used in a projection type image display apparatus; a nonvolatile display device provided separately from an image projection unit and displaying at least character information; and a processing unit displaying information on one or more predetermined items on the nonvolatile display device, and a state of displaying information on the nonvolatile display device is maintained even in a state where the power supply line is not connected to the power source connection unit.

A projection display device includes: a light source that emits a first and a second laser lights; a scanning drive mirror that reflects the first and the second laser lights, and uses the first and the second laser lights in scanning; a light diffusion unit that includes a predetermined region that allows the first laser light to be transmitted therethrough, and diffuses the first laser light; a light detection unit that detects the second laser light that passed the predetermined region; and a control unit that executes a process to detect the second laser light, and determines a state of the predetermined region on the basis of a detection value of the light detection unit. In a case where the control unit determines that a defect occurs in the predetermined region as the state, the control unit executes a process to stop displaying the projection.

A device for generating a display image on a composite glass pane is described. The device has: a composite glass pane with a first pane and a second pane, which are connected to each other via an intermediate layer that contains at least one luminescent pigment; a laser projector, which contains at least one laser and an optical system for deflecting a radiation of the laser, the radiation being directed within a region of the composite glass pane; a photodetector, which detects luminescent radiation of the luminescent pigment; and a control unit, which electronically connects the photodetector and the laser projector.

A projection type display apparatus includes: a semiconductor laser element that outputs laser light based on supply of current; a digital mirror device (DMD) that modulates the light output from the semiconductor laser element and emits the modulated light; a projection lens that projects the incident light via the DMD; a drive unit that drives the semiconductor laser element and includes a current detection unit for detecting the current value of the current flowing through the semiconductor laser element; and a controller that, when the current value detected by the current detection unit becomes greater than a first threshold, controls driving of the DMD so that the light output from the DMD will not be incident on the projection lens, and when the current value detected becomes greater than a second threshold greater than the first threshold, causes the drive unit to cut off the supply of current.

A light source which has a housing accommodating a light source lamp and having an exhaust port, a duct, and a fan are provided. The duct has an inlet facing the exhaust port, a branching part which branches air from the inlet, a duct part extending in a first direction orthogonal to an opening plane of the exhaust port, and a duct part extending in a second direction intersecting with the first direction. The fan is arranged in a position for sucking the air circulating through the duct part. The duct part has a plurality of sidewall parts, an opening, and a mesh.

In embodiments of translucent object presence and condition detection based on detected light intensity, a light is emitted and directed at a first edge of a translucent object along its thickness to pass through the translucent object, such as a lens. An intensity of the light is detected proximate an opposing, second edge of the translucent object. A presence and/or a condition of the translucent object can then be determined based on the detected intensity of the light that passes through the translucent object, where the detected intensity of the light that passes through the translucent object is relative and indicates one of: the presence of the translucent object based on a lower intensity of the light, or the translucent object is not present based on a higher intensity of the light.

A projection type display apparatus includes: a semiconductor laser element that outputs laser light based on supply of current; a digital mirror device (DMD) that modulates the light output from the semiconductor laser element and emits the modulated light; a projection lens that projects the incident light via the DMD; a drive unit that drives the semiconductor laser element and includes a current detection unit for detecting the current value of the current flowing through the semiconductor laser element; and a controller that, when the current value detected by the current detection unit becomes greater than a first threshold, controls driving of the DMD so that the light output from the DMD will not be incident on the projection lens , and when the current value detected becomes greater than a second threshold greater than the first threshold, causes the drive unit to cut off the supply of current.

A projection system is disclosed including a safety detection system for a protected space, said projection system including a projection light source, a projection imaging system, a projection lens system, a detection source comprising at least of a detection light source and a detection camera comprising at least of a detection sensor, characterized by the fact that the optical axis of the projection source is identical to the optical axis of the detection source and the detection camera at least in the protected space.

An image projection unit includes: a light source unit; a plurality of reflection-type image display elements; a plurality of total reflection prisms configured to guide lights of multiple colors emitted from the light source unit to the reflection-type image display elements and to emit the lights reflected from the reflection-type image display elements; a color synthesis prism configured to receive the lights emitted from the total reflection prisms, synthesize the lights, and emit the synthesized lights; a holding member fixed to the color synthesis prism and holding the reflection-type image display elements; and a base member supporting the color synthesis prism and the plurality of total reflection prisms