CN101206391A - Color Separation and Combiner for Ultra High Brightness Digital Cinema Projector - Google Patents

Abstract

The invention discloses a color separation and combiner of an ultra-high-brightness digital movie projector. White light is totally reflected by the first total internal reflection prism and then passes through the second total internal reflection prism, the Phillips compensation prism, the first air gap of the Philips prism, and the Philips anti-red prism. The color-synthesizing film divides the white light into two beams of red and blue-green light. One of the reflected red lights is totally reflected by the first air gap of the Philips prism and reaches the image chip of the red light path. The other transmitted blue-green light passes through the After passing through the Philips anti-blue prism, it is divided into two beams of blue and green light by the anti-blue-transparent-green color separation film. One of the reflected blue lights is totally reflected by the second air gap of the Philips prism and reaches the image chip of the blue light path. A beam of transmitted green light passes through the Philips green prism and reaches the image chip of the green light path. The invention can be used in movie projectors, the brightness of which is as high as 8000-25000 lumens. The invention can avoid the deterioration of the image quality of the device caused by high heat, and even cause the risk of device rupture.

Description

Color Separation and Combiner for Ultra High Brightness Digital Cinema Projector

technical field

The invention relates to a color separation and combination device, in particular to a color separation and combination device for an ultra-high-brightness digital movie projector.

Background technique

The ultra-large screen and ultra-high brightness digital cinema projector has the following important features: First, because the brightness is as high as 8000-25000 lumens (7kW, 25000 lumens; 3kW, 15000 lumens; 1.25kW, 8000 lumens), the screen width can be realized 5-25 meters super large screen projection. Secondly, it can process and convert various digital signals and analog signals, conveniently connect computers, DVD and other audio-visual equipment and various programs played by TV stations, and you can find the required programs on the Internet instantly. Finally, 3D or stereoscopic image projections are easily achieved using digital compositing techniques. Because these features greatly overcome the various shackles of film production and application, it is favored in cinemas first, and shows great application prospects in large terminal display systems, intelligent command systems, military, education, business and other fields.

Due to the ultra-high brightness, the color separation and combiner is seriously heated. It is extremely difficult to control the working temperature of the color separation and combiner below 70°C, and heat dissipation has become the first problem. Due to heat problems, current projectors use DMD image sources based on MEMS instead of LCD panels. The color separation and combiner in the optical machine must also withstand high energy and high heat, so the present invention uses a total internal reflection prism system plus a Philips prism system, as shown in Figure 1.

In order to improve the thermal characteristics of the color separation and combiner, the present invention has the following characteristics: all prisms use K9 or Schott BK7 glass with excellent thermal performance and stable chemical properties. The anti-red transparent blue-green and anti-blue transparent green color separation films on the prism use Ta2O5, Nb2O5 or TiO2 as the high refractive index film, and Al2O3 as the low refractive index film. Since the thermal conductivity of Al2O3 is more than 10 times higher than that of SiO2 , thus improving the thermal conductivity of the color separation film, not only reducing the image quality deterioration caused by high heat caused by optical surface deformation, and even causing the prism to break, but also reducing the angle effect and polarization effect. All prism interfaces are set as air gaps without any glued surfaces to prevent glueline failure at high temperatures. Moreover, a heat sink is installed in the non-light-transmitting part where the temperature of the prism is higher. When the temperature of all color-separation and color-combining films changes from room temperature to 80°C, the shift of the wavelength corresponding to the transmittance of 50% is less than 1nm, which ensures that the color of the image is stable when the temperature rises. The air gaps at the interface of all prisms are 20 microns to 40 microns to prevent the internal reflection from being too small due to the expansion of the glass at high temperature.

Contents of the invention

The object of the present invention is to provide a color separation and combiner for an ultra-high-brightness digital cinema projector to solve the above problems.

In the color separation and color combiner used in ultra-high-brightness digital cinema projectors, white light is totally reflected by the first total internal reflection prism and then passes through the second total internal reflection prism, the Philips compensation prism, and the first air gap of the Philips prism After the Philips anti-red prism, the anti-red transparent blue-green color separation film divides the white light into two beams of red and blue-green light, and one of the reflected red lights is totally reflected by the first air gap of the Philips prism and reaches the red light. The optical path image chip, another beam of transmitted blue-green light passes through the Philips anti-blue prism and is divided into two beams of blue and green light by the anti-blue-transparent-green color separation film, and one of the reflected blue lights passes through the Philips The second air gap of the prism is totally reflected and reaches the image chip of the blue light path, and the other transmitted green light passes through the Philips green prism and reaches the image chip of the green light path.

