TW567341B - Optic system for projecting display - Google Patents

Abstract

The present invention provides an optic system for projecting display, which includes a light source for providing light; an illuminating module for receiving the light from the light source and outputting the linearly polarized white light; a color selecting component for receiving the linearly polarized white light, and outputting a first color light with the second polarization, a second color light with the first polarization, and a third color light with the second polarization; a prism assembly; a projection lens; and, the first to third reflective light valves, which can change the polarization of the first to third color lights from the prism assembly, and reflect them to the prism assembly for being irradiated into the projection lens through the prism assembly.

Description

567341 _Case No. 91102859_year month_i ± i ^ _ V. Description of the Invention (1) Field of the Invention The present invention relates to a projection display, and particularly to an optical system with a reflective light valve in the projection display. Explanation of Related Techniques In recent years, the importance of information visualization has been widely recognized, so the demand for projection displays has also increased rapidly. High display quality, low production cost, and lightness of products are the main goals of the industry research and development. U.S. Patent No. 5,7 7 7, 7 8 9 issued to Chiu et al. Discloses an optical system including a plurality of reflective light valves, a polarizing beam splitter, a plurality of color image combinations, and an illumination System, and a screen. The main disadvantage of this prior art optical system is that due to the angular dependence of the traditional polarizing beam splitter, that is, the traditional polarizing beam splitter generates polarized aurora in different directions for light incident on it at different angles. , Resulting in a serious problem of uneven contrast and low contrast; the back focal length of the optical system is quite long, resulting in a problem that the projection image it can provide is low in brightness or requires a larger projection lens size; and The optical system involves serious birefringence problems, which seriously affects its projection quality. U.S. Patent No. 5, 8 2 6, 9 5 9 issued to At such i, discloses a projection display device including a three-piece / dual-color mirror, three polarizing beam splitters, a plurality of reflective light valves, one Fork-type two-color chirp device, a lighting system, and a screen. The main disadvantages of this prior art projection display device are: the large number of components leads to complicated structure, high cost, and large size; the back focal length of the projection display device is quite long, which leads to its

567341 _Case No. 91102859_ 年月 日 __ V. Description of the invention (2) The problem that the provided projected image has a low brightness or requires a larger projection lens size. SUMMARY OF THE INVENTION An object of the present invention is to provide an optical system for a projection display, in which a polarized beam splitter having no angular dependence is used in a grate assembly, such as a wire grid polarized beam splitter (wire gr idp01 ar i zer), instead of using a traditional polarizing beam splitter with angular dependence, it can avoid or slow down the aforementioned problems of uneven contrast and low contrast. Another object of the present invention is to provide an optical system for a projection display, in which the back focal length is relatively short, so that the aforementioned problems of low brightness of the projected image or a larger projection lens size can be avoided or mitigated. Yet another object of the present invention is to provide an optical system of a projection display, which has a unique geometric structure that enables it to avoid or slow down the aforementioned birefringence (b i r e f r i ng e n c e) problem, and thus can improve projection quality. Yet another object of the present invention is to provide an optical system for a projection display, which has a simple structure and can avoid the aforementioned problems of high cost and large size. In order to achieve the above objects, an optical system of a projection display according to a preferred embodiment of the present invention includes a light source for providing light; an illumination module that receives light from the light source and outputs linear polarization A white color selection component that receives the linearly polarized white light and outputs a 'first color light having a second polarization, a second color light having a first polarization, and a third color light having a second polarization; A first assembly including a first pair of groups consisting of a first pair and a second pair, and a second pair of groups consisting of a third pair and a fourth pair, the first pair and The second edge

567341 _Case No. 911Q2859_ Year and Month _ί ±± _ V. Description of the invention (3) A first two-color mirror is formed between the mirrors, and a second two-color is formed between the third and fourth * Mirror, a polarizing beam splitter is formed between the first pair of chirps and the second pair of chirps, and both the first and second dichroic mirrors can penetrate the third color light and make the first color The light and the second color light are reflected, and the chirp assembly receives the first color light having the second polarization, the second color light having the first polarization, and the third color light having the second polarization from the color selection component; A projection lens; and first to third reflective light valves, which can be used to change the polarities of the first to third colored lights from the cymbal assembly and reflect them to the cymbal assembly, and then pass through the cymbal assembly The assembly shoots into the projection lens. Description of the drawings: Fig. 1 is a schematic diagram showing an optical system of a projection display according to a preferred embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an imaging system in the optical system. Detailed description Please refer to FIGS. 1 and 2. An optical system of a projection display according to a preferred embodiment of the present invention includes an illumination system 1 and an imaging system 2. The lighting system 1 includes a light source 12 for providing light; and a lighting module 14 for receiving light from the light source 12 and outputting linearly polarized white light 10. The imaging system 2 includes a color separation assembly 20 and a projection lens 30. Color separation assembly 20 includes a stack of assemblies 2 2, a color selection assembly 2 4, and three reflections

