CN101359158B - projection device - Google Patents

Abstract

The invention relates to a projection device. In the projection device, the first light source, the second light source and the third light source respectively provide a first color light, a second color light and a third color light. The first digital micro-mirror device is used for receiving and reflecting the first color light, the second digital micro-mirror device is used for receiving and reflecting the second color light and the third color light guided by the first light guide device, and then the second light guide device projects the color light from the first digital micro-mirror device and the second digital micro-mirror device.

Description

projection device

technical field

The present invention relates to a projection device, in particular to a projection device applied to a digital micromirror device and using a light emitting diode as a light source.

Background technique

Projection devices have been widely used in offices, homes and conference rooms. Among them, digital light processing projection device (Digital Light Processing, DLP) is an application of digital projection and display technology, which can accept digital signals , and then generate a column of digital light pulses. The core of DLP technology is to use a digital micromirror device (Digital Micromirror Device, DMD). When light is projected onto the DMD, it will reflect the light to the lens through multiple micromirrors on the DMD to form an image.

When the projection device uses three DMDs for the three primary colors, although it can achieve thousands of lumens of brightness and better resolution, but because the unit price of DMD is high, and it needs to cooperate with other optical components to achieve its effect, it will greatly increase the product cost. Cost; on the contrary, if the number of DMDs is reduced, although the projection device can obtain better competitiveness in terms of cost, it cannot achieve higher brightness and resolution. Therefore, a projection device with two DMDs, which has good optical efficiency and does not require excessive cost, is widely used in the industry.

An existing DLP projection device with two DMDs is shown in FIG. 1 . This projection device 1 mainly includes a light source 11, a color wheel 14, a total internal reflection (total internal reflection, TIR) prism 15, two digital micromirror devices 16a, 16b, a beam splitter 17 and a projection lens 18, wherein the light source 11 Usually an ultrahigh pressure mercury lamp (UltraHigh Pressure Lamp, UHP). Specifically, the light produced by the light source 11 passes through the color wheel 14 to form three primary colors of light, and enters the total reflection prism 15; after passing through the total reflection prism 15, the light of different colors can be separated by the beam splitter 17, and projected to two digital micromirror devices 16a respectively , 16b. Since the ultra-high pressure mercury lamp has poor performance in red light, it can be designed in accordance with the filter ratio of the color wheel 14 to increase the ratio of red light; Switching between blue and green light is also an option to obtain a more balanced three-primary color light. Then, the red light is processed by the digital micromirror device 16b alone, while the green light and the blue light share the digital micromirror device 16a, so that the effect of balancing the three primary colors can be achieved. After being respectively reflected by the digital micromirror devices 16 a and 16 b , the light rays are recombined and pass through the total reflection prism 15 to exit from the projection lens 18 .

However, in the existing DLP projection device, if the light source 11 adopts an ultra-high pressure mercury lamp, there will be many disadvantages. Since the ultra-high pressure mercury lamp needs a very high voltage to start, under this high power consumption demand, it must be driven by an AC power source, which will make the circuit more complicated; the ultra-high pressure mercury lamp generates ultraviolet rays through the excitation of mercury. Then it forms a high-brightness light source, and it takes a long time to reach a certain brightness. After starting up, the temperature of the bulb is as high as nearly 1,000 degrees Celsius, and it takes a long time to cool down after turning off the heat dissipation. Therefore, ultra-high pressure mercury is used. Lamps must have extremely high heat dissipation requirements. In addition, the use of ultra-high pressure mercury lamps still needs to cooperate with the color wheel to produce the light of the three primary colors. There are also problems such as short life, difficult replacement, insufficient color gamut, environmental pollution, power consumption, and space occupation.

To sum up, the existing projection devices using two-chip digital micromirror devices and ultra-high pressure mercury lamps are still insufficient in terms of performance, heat dissipation, and display color gamut. A two-chip DMD projection device with a wide color gamut, small size, simple structure, low cost, and short start-up time is urgently needed by the industry.

Contents of the invention

An object of the present invention is to provide a projection device, which can control three primary colors of light by using a two-chip digital micromirror device.

Another object of the present invention is to provide a projection device that uses light emitting diodes as light sources. This light source can be driven without high voltage, and has a long lifespan, easy maintenance, fast response and power saving.

Another object of the present invention is to provide a projection device, which can enhance the brightness, enhance the luminous efficiency and make the luminous flux sufficient, and can maintain the continuity of the light without being detected by naked eyes.