The material of the prism is K9 or Schott BK7 glass. The anti-red transparent blue-green color separation film and the anti-blue transparent green color separation film use Ta2O5, Nb2O5 or TiO2 as the high refractive index film, and Al2O3 as the low refractive index film. The non-light-transmitting part of the prism is provided with a heat sink. The air gap interval at the prism interface is 20 microns to 40 microns.

The color separation and combiner provided by the invention includes a total internal reflection prism system and a Phillips prism system. All prisms use K9 or Schott BK7 glass with excellent thermal properties and stable chemical properties, while conventional prisms can choose different glasses according to application requirements. The anti-red and blue-green and anti-blue and green color-separation films on the prism use Ta2O5, Nb2O5 or TiO2 as the high-refractive index film, Al2O3 as the low-refractive-index film, and the conventional color-separation film uses SiO2 as the low-refractive-index film. Because the thermal conductivity of Al2O3 is more than 10 times higher than that of SiO2, the thermal conductivity of the color separation film is improved, and the temperature difference of the entire film layer is reduced, which not only reduces the optical surface deformation caused by high heat Image quality deteriorates, even prisms break, and angle effects and polarization effects are reduced. All prism interfaces are air gaps without any glued surface to prevent the glue layer from failing at high temperatures, while conventional Phillips prisms have both air gaps and glued surfaces. The prism of the present invention is equipped with a heat sink at the non-light-passing part with a higher temperature, while the conventional Phillips prism does not need a heat sink. When the temperature of all color-separation and color-combining films changes from room temperature to 80°C, the drift of the wavelength corresponding to the transmittance of 50% is less than 1nm, which ensures that the color of the image is stable when the temperature rises, while the drift of conventional color-separation and color-combining films can be reduced. Up to about 20nm. Finally, the air gap intervals of all interfaces of the Phillips prism of the present invention are 20 microns to 40 microns, so as to prevent the air gaps from being too small due to glass expansion at high temperatures and internal reflection failure, while the conventional air gap thickness is about 10 microns .

The color separation and combiner of the invention can be used in digital movie projectors with a brightness as high as 25,000 lumens, and can still maintain excellent image quality during operation.

Description of drawings

Figure 1 is a schematic structural diagram of a color separation and combiner used in an ultra-high-brightness digital cinema projector; in the figure: total internal reflection first prism 1, total internal reflection second prism 2, Philips compensation prism 3, Philips anti-red Prism 4, Philips anti-blue prism 5, Philips green prism 6, total internal reflection air gap 7, Philips prism first air gap 8, Philips prism second air gap 9, Philips prism The third air gap 10, the anti-red and blue-green color separation film 11, the anti-blue and green color separation film 12, the red light path image chip 13, the blue light path image chip

14. Green light path image chip 15;

Fig. 2 is a structural schematic diagram of a radiator of the present invention; among the figures: a first radiator 16, a second radiator 17, a third radiator 18;

Fig. 3 (a) is the structural representation of total internal reflection+Philip system color separation and color combiner of the present invention;

Fig. 3 (b) is the structural schematic diagram of conventional Philips system color separation and color combination prism;

Fig. 4 is a graph comparing the spectral characteristics of the color-separation and color-combining film of the present invention at a temperature of 80°C with room temperature.

Detailed ways

As shown in Figure 1, the color separation and color combiner for ultra-high-brightness digital cinema projectors is characterized in that the white light is completely reflected by the first total internal reflection prism 1 and then passes through the total internal reflection second prism 2, Phillips compensation Prism 3, Philips prism first air gap 8, after Philips anti-red prism 4, anti-red transparent blue-green color separation film 11 divides white light into two beams of light, red and blue-green, and one of them reflects red light Through the total reflection of the first air gap 8 of the Philips prism, it reaches the image chip 13 of the red light path, and the blue-green light transmitted by another beam passes through the Philips anti-blue prism 5 and is reflected by the blue-transparent-green color separation film 12 and then Divided into two beams of blue and green light, wherein one beam of reflected blue light is totally reflected by the second air gap 9 of the Philips prism, and reaches the image chip 14 of the blue light path, and the other beam of transmitted green light passes through the Philips green prism 6 , reaching the green light path image chip 15. After being modulated by the red light path image chip 13, the blue light path image chip 14, and the green light path image chip 15, the red, blue, and green primary color lights return to the original path to synthesize a color image, and pass through the first total internal reflection prism 1 , The total internal reflection second prism 2 is projected onto the screen.

