An illumination system and a projection apparatus are provided. The illumination system includes a coherent light source, an optical module, and a first light-diffusing device. The coherent light source emits a coherent light beam. The optical module and the first light-diffusing device are located on a transmission path of the coherent light beam. The optical module has an optical surface and a light-diffusing surface, and the coherent light beam focuses on a first position through the optical surface of the optical module. The first light-diffusing device is located at the first position or in vicinity of the first position. The coherent light beam passes through the first light-diffusing device so that a diffusion angle of the coherent light beam is sequentially changed. A display frame exhibiting a uniform luminance is thereby provided by the illumination system and the projection apparatus of the invention.

An illumination optical system for endoscope includes a rod lens as an optical element. The optical element includes a proximal end surface through which light enters and a distal end surface configured to emit the light. The distal end surface includes a diffusion region configured to diffuse emitted light. The diffusion region includes a plurality of concave portions and a plurality of peripheral regions surrounding the concave portions. Each concave portion includes a plurality of inclined surfaces as total reflection surfaces that are inclined with respect to the distal end surface. Each peripheral region includes a transmission surface configured to emit light totally reflected by the total reflection surfaces after passing through the proximal end surface and light not totally reflected by the total reflection surfaces.

An optical body including: a first optical layer which has a surface having a convex profile in which a plurality of one-directionally extending elongated convex portions are one-dimensionally aligned in one direction; an inorganic layer disposed on the surface of the first optical layer on a side having the convex profile and a second optical layer disposed on a side of the inorganic layer so that the convex profile is embedded; wherein the convex profile meets at least one of the following (1) to (4): (1) a height varies in an extending direction in each of the elongated convex portions, (2) a ridge portion meanders in a direction perpendicular to both the extending direction and a height direction of the convex portion in each of the elongated convex portions, (3) heights of the elongated convex portions adjacent to each other are different from each other, and (4) a triangular prism-shaped convex portion and an elongated convex portion having a curved surface are adjacent to each other.

Provided is an anti-glare film that can suppress reflection and impart a sense of luxury by suppressing surface graininess. The anti-glare film includes a first main surface and a second main surface opposite to the first main surface, in which when the average inclination angle with a cut-off value of 0.8 mm of the first main surface is defined as θa.sub.0.8 and the average inclination angle with a cut-off value of 2.5 mm of the first main surface is defined as θa.sub.2.5, the anti-glare film satisfies the following Equations (1) and (2).

0.20 degrees≤θa.sub.0.8≤0.70 degrees   (1)

|θa.sub.2.5−θa.sub.0.8|≤0.10 degrees   (2)

A directional backlit type display device comprises a backlight provided with a light source module, a reflective narrow-angle diffuser provided with an array of a plurality of micro-curved mirrors reflecting the light and uniformly diffusing the light with a narrow diffusion angle, the backlit type display panel being configured on a projecting path where the reflective narrow-angle diffuser reflecting the light to an observer, the backlit type display panel displaying an image projected to an eye box of the observer by the reflected light, at least one of the micro-curved mirrors of the reflective narrow-angle diffuser corresponding to each pixel of the image, uniformly diffusing the light of each pixel to the eye box of the observer, the diffusion areas of all pixels on the backlit type display panel superimpose on the eye box of the observer.

The present disclosure provides a sub-wavelength structural material having compatibility of low detectability for infrared, laser, and microwave, which includes, from top to bottom, a metal type frequency selective surface layer I, a dielectric layer I, a metal type frequency selective surface layer II, a dielectric layer II, a resistive film, a dielectric layer III. Each of the metal type frequency selective surface layers is a sub-wavelength patch type array, and metal used by the metal type frequency selective surface layers has a characteristic of low infrared emissivity. The present disclosure modulates a phase by using a phase difference generated by patches with different sizes on the metal type frequency selective surface layer I, so as to control backscattering of incident electromagnetic waves to achieve compatibility of low detectability for laser and infrared, while the bottom three layers achieve absorption of microwave.

The invention relates to an optical imaging system (100) and a device for floating display, and a surround-view display device (2000). The optical imaging system (100) sequentially defines, along the optical axis thereof, an object plane (10), a first image plane (101) and a second image plane (102), and the optical imaging system (100) comprises at least one imaging unit (110) arranged between the object plane (10) and the first image plane (101) on the optical axis, with the at least one imaging unit (110) having different light converging capabilities in a first direction and in a second direction, and the first direction and the second direction being orthogonal to the optical axis, respectively; and a main diffusion screen (120) diverging light in the second direction, the optical imaging system (100) being configured such that a light beam from a point on the object plane (10) forms a line image in the first direction on the first image plane (101), and the light beam from a point on the object plane (10) forms a line image in the second direction on the second image plane (102), with the second image plane (102) being a floating image plane.

A semiconductor device package includes a light-emitting device, a diffuser structure, a first optical sensor, and a second optical sensor. The light-emitting device has a light-emitting surface. The diffuser structure is above the light-emitting surface of the light-emitting device. The first optical sensor is disposed below the diffuser structure, and the first optical sensor is configured to detect a first reflected light reflected by the diffuser structure. The second optical sensor is disposed below the diffuser structure, and the second optical sensor is configured to detect a second reflected light reflected by the diffuser structure.

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.

The present invention provides a viewing angle diffuser film and a display panel, including a base substrate and refractive protrusions. By setting space ratios of adjacent refractive protrusions in a first direction and a second direction, refraction directions of the viewing angle diffuser film can be controlled, and therefore light diffusion effects can be controlled. In the display panel of the present invention, the space ratios of the refractive protrusions in different directions are adjusted according to different usage scenarios to improve display brightness and reduce color shifts.