567341 _Case No. 91102859_ Che Yueyue Amendment --- V. Description of the Invention (4) Type light valves 25R, 25G, 25B, and reflection type light valves 25R, 25G, 25B can reflect red, green, and blue light, respectively. And make these color lights change the polarity, that is, from P polarity to S polarity, or from S polarity to P polarity. In this case, referring to Fig. 2, light of P polarity means that the direction of the electric field vector of the electromagnetic wave is parallel to the paper surface of Fig. 2; light of S polarity means that the direction of the electric field vector of the electromagnetic wave is perpendicular to the paper surface of Fig. 2. The prism assembly 22 includes, for example, four columnar prisms 22, 222, 223, and 224 made of glass, of which the sizes and shapes of the two prisms 221 and 223 are equal, and their cross sections are isosceles triangles, and The bottom angles are all 30 °. The cross section of 剖面 2 2 2 is a right-angled trapezoid, and the length of the bottom side is equal to the waist length. The length of the right-angled side of the right-angled trapezoid is half of the length of the base of the isosceles triangle. The length of the side is equal to the length of the waist. A two-color mirror 27 is formed between the bottom edge of the right-angled trapezoid and one waist of the cross-section isosceles triangle of 稜鏡 2 2 1. The upper side is positioned on a straight line, that is, one of the sides 2 2 1 a of 稜鏡 2 2 1 and one of the sides 2 2 2 a of 稜鏡 2 2 2 are in a common plane.稜鏡 22 4 is an equilateral triangle whose side length is equal to the waist length of the isosceles triangle. A bicolor mirror 28 is formed between one side of the equilateral triangle and one waist of the isosceles triangle of the section 稜鏡 22 3; the other side of the equilateral triangle and the isosceles of the section of 稜鏡 2 2 3; the other waist of the triangle Substantially positioned on a straight line, that is, 稜鏡 2 2 3 has a side 2 2 3 a and 稜鏡 2 2 4 has a side 224 a in a common plane. On this common plane, a layer of wire grid polarizing beam splitter 29 is also applied on the side surfaces 2 2 3 a and 2 2 4 a. As shown in FIG. 2 ’, the line tree polarizing beam splitter 2 9 has a very small air gap 2 2 0 and a rib.

Page 7 567341 _Case No. 91102859_ Year Month Date 佟; ^ V. Description of the invention (5) The side 2 2 1 a of the mirror 2 2 1 and the side 2 2 2 a of the 2 2 2 are opened. The dichroic mirror 27 and the dichroic mirror 28 both penetrate the incident blue light and reflect the red light and the green light. The wire grid polarizing beam splitter 29 penetrates p-polarized light incident and reflects S-polarized light. The color selection module 24 and the three reflection-type light valves 25R, 25G, and 25B are positioned on the periphery of the prism assembly 22, as shown in Fig. 2, at appropriate positions. As understood by those of ordinary skill in the art, the corresponding colored light reflected from each of the reflective light valves 25R, 25G, and 25B is transmitted through the cymbal assembly 22 to a length. Part 2 4 sieve Polarity 2 7 Mirror 2 7 Anti-air gap Its reflection can be in the grid. Each light path to the projection lens 30 should preferably have the same light path and linearly polarized white light 10 to enter the color selection module 24. The color selection group selects red light R with S polarity and green light with p polarity. gp and f Bs. These polarized three primary colors of light hit the dichroic mirror, blue light B s penetrates the dichroic mirror 27, red light R s and green light G p are shot in two colors, and blue light Bs then hits the surface 222a of 稜鏡 2 2 2 Through the space 2 2 0 to the grid-type polarizing beam splitter 29 with no angular dependence, it is reflected by the reflective light valve 25B and the reflective light valve 25B to reflect the blue light Bs. p-polar blue light, and the penetrating polarizing beam splitter 29 and the dichroic mirror 28 enter the projection lens 30 and the red p, which is reflected by the dichroic mirror 27. ^ At total reflection, and then wire grid type; = the two external interfaces change their polarities to make it, and can simultaneously wire grid polarized beam splitter 29, after 稜鏡 22 =, Rp, red light Rp penetrated by The dichroic mirror 28 is reflected into the projection lens 30. " Total reflection on the surface, most

