50results about How to "Shorten the projection distance" patented technology

Both ends of a transparent cover which is formed of a curved member are fitted to a lens guard and a mirror guard, and a free-shaped surface mirror and a free-shaped surface lens are housed in a sealed space defined within a projection type image display device.

A total reflecting prism portion is formed on an image generation source side of a Fresnel lens sheet which constitutes a rear projection type screen. The total reflecting prism portion is formed in an area in which the angle of incidence of a projection image projected from an optical part on the Fresnel lens sheet is at least about 40°. The total reflecting prism portion causes incident light to be outputted as output light at a predetermined output angle by a total reflection phenomenon after a first refraction phenomenon. A refracting prism portion is formed on an image monitoring side of the Fresnel lens sheet. The refracting prism portion is formed in an area opposed to the portion where the total reflecting prism portion is not formed. The refracting prism portion causes incident light to be outputted as output light at a predetermined output angle by a second refraction phenomenon.

A projection optical system satisfies the following conditional equation: 0.01<{(tan θ f1−tan θ f2)−(tan θ n1−tan θ n2)}·(β2/β1)<0.20. If, however, the normal line and longer side directions of a screen surface are z and x directions, respectively, an incident angle component on an xz-plane with respect to the screen surface is an incident angle θ, the larger incident angle θ of a light ray in light rays incident on respective edges of the upper and lower sides of the screen through the center of a stop is θ; f while the smaller incident angle θ of the light ray is θ n; θ f1 and θ f2: the maximum and minimum incident angles θ f at the maximum and minimum projecting magnification absolute values at a focus adjustment time, respectively, θ n1 and θ n2: the maximum and minimum incident angles θ n at the maximum and minimum projecting magnification absolute values at the focus adjustment time, respectively, and β1 and β2: the maximum and minimum incident magnifications at the maximum and minimum projecting magnification values at the focus adjustment time (if the magnification is negative, the magnification value is that at the absolute maximum or minimum time), respectively.

The invention discloses a desktop ultra-short-focus optical module, which belongs to the field of optical systems. The desktop ultra-short-focus optical module is used for imaging a first image projected and displayed by a projector ray machine into an amplified second image, and comprises the projector ray machine, a condensing lens, an aspherical lens, a free curved-surface lens and a free curved-surface reflector which are arranged along an optical path in a tandem manner, wherein the free curved-surface lens is composed of a convex lens and a concavo-vonvex lens. The desktop ultra-short-focus optical module provided by the invention corrects spherical aberration in a collimation and focusing system caused by the condensing lens through the aspherical lens, increases the optical path through the free curved-surface reflector and achieves short-focus projection. Moreover, the desktop ultra-short-focus optical module greatly shortens the projection distance through the ultra-short-focus technology, the projection ratio of the desktop ultra-short-focus optical module ranges from 0.1 to 0.18, and the offset of the first image relative to a main optical axis is greater than 120%.

Images that are bright even on the periphery of a transmissive screen are obtained by reducing reflection loss of the screen when the screen incident angle of the image light entering the upper left and right ends of the screen increases. Incident-side prisms (10), each having at least a plane-of-incidence (c) onto which light comes in, an exit face (d) from which the light that has come in from the plane-of-incidence exits after being refracted, and a refractive face (e) on which the light that has exited from the exit face is refracted and then guided to the image-viewing side of the Fresnel lens sheet (6), are provided in the range where the incident angle of the incoming light becomes equal to or greater than approximately 40 degrees.

The invention relates to the field of a back projection spliced display wall, and discloses an edge-melting seamless-splicing display system. The edge-melting seamless-splicing display system comprises a curtain for projecting an image, at least two projectors which are arranged side by side on the back side of the curtain for projecting the image on the curtain, and a Fresnel lens which is arranged between the projectors and the curtain; the projector image is projected to the curtain through the Fresnel lens; melting overlap is generated on the edge of a picture and the picture of the adjacent projector; the distance between the projectors and the curtain is a formula which is as shown in the specification; and the distance between the Fresnel lens and the curtain is a formula which is as shown in the specification. Edge melting and splicing can be realized by adopting a short-focus lens projector to reduce projection distance and system thickness; and the curtain with relatively small semi-gain visual angle, high gain and high contrast ratio can be selected to expand the selectivity of the curtain, so that the overall display effect of the system can be improved.

A scanning device, a laser projector and an optical device that are capable of accomplishing a wide scanning area in a simple manner include a galvanomirror that is a scanning part scans a laser light in a two-dimensional direction. The laser light from the galvanomirror is incident on a scanning optical system. The scanning optical system includes a first lens group having a positive refracting power and a second lens group having the positive refracting power in this order from the scanning part. The galvanomirror is disposed in the vicinity of a focal position that is located at an incident side of the laser light of the first lens group. The first lens group and second lens group are disposed such that the focal position that is located at an exiting side of the laser light of the first lens group is approximately coincident with the focal position that is located at an incident side of the laser of the second lens group. An absolute value of the value that is calculated by dividing the focal distance of the first lens group by the focal distance of the second lens group is larger than 1.

A projection system comprises the following parts of a telephoto lens capable of independent imaging with a focal length of 70mm to 300mm; a short focus lens capable of independent imaging with a focal length of 3mm to 8mm, wherein the short focus lens is provided with an optical axis with the telephoto lens; and at least one reflective element that changes the direction of the optical axis; thereby, when the telephoto lens forms an image, the short focus lens forms an image to a predetermined position.

The present invention provides a technology that makes it possible to display high-quality images by reducing a reflection loss of the image light entering the upper left and right ends of a transmissive screen. At the image generation source side of the Fresnel lens sheet, a totally reflective prism section (10) is provided that totally reflects incident rays of light and causes the light to exit toward the image-watching side. At the image-watching side of the Fresnel lens sheet (6), a refractive prism section (11) is also provided that refracts the light entering from the totally reflective prism section (10) and causes the light to exit toward the image-watching side. The refractive prism section (11) has a roughed refractive face.

The invention discloses an ultra-short-focus projection optical lens and an ultra-short-focus projection optical system; the ultra-short-focus projection optical lens comprises a shell, a refraction lens group and an aspheric reflector, wherein the refraction lens group and the aspheric reflector are mounted in an inner cavity of the housing and are sequentially and fixedly arranged in a refraction projection direction. An optical axis is correspondingly formed in the shell between the refraction lens group and the aspheric reflector, the refraction lens group sequentially comprises a first spherical lens, a second aspheric lens, a third spherical lens, a fourth spherical lens, a fifth spherical lens, a sixth spherical lens, a diaphragm, a seventh spherical lens, an eighth aspheric lens, aninth spherical lens, a tenth aspheric lens, an eleventh aspheric lens and a twelfth spherical lens from the object side to the image side. According to the technical scheme provided by the invention, at least twelve refraction lenses and one aspheric reflector are arranged, so that the requirements on the projection lens in the aspects of processing and adjustment precision are relatively low.