To achieve the above object, the projection device of the present invention includes a first light source, a second light source, a third light source, a first light guide device, a first digital micromirror device (digital micromirror device, DMD), a The second digital micromirror device and a second light guiding device. Wherein, the first light source is suitable for providing a first color light, the second light source is suitable for providing a second color light, and the third light source is suitable for providing a third color light, wherein the second color light and the third color light emit light alternately, The first light guide device is suitable for guiding the second color light and the third color light, the first digital micromirror device is suitable for receiving and reflecting the first color light, and the second digital micromirror device is used for receiving and reflecting the guided light. The second color light and the third color light, the second light guiding device is suitable for projecting the color light from the first digital micro mirror device and the second digital micro mirror device.

For example, the projection device of the present invention may include a green light emitting diode, a red light emitting diode, a blue light emitting diode, a first digital micromirror device and a second digital micromirror device, wherein the green light emitting diode is used for Provide a green light, the red light-emitting diode is used to provide a red light, the blue light-emitting diode is used to provide a blue light; the first digital micromirror device is used to receive and reflect the green light, and the second digital micromirror device is used to receive and Reflects red and blue light. Wherein, the red light emitting diode and the blue light emitting diode emit light alternately.

Description of drawings

After referring to the following description of the embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art can understand the purpose of the present invention, as well as the technical means and implementation aspects of the present invention; wherein:

FIG. 1 is a schematic diagram of an existing digital light processing projection device;

2A is a top view of the projection device according to the first embodiment of the present invention;

FIG. 2B is a three-dimensional schematic diagram of the projection device according to the first embodiment of the present invention;

3A is a bottom view of a projection device according to a second embodiment of the present invention;

3B is a top view of a projection device according to a second embodiment of the present invention; and

FIG. 4 is a schematic diagram of a heat dissipation device according to a second embodiment of the present invention.

Detailed ways

The first embodiment of the present invention provides a projection device. The top view and perspective view of the projection device 2 are shown in FIG. 2A and FIG. 2B respectively. The projection device 2 includes a first light source 201a, a second light source 201b, a third light source 201c, a first light collecting rod 203a, a second light collecting rod 203b, a third light collecting rod 203c, a first light guiding device 205, a first mirror 207a, a second mirror 207b, a first prism 209a, a second prism 209b, a first digital micromirror device (digital micromirror device, DMD) 211a, a second digital micromirror device 211b and a second light guiding device 213 .

The first light source 201a is adapted to provide a first color light, the second light source 201b is adapted to provide a second color light, and the third light source 201c is adapted to provide a third color light. In this embodiment, the first light source 201a, the second light source 201b and the third light source 201c are a green light emitting diode, a red light emitting diode and a blue light emitting diode respectively, so the first color light, the second color light and the third color light The color lights are respectively a green light, a red light and a blue light.

The above-mentioned light emitting diodes can also be arranged in multiples to form a light emitting diode array, which can be easily conceived by those with ordinary knowledge in this field, and will not be repeated here. In this embodiment, the red LED and the blue LED alternately emit light with a 50% duty cycle, while the green LED emits light continuously, that is, operates with a 100% duty cycle. The 50% duty cycle is just an example. In other embodiments, the duty cycle distribution of the red and blue LEDs can be adjusted according to requirements. For example, the red LED can emit light with a duty cycle ranging from 40% to 60%. , while the blue LED emits light with a corresponding duty cycle that is complementary to that of the red LED.

The first light collecting rod 203a, the second light collecting rod 203b and the third light collecting rod 203c are respectively adjacent to the first light source 201a, the second light source 201b and the third light source 201c, so as to uniformize and guide the light from the first light source 201a, the The first color light, the second color light and the third color light of the second light source 201b and the third light source 201c.

The first light guiding device 205 in the projection device 2 is suitable for guiding the second color light and the third color light uniformized by the second light collecting rod 203b and the third light collecting rod 203c. Preferably, the first light guiding device 205 can be a dichroic mirror.

Specifically, the first color light exited by the first light collecting column 203a successively enters the first digital micromirror device 211a through the first reflector 207a and the first prism 209a; passes through the second light collecting column 203b and the third light collecting column 203c The second color light and the third color light at the exit are first selectively guided to the second reflector 207b by the first light guiding device 205, and then pass through the second reflector 207b and the second prism 209b successively, and then enter the In the second digital micromirror device 211b.

As above, the first digital micromirror device 211a receives the first color light and reflects it to enter the first prism 209a again, while the second digital micromirror device 211b receives the second color light and the third color light and reflects it to Enter the second prism 209b again. The first prism 209 a and the second prism 209 b guide the above-mentioned colored light into the second light guiding device 213 . Preferably, both the first prism 209a and the second prism 209b are total internal reflection (TIR) prisms.

