WO2002033473A1 - Multi-prism image combiner with compensatory film - Google Patents

Abstract

A multi-prism image combiner with compensatory film which can be used in projector, projection TV apparatus and optical sighting device etc., comprising four pieces of right angle prisms of the same material and size. The image combiner as a whole takes a square cross-section, and the adjacent prisms are adhered with each other while the respective ridges of the right dihedral angle of the four prisms are on a common line. Three sides of the image combiner are coated with refractive index compensatory film so that the prisms have the same relative index. Red, green and blue liquid crystal light valves are respectively provided corresponding to each compensatory film. The present image combiner is easy to assemble, convenient to use, and adaptive for circumstance, and enables the combined image to be clear and bright.

Description

 Polygonal prism combiner with compensation film

The present invention relates to an image synthesizing device, and in particular, to a multi-shuttle mirror combiner with a compensation film for spectral synthesis. Background technique

Optical projection devices are widely used in teaching and scientific research. The use of spectral synthesis technology to realize image synthesis and then project a synthesized image not only opens up a new design approach for optical projection technology, it is also the basis for modern projection television equipment, and even high-tech equipment such as sights. The combiner is an important component of the spectral projection imaging device. The basis of combiner imaging is the shuttle mirror combination, which is based on the theory of refracting an infinite beam of light through a prism into an image. Existing shuttle mirror combination technology only makes a parallel beam incident on the plane side of the right dihedral angle of a right-angle prism, and exits from the plane on the other side, as shown in FIG. 1. If a parallel beam is made incident on the oblique plane of the right-angle shuttle lens, as shown in FIG. 2, a half image can be emitted from each of the two right-angle sides of the prism. Based on this principle, prism combination of two infinite systems has been realized. As shown in FIG. 3, it shows a schematic description of the structure and image combining process of a double prism image combiner. This imaging device uses two right-angle prisms a and b to bond the oblique sides together with an adhesive to form a double shuttle mirror combiner having a square cross-section. As shown in the figure, near three of the four sides with four straight dihedral angles, corresponding liquid crystal light valves LCD1, LCD2 and LCD3 are arranged in parallel, which are respectively adapted to open the "gate" by the three primary colors of red, green and blue, so that The transmitted three primary color beams are each imaged at point A of the geometric center of the combiner, and are combined and emitted in the direction of B in the figure. The disadvantage of this double prism combiner is that it is necessary to ensure that each monochrome image is imaged at the center of the entire device. Therefore, in addition to the processing accuracy of the optical devices involved, no less than 0.001 mm is required. At the same time, it is necessary to simultaneously adjust five optical devices including the shuttle mirror and the liquid crystal light valve, which is a very difficult task. The reality is that this adjustment process can take up to 2 hours. Moreover, even with the device so adjusted, The imaging discrimination rate can only reach the standard labels of the 3rd or 4th group (a total of 12 standard labels). In addition, it is suitable for such a double prism combiner, which requires a high incidence angle of the incident light beam. Any slight deviation in the incidence of any single-color light beam will cause the final image to be blurred, and it is difficult to ensure the color reproduction of the image. effect. Therefore, it does not actually have practical significance. (See "Precision Optical Instruments", No. 2, 1998, page 14). Summary of invention

 The object of the present invention is to provide a polygon mirror combiner which is simple to assemble, convenient to use, has strong adaptability to the environment, and has clear imaging. In order to achieve the above g, the present invention provides a multi-shuttle mirror combiner, which is composed of four right-angle prisms of the same material and size. The entire combiner has a square cross-section, and the right dihedral sides of adjacent right-angle prisms. Adhesive to each other, and the edges of the straight dihedral corners of the four prisms are collinear; three sides of the combiner are plated with a refractive index compensation film, and the relative refractive indices of the shuttle lenses are equal; they are arranged corresponding to each compensation film Red scar, green scar and blue scar LCD light valve. By adopting the polygon prism combiner of the present invention, since the geometric center of the entire combiner naturally forms the collinear line of the right dihedral angle of each prism, it does not need to perform the complicated "centering" work like the double prism combiner. Moreover, when the combiner of the present invention is used, since the light beam is incident from the oblique side of each combining prism, and because of the geometric symmetry of each combining prism, the combining image is on the intersecting side of the adjacent shuttle lens, so it is no longer Limiting the incident direction of the light beam can greatly facilitate the use. In particular, since the relative refractive indices of the combining shuttle lenses of the combiner of the present invention are equalized, the phases of the image components in the frequency bands participating in the combination are always ensured to ensure that the final composite image is clear, lifelike, and free of aberrations. No distortion. Compared with the prior art, the composite image is also detected using the No. 5 discrimination rate plate, which can reach the standard group 10 standard bar. Brief description of the drawings

