An objective optical system for an endoscope consisting of, in order from an object side toward an image side: a front group; and a rear group, wherein: the front group consists of, in order from the object side toward the image side: one negative lens; an optical path deflecting prism; an aperture stop; and one positive lens. The objective optical system for an endoscope satisfies a predetermined conditional expression.

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 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 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 laser processing apparatus includes first and second laser oscillators that emit first and second laser lights (LB1), (LB2) having wavelengths different from each other, an optical fiber that guides first and second laser lights (LB1), (LB2), and laser head (50) configured to condense first and second laser lights (LB1), (LB2), respectively, at predetermined positions of a workpiece. Laser head (50) includes optical path difference generation unit (70) provided inside second housing (51). Optical path difference generation unit (70) is configured to make an optical path length of first laser light (LB1) inside second housing (51) longer than an optical path length of second laser light (LB2).

A plastic light-folding element includes an incident surface, an exit surface, a reflective surface and a reflective optical layer. The incident surface and the exit surface are configured to lead an imaging light enter and exit the plastic light-folding element, respectively. The reflective surface is configured to fold the imaging light. The reflective optical layer is disposed on the reflective surface, and includes an Ag layer, a bottom layer optical film and a top layer optical film. The bottom layer optical film is contacted with the Ag layer, and the bottom layer optical film is closer to the reflective surface than the Ag layer to the reflective surface. A refractive index of the top layer optical film is lower than a refractive index of the bottom layer optical film, and the top layer optical film is not contacted with the Ag layer.

A prism module manufacturing method includes the following steps of: adjusting a first prism and a second prism to have a predetermined temperature difference; using an adhesive layer to be partially connected between the first prism and the second prism so that there is a gap between the first prism and the second prism, wherein the adhesive layer includes a glue material and a plurality of spacers arranged in the glue material. The invention further provides a prism module and a projection device having the prism module. The prism module and the manufacturing method thereof of the invention avoid the interference problem in the prism module so that the image quality and reliability of the projection device can be improved.

A prism module manufacturing method includes the following steps of: adjusting a first prism and a second prism to have a predetermined temperature difference; using an adhesive layer to be partially connected between the first prism and the second prism so that there is a gap between the first prism and the second prism, wherein the adhesive layer includes a glue material and a plurality of spacers arranged in the glue material. The invention further provides a prism module and a projection device having the prism module. The prism module and the manufacturing method thereof of the invention avoid the interference problem in the prism module so that the image quality and reliability of the projection device can be improved.

Examples include a device including a nanovoided polymer element having a first surface and a second surface, a first plurality of electrodes disposed on the first surface, a second plurality of electrodes disposed on the second surface, and a control circuit configured to apply an electrical potential between one or more of the first plurality of electrodes and one or more of the second plurality of electrodes to induce a physical deformation of the nanovoided polymer element.