The second light guiding device 213 is adapted to combine the color lights guided by the first prism 209a and the second prism 209b, and after the image is combined, it can be sent to the projection lens group 20 of the projection device 2 to be projected onto the screen (Fig. not shown). In this embodiment, the second light guiding device 213 is preferably a dichroic cube, for example, the dichroic cube can be a Philips prism.

The second embodiment of the present invention also provides a projection device, the top view and bottom view of which are shown in FIG. 3A and FIG. 3B respectively. In addition to all the elements of the previous embodiment, the projection device 3 also includes a heat sink 31 to dissipate heat.

In order to match the number of light sources, the heat sink 31 of this embodiment can have three heat conducting plates 311a, 311b, 311c, three heat conducting units and multiple heat sinks 315, and the three heat conducting units described in this embodiment can be They are respectively heat pipes (heat pipe) 313a, 313b, 313c. As shown in FIG. 4, taking the first light source 301a, the corresponding heat conducting plate 311a, the plurality of cooling fins 315 and the heat pipe 313a as an example, in order to conduct heat effectively, the heat conducting plate 311a is thermally connected with the first light source 301a, and the heat pipe Both ends of 313a are also thermally connected to the heat conducting plate 311a and the heat dissipation fins 315 respectively. In this way, the heat transferred from the contacted first light source 301a to the heat conducting plate 311a can be guided to the heat dissipation fins 315 through the heat pipe 313a to dissipate to the outside.

Please refer to FIGS. 3A and 3B again. In this embodiment, these light sources 301a-301b are arranged on the same side as the projection lens group 20, and each of the heat pipes 313a, 313b, 313c extends toward the same side, and the heat dissipation fins are also arranged on the same side. The heat pipes 313 a , 313 b , 313 c are arranged on the same side, in other words, the heat pipes 313 a , 313 b , 313 c extend toward the cooling fins 315 . The above configuration can save the volume size of the projection device, and can effectively separate the heat dissipation area from the optical area, which can prevent the heat energy from affecting each optical element, and can effectively increase the heat dissipation efficiency by concentrating and discharging the heat.

Referring to the above-mentioned embodiments, it can be known that the light sources are not limited to the light emitting diodes, and the colors of the light emitting diodes are not limited as above. In addition, it should be noted that each of the light sources 301a-301c can also be integrated with the cooling device 31 into a component (not shown in the figure), so that the component can be detachably arranged in the projection device 3, and this embodiment is also a part of the present invention. The concept to be expressed. The types, positions and quantities of the optical elements in the above embodiments are only used to illustrate the present invention, and those skilled in the art can easily deduce other implementations.

The two-chip digital light processing projection device of the present invention can use light-emitting diodes as light sources. Wide range of color gamut; short start-up time, can achieve fast start-up or shutdown, so that after the light source is extinguished, the waiting time for shutdown can also be greatly shortened, and there will be no problem of mercury pollution. In addition, the setting of the color wheel and other optical components can be omitted, so the overall size of the lighting system can be greatly reduced, the system structure can be simplified, and the manufacturing cost of the projection device can be reduced. Therefore, the two-chip digital light processing projection device adopting the architecture of the present invention can greatly improve its color display, imaging brightness, and efficiency.

The above-mentioned embodiments are only used to illustrate the implementation of the present invention and explain the technical features of the present invention, and are not intended to limit the scope of the present invention. Any changes or equivalence arrangements that can be easily accomplished by those skilled in the art fall within the scope of the present invention, and the protection scope of the present invention should be based on the scope of claims in this application.

Claims (27)