The material of the prism is K9 or Schott BK7 glass. The anti-red and blue-green color separation film 11 and the anti-blue and green color separation film 12 use Ta2O5, Nb2O5 or TiO2 as the high refractive index film, and Al2O3 as the low refractive index film. The non-light-transmitting part of the prism is provided with a heat sink. The air gap interval at the prism interface is 20 microns to 40 microns.

As shown in FIG. 2 , the Phillips prism of the present invention is provided with a first heat sink 16 , a second heat sink 17 and a third heat sink 18 at a non-light-transmitting position with a higher temperature. The position with the highest temperature of the color-separation and color-combining film is the light-passing position, but the light-passing position cannot be installed with a radiator because the radiator blocks light, so the radiator can only be placed on the sub-hot part. So how to reduce the temperature of the highest temperature part? The invention adopts the Al2O3 film with very high thermal conductivity, so that the heat at the highest temperature part can be rapidly diffused to the entire film surface, and then rapidly diffused into the air through three radiators.

Figure 3 is a comparison of total internal reflection and Phillips dichroic prisms of the present invention with conventional Philips dichroic prisms. Because the temperature on the prisms 1-6 is not only high, but also the temperature distribution is uneven, if the thermal performance of the glass is poor, even if the above-mentioned Al2O3 film with high thermal conductivity is used as the low refractive index material of the color separation and color combination film system, the glass may still break. , must choose K9 or BK7 for this reason. All prism interfaces of the present invention are air gaps, including total internal reflection prism air gap 7 and Phillips prism air gap 8, 9, 10. This system cannot have any glued surface to prevent the glue layer from failing at high temperatures. However, the conventional Philips prism has both an air gap and a glued surface, especially the air gap 10 is glued. To the total internal reflection prism air gap 7 of the present invention and the air gap 8,9,10 of the Phillips prism, its air interval is 30 microns ± 10 microns, to prevent the air gap from being too small due to glass expansion during high temperature, internal reflection fail. In contrast, the air gap thickness of conventional total internal reflection prisms and Phillips prisms is about 10 microns.

FIG. 4 shows the shift of the spectral curves measured at 80° C. for the Philips prism dichroic and color-combining films 11 and 12 of the present invention. For all color separation and color combination films 11 and 12, when the temperature changes from room temperature to 80°C, the shift of the wavelength corresponding to the transmittance of 50% is less than 1nm, which ensures that the image can still be maintained when the temperature of the projector rises Color is stable. However, the drift of the conventional color-separation and color-combining film can be as large as about 20nm, which will cause serious color difference in such a system with large temperature changes, so it cannot be applied.

Claims (5)

1. A color separation and color combiner of an ultra-high-brightness digital cinema projector, characterized in that white light passes through the second total internal reflection prism (2) and Philips compensation after total reflection by the first total internal reflection prism (1) After the prism (3), the first air gap (8) of the Philips prism, and the Philips anti-red prism (4), the anti-red transparent blue-green color separation film (11) divides white light into two beams of red and blue-green light , wherein a beam of reflected red light is totally reflected by the first air gap (8) of the Philips prism, and arrives at the image chip (13) of the red light path, and another beam of transmitted blue-green light passes through the Philips anti-blue prism (5) be divided into blue and green two beams of light again by anti-blue transparent color separation film (12), wherein the blue light of a bundle of reflections is totally reflected by the second air gap (9) of the Philips prism, and reaches the blue light path image Chip (14), another bunch of transmitted green light reaches the green light path image chip (15) through the Philips green prism (6). 2. The color separation and combiner of an ultra-high brightness digital cinema projector according to claim 1, wherein the material of the prism is K9 or Schott BK7 glass. 3. the color separation and color combination device of a kind of ultra-high brightness digital cinema projector according to claim 1, is characterized in that described anti-red transparent blue-green color separation color combination film (11), anti-blue transparent green color separation color combination film (12) Ta2O5, Nb2O5 or TiO2 is used as the high refractive index film, and Al2O3 is used as the low refractive index film. 4. The color separation and combiner of an ultra-high-brightness digital cinema projector according to claim 1, wherein a heat sink is provided at the non-light-transmitting part of the prism. 5. The color separation and combiner of a super-high-brightness digital cinema projector according to claim 1, characterized in that the air gap interval of the prism interface is 20 microns to 40 microns.

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