567341 Case No. 911 (Amended in December 12859) 5. Description of the invention (6) --- The green light gp reflected by the dichroic mirror 27 is totally reflected at the interface outside 稜鏡 221 and then penetrates the wire grid polarized beam splitting器 29 ， Reflected to the reflective light valve 2 5 G, the reflective light valve 2 5 G reflects the green light gp, and can change its polarization H at the same time to produce green light G s, and the green light gs is polarized by the wire grid The beam splitter 2 9 reflects, and totally reflects outside the interface 稜鏡 22 3, and finally is reflected by the dichroic mirror 28 into the projection lens 30. Since the wire grid polarizing beam splitter 2 9 has no angular dependence, All applied polarized polar lights (perpendicular to the paper surface of Fig. 2) incident on the wire grid polarized beam splitter 29 at various angles are reflected & without changing their polarity ', that is, the direction of the electric field vector of the electromagnetic wave is still It is completely perpendicular to FIG. 2, and the surface is the same. All the polarizing lines of the penetrating-line peach-type polarizing beam splitter 29 also have the same polarity, that is, its electrical correction. The direction inside is still completely parallel to the paper surface in Figure 2, so it can avoid or slow down the contrast unevenness and contrast in the prior art. The low side of the issue. The above are merely used to facilitate the description of the preferred embodiments of the present invention, but not to limit the scope of the present invention. Any changes made according to the content of the present invention without departing from the spirit of the present invention are Belongs to 3 out of 5 of this hair. For example, instead of using a traditional polarized beam splitter to replace a wire-grid polarized beam splitter, the number of reflection beam valves 2 5 R, 2 5 G, 2 5 B, and cymbal assembly 2 2 is added. And color filter (c ο 1 〇rfi 11 er), phase retardation film (retardation film), color selection module, or color polarizer (color polarizer), to help purify color or polarized light, in each two-color An additional layer of retardation film, color selection module, or color polarizer is applied to the surfaces of the mirrors 27 and 28.

Page 9 567341 ___ Case No. 91102859_Year Month Date__ V. Description of the invention (7) (c ο 1 〇r ρ ο 1 arizer), which helps to purify polarized aurora, A retardation film, color selection module, color polarizer or neutral polarizer is added between the mirror assembly 2 and 2 to help purify the color or polarized light or Replacing the wire grid polarized beam splitter 29 with VikuitiTM dual brightness enhancement film (DBEF) produced by American 3M Company does not depart from the scope of the present invention.

Page 10 567341 _Case No. 911Q2859_ Year Month Revision _ Brief Description of the Drawings Figure Description: * Figure 1 is a schematic diagram showing an optical system of a projection display according to a preferred embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing the imaging system in the optical system. 0 Number description: 1 Illumination system 10. Linearly polarized white light 12 Light source 14 Lighting module 2 Imaging system 20 Separation assembly 22 稜鏡 Total Into 24 color selection components 2 5 R reflective light valve 2 5 G reflective light valve 2 5 B reflective light valve 27 dual color mirror 28 dual color mirror £ 29 polarizing beam splitter '30 projection lens 221 cylindrical prism 221a side

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Claims (1)