 FIG. 1 is a schematic diagram illustrating ordinary shuttle lens imaging;

 FIG. 2 is a schematic diagram illustrating imaging of the combiner of the present invention using a shuttle lens;

 Figure 3 shows the structure and imaging principle of a dual shuttle lens combiner;

1 FIG. 4 is a schematic structural diagram of a polygon mirror combiner with compensation according to an embodiment of the present invention. Detailed description of the invention

The structure and operation of the damping polygon mirror combiner of the present invention will be further described in detail through specific embodiments with reference to the accompanying drawings. Referring to FIG. 4, the combiner of the present invention includes four right-angle prisms of the same geometric size, which are bonded to each other with ultraviolet light-sensitive adhesive on the sides constituting a right dihedral angle, and inclined at an angle opposite to the right The plane is a light incident surface or an outgoing surface; the cross section of the combiner is square, and the collinear line of the straight dihedral angle of the cross section of each shuttle mirror becomes the center line of the cross section. Each prism used in this embodiment is made of K9 crown glass, and its cross section is an isosceles right-angled triangle. The length of the hypotenuse of the triangle is 34mm, and the height of the hypotenuse is 17mm. The length of the assembled transverse device is also 34mm, that is, the overall shape is cubic. As we all know, the basis of spectral synthesis imaging is to divide the incident image into three primary color images. Then the subsequent combiner must use the same absorption characteristics and optical path length to accurately make the three at the imaging point in the same phase. Compound to restore the original color and intensity of the incident image. This is the basic guarantee for the quality of the final composition. The refractive index of any "bare" shuttle lens will not be the same, which directly affects the clarity of the composite image. In this embodiment, a refractive index compensation film (or a damping film) is plated on the incident side of the light beam of the combining prism, and the thickness of the film is appropriately set and controlled, so that the refractive indexes of the four prisms can be adjusted to equal refractive indexes. The third digit after the decimal point remains the same. Provides guarantee conditions for improving the quality of image synthesis of the combiner. Can increase the height and sharpness of the composite image at the same time. The refractive index compensation film of this embodiment is made of a magnesium fluoride material. Known liquid crystal light valves for combiners are generally available in three sizes, 33mm, 23mm, and 18mm.釆 The multi-shuttle mirror combiner with a retaining film of this embodiment can be used for well-known and commonly used specifications. LCD light valve. Moreover, the combiner adopting this embodiment does not need to be like an ordinary double prism combiner.

Claims

1. A kind of polygon mirror combiner with a holder, consisting of four right-angle shuttle lenses of the same material and size. The entire image-forming device has a square cross-section. It is characterized in that the sides of the right dihedral corners of adjacent right-angle shuttle lenses are mutually Bonded, and the collinear edges of the four dihedral corners of the four shuttle lenses are collinear; the three sides of the combiner are plated with a refractive index compensation film, and the relative refractive indices of the prisms are equal; and they are arranged corresponding to each compensation film Red scar, green scar and blue LCD light valve. 2. The polygon mirror combiner according to claim 1, wherein the refractive index compensation film is made of a magnesium fluoride material. 3. The polygonal prism combiner according to claim 1, wherein the cross-section of the right-angle prism is an isosceles right-angled triangle with a hypotenuse 34 mm in length and a height of 17 mm on the hypotenuse.  4. The multiple shuttle lens combiner according to any one of claims 1 to 3, wherein the right-angle prism is made of K9 crown glass. 5. The polygon mirror combiner according to claim 3, wherein a height of the combiner is 34 mm.