1. A projection device, characterized in that it comprises: a first light source adapted to provide a first color light; a second light source adapted to provide a second color light; a third light source, adapted to provide a third color light, wherein the second color light and the third color light emit light alternately; a first light guiding device adapted to guide the second colored light and the third colored light; A first digital micromirror device, suitable for receiving and reflecting the first color light; a second digital micromirror device for receiving and reflecting the guided second color light and the third color light; and A second light guiding device is adapted to project the colored light from the first DMD and the second DMD. 2. The projection device according to claim 1, further comprising a first prism and a second prism, the first prism is arranged between the first digital micromirror device and the second light guiding device , and the second prism is disposed between the second digital micromirror device and the second light guiding device. 3. The projection device according to claim 2, wherein each of the first prism and the second prism is a total internal reflection prism. 4. The projection device according to claim 1, wherein the first light guiding device is a beam splitter. 5. The projection device according to claim 1, wherein the second light guiding device is a light splitting element. 6. The projection device according to claim 1, further comprising a first light collecting rod, a second light collecting rod and a third light collecting rod, which are respectively adjacent to the first light source, the second light source and the The third light source is used to uniformize the first color light, the second color light and the third color light from the first light source, the second light source and the third light source respectively. 7. The projection device according to claim 1, wherein the third color light emits light at a duty cycle that is complementary to that of the second color light, and each of the second color light and the third color light is 40% to 60% % of a duty cycle alternately emits light. 8. The projection device according to claim 1, further comprising a heat dissipation device having: a heat conducting plate in contact with at least one of the light sources; at least one cooling fin; and a heat conduction unit connected to the heat conduction plate and the at least one heat dissipation fin; Thereby, the heat transferred from the light source to the heat conducting plate is guided to the at least one heat dissipation fin. 9. The projection device according to claim 1, further comprising a heat dissipation device having: Three heat conducting plates, which are in contact with these light sources respectively; a plurality of cooling fins; and Three heat conduction units are respectively connected to these heat conduction plates and these heat dissipation fins; Thereby, the heat transferred from the light sources to the heat conducting plates is directed to the heat dissipation fins. 10 . The projection device according to claim 9 , wherein the heat dissipation fins are disposed on the same side, and each heat conduction unit extends toward the heat dissipation fins and is thermally connected with the heat dissipation fins. 11 . 11. The projection device according to claim 8 or 9, wherein each of the heat conducting plates is a copper sheet. 12. The projection device according to claim 8 or 9, wherein each heat conduction unit is a heat pipe. 13. The projection device according to claim 8 or 9, wherein each of the cooling fins is made of copper or aluminum. 14. A projection device, characterized in that it comprises: a green light emitting diode for providing a green light; a red light emitting diode for providing a red light; a blue light-emitting diode for providing a blue light; A first digital micromirror device, which is used to receive and reflect the green light; and a second digital micromirror device for receiving and reflecting the red light and the blue light; Wherein, the red light emitting diode and the blue light emitting diode emit light alternately. 15. The projection device according to claim 14, further comprising a first prism and a second prism, the first prism guides and enables the first DMD to receive the green light, the second prism The prism guides and makes the second DMD receive the red light and the blue light. 16. The projection device according to claim 15, wherein each of the first prism and the second prism is a total internal reflection prism. 17. The projection device according to claim 15, further comprising a spectroscopic element, the green light reflected by the first digital micromirror device and the red light reflected by the second digital micromirror device are combined with the The blue light is respectively guided to the light splitting element by the first prism and the second prism, and then projected out. 18. The projection device according to claim 14, further comprising a first light-collecting rod, a second light-collecting rod and a third light-collecting rod, which are respectively adjacent to the green light-emitting diode, the red light-emitting diode and the The blue LED is used to uniformize the green light, the red light and the blue light respectively. 19. The projection device according to claim 18, further comprising a dichroic mirror for guiding the red light from the second light collecting rod and the blue light from the third light collecting rod. 20. The projection device according to claim 14, wherein the blue LED emits light at a duty cycle corresponding to that of the red LED, and each of the red LED and the blue LED emits light at a duty cycle of 40% to 60% % of the duty cycle alternately glows. 21. The projection device according to claim 14, further comprising a heat dissipation device having: a heat conducting plate in contact with at least one of the LEDs; at least one cooling fin; and a heat conduction unit connected to the heat conduction plate and the at least one heat dissipation fin; Thereby, the heat transferred from the light emitting diode to the heat conduction plate is guided to the at least one heat dissipation fin. 22. The projection device according to claim 14, further comprising a heat dissipation device having: Three heat conducting plates, which are respectively in contact with the light emitting diodes; a plurality of cooling fins; and Three heat conduction units, which are respectively connected to the heat conduction plates and the heat dissipation fins; Thereby, the heat transferred from the light emitting diodes to the heat conducting plates is directed to the heat dissipation fins. 23. The projection device according to claim 22, wherein the heat dissipation fins are disposed on the same side, and each heat conduction unit extends toward the heat dissipation fins and is thermally connected with the heat dissipation fins. 24. The projection device according to claim 21 or 22, wherein each of the heat conducting plates is a copper sheet. 25. The projection device according to claim 21 or 22, wherein each heat conduction unit is a heat pipe. 26. The projection device according to claim 21 or 22, wherein each of the cooling fins is made of aluminum sheet. 27. The projection device according to claim 21 or 22, wherein at least one of the light emitting diodes and the heat dissipation device are an assembly, and the assembly is detachably arranged in the projection device.

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