567341 _Case No. 911Q2859_Year Month Date__ VI. Patent Application Scope 1. An optical system for a projection display, comprising: a light source 'to provide light; a lighting module to receive light from the light source, and Output linearly polarized white light; a color selection component that accepts the linearly polarized white light and outputs a first color light having a second polarization, a second color light having the first polarization, and a second color polarization The third color light; the first assembly, including a first pair of groups consisting of the first pair and the second pair and a second pair of groups consisting of the third pair and the fourth pair, the first A first dichroic mirror is formed between a toe and the second ridge, a second dichroic mirror is formed between the third toe and the fourth ridge, the first pair of cymbals and the second pair A polarizing beam splitter is formed between the cymbals. The first dichroic mirror and the second dichroic mirror can both penetrate the third color light and reflect the first color light and the second color light. The first color light having the second polarization in the color selection component, A second color light, and a third color light of a second polarity; a projection lens; and first to third reflective light valves, which can be used to change the polarity of the first to third color lights from the puppet assembly, respectively It is reflected to the cymbal assembly, and then enters the projection lens through the cymbal assembly. 2. An optical system of a projection display according to item 1 of the scope of the patent application, wherein the polarizing beam splitter is a polarizing beam splitter with no angular dependence Page 13 567341 _Case No. 91102859_Year Month and Date_ί ±± _ Six, the scope of patent application. 3. An optical system for a projection display according to item 1 of the scope of the patent application, wherein the polarizing beam splitter is a polarizing beam splitter having no angular dependence. 4. An optical system of a projection display, comprising: a light source for providing light; a color selection component that receives light from the light source and outputs a first color light having a second polarity and a first polarity light The second color light, and the third color light of the second polarized polarity; a stack of assemblies including the first to fourth columnar stacks, wherein the first columnar stack forms a layer of polarized poles without angle dependence on one side. Beamsplitter, this polarizing beamsplitter is adjacent to one side of the second columnar ridge, this ridge assembly accepts the first color light with the second polarization and the first polarization Two-color light, and a third color light of a second polarity; a projection lens; and first to third reflective light valves, which can be used to change the polarity of the first to third color lights from the cymbal assembly and Reflected to the cymbal assembly, and then shot into the projection lens via the cymbal assembly. r 5. The optical system of a projection display according to item 4 of the scope of the patent application, wherein the polarizing beam splitter without angular dependence of the layer is a wire grid Page 14 567341 _Case No. 91102859 _Hi_ VI. Patent application scope Polarizing beam splitter. 6. An optical system of a projection display, comprising: a light source to provide light; a color selection component that receives light from the light source and outputs a first color light having a second polarization and a first polarization A second color light of a polar polarity and a third color light of a second polarity polarity; a ballast assembly including first to fourth columnar ballasts, wherein two adjacent first side surfaces of the first columnar ballast and the first An acute plane angle is formed between the two sides, and a polarizing beam splitter is formed on the second side. The chirp assembly receives the first color light having the second polarization and the first polarization from the color selection component. Two-color light, and a third color light of a second polarity; a projection lens; and first to third reflective light valves, which can be used to change the polarity of the first to third color lights from the cymbal assembly and Reflected to the cymbal assembly, and then incident into the projection lens via the cymbal assembly, the first reflective light valve is adjacent to the first side. 7. The optical system of a projection display according to item 6 of the scope of patent application, wherein the acute angle of the plane is greater than or equal to 15 degrees and less than or equal to 35 degrees. 8. An optical system of a projection display, comprising: a light source for providing light; Page 15 567341 Case No. 91102859 _a Amendment VI. Patent application scope: a color selection module that accepts light from the light source and outputs a first color light with a second polarity and a second color light with a first polarity And third polarized light of a second polarity; a stack of assemblies including first to fourth columnar stacks, wherein each columnar stack has three or more sides; the first to fourth All sides of the columnar maggot are respectively parallel to the extending direction of the columnar maggot body, and a first space is formed between the first side of the first columnar maggot and the second side of the second columnar maggot. Area, a second space is formed between the first side of the second columnar puppet and the second side of the third columnar puppet, and the first side of the third columnar puppet and the fourth columnar A third spacer is formed between the second side of the cymbal, and a fourth spacer is formed between the first side of the fourth columnar cymbal and the second side of the first columnar cymbal, the first spacer Forming a dichroic mirror with each of the third interval, the second interval and the fourth interval A polarizing beam splitter is formed in each of the zones, and the unitary assembly receives the first color light having the second polarization, the second color light having the first polarization, and the second light having the second polarization from the color selection component. Three-color light; a projection lens; and first and third reflective light valves, which can be respectively used to change the polarity of the first to second color light from the concrete assembly and reflect to the concrete assembly, and then pass through The puppet assembly shoots into the projection lens. 9 · According to the application, the scope of the project is an optical system of a projection display described by 8 households, in which the polarizing beam splitter is a layer of polarizing beam splitter without angle dependence. 0 Page 16 567341 Page 17