TWI476447B - Stereoscopic projection display apparatus - Google Patents

Description

Stereo projection display device

The present invention relates to an optical projection display device that can produce a stereoscopic image. It can be applied to the design of an optical system of a projector that must use polarized glasses to view stereoscopic images.

With the rapid development of technology, people's quality of life has gradually increased, and the demand for consumer electronic products is increasing. Due to the box office sales of 3D stereoscopic movies, the global stereoscopic display industry is booming, and 3D stereo projectors are no exception.

The human eye perceives stereoscopic vision, mainly caused by binocular parallax and motion parallax. After receiving different images through both eyes, the brain combines the two images to form a stereoscopic picture. Among them, the parallax of the two eyes is due to the position of the left eye and the right eye of the human being. The average distance between the two eyes is about 6 to 6.5 cm, which causes the visual angle of the two eyes to be slightly different when viewing the object, so the eyes The images received will also be different. The mobile parallax means that when the viewer watches the same object while moving, the viewing angle of the two eyes viewing the object changes with the movement of the viewer, and the image content received by the eye also changes.

In recent years, due to the more diversified use of stereoscopic images, the rapid take-off and improvement of 3D display technology has been promoted. However, how to improve the comfort of viewing stereoscopic display, reduce the cost of the stereoscopic display, and reduce the volume of the stereoscopic display system are all important development goals of the current 3D stereoscopic display technology.

The development of 3D stereoscopic display technology is based on the principle of stereoscopic vision. Using different spectroscopic techniques, the two eyes respectively receive different images to form a stereoscopic effect. For example, the early red and blue glasses use red and blue filter lenses. The images of different viewing angles are filtered and sent to the left and right eyes respectively to achieve the image content of different viewing angles of the left eye and the right eye respectively and the stereoscopic effect is felt.

After a long period of development and evolution, 3D stereoscopic display technology can be roughly divided into two categories: one is glasses-type stereoscopic display technology, and the other is autostereoscopic stereoscopic display technology without glasses. "." The glasses-type stereoscopic display technology, which was first developed, has matured to the present, and it is comparable to the naked-eye stereoscopic display technology that has not been developed in recent years, both in terms of display size and stereoscopic effect.

Among the many stereoscopic display technologies that need to wear glasses, the image quality and stereoscopic effect of the polarized glasses stereoscopic projection display system are the most dominant. However, such a system requires two projectors to respectively project different images corresponding to the left and right eyes with mutually perpendicularly polarized beams, so that the left and right glasses can respectively pass the beams of the corresponding polarization directions to obtain a three-dimensional image. effect. Therefore, the space and components required for the system are relatively large and complex.

Please refer to "FIG. 1", which is a conventional architecture of the polarized glasses stereoscopic projection display system 10. The polarized glasses stereoscopic projection display system 10 basically comprises two projectors, namely a projector 11a for projecting a left eye image and a projector 11b for projecting a right eye image, wherein the two projectors 11a and 11b each have a lighting system. 12a and 12b, optical engines 13a and 13b, and projection lenses 14a and 14b. The two projectors 11a and 11b respectively project the left and right eye images through the projection lenses 14a and 14b through the two polarizers 15a and 15b whose polarization directions are perpendicular to each other to project the beams perpendicular to each other in the polarization direction to have a retention bias. The special polarization of the polarization characteristics is retained on the polarization reserved screen 16. The left and right eye image beams retain their polarization characteristics perpendicular to each other after being reflected by the polarization-retaining screen 16.

Referring to "Fig. 2", the application of the polarized glasses 20 as the polarizing plate 15 is composed of two polarizing plates 15a and 15b whose polarization directions are perpendicular to each other, in order to make the polarized film After the reflection of the screen 16 remains, the beam 24 of the left-eye image 21 and the beam 25 of the right-eye image 22, which have polarization directions perpendicular to each other, can respectively enter the left and right glasses of the corresponding polarization direction, thereby achieving the left and right eyes. Go to different images to present the perceived effect of the 3D stereo image 23.

As described in the prior art, a polarized glasses stereoscopic projection display system is to be realized. 10, two projectors must be used to project two image beams with mutually perpendicular polarization, so the space and components required by the system are relatively large and complex, and it is difficult to develop in the direction of miniaturization. Therefore, if the two projectors can be integrated into one, the effect of stereoscopic projection display can be realized by a single projector, and the number of components of the optomechanical engine can be reduced, and the shortcomings of the conventional technology can be greatly improved, which is an important feature of the stereoscopic display industry. Research development and the direction of innovative design.

In order to solve the conventional polarized glasses stereoscopic projection display system 10, the present invention requires two projectors to project two image beams that are vertically polarized. We propose a basic design of a optomechanical engine with a concept similar to the optical path architecture of the Mach-Zehnder interferometer as a stereoscopic projection display device, and with a polarization beam splitter (PBS), a single illumination system The emitted beam is split into two mutually perpendicular polarized beams, which are respectively incident on a digital micromirror device (DMD) that replaces the two mirrors in the McKenzie interferometer, and through the element The reflection brings out the different images of the two left and right eyes, and combines the two beams again with a polarized beam splitter, and finally projects onto the screen with a single projection lens to produce a stereoscopic image. Although the design concept of the stereoscopic projection display device using the McKenzie interferometer optical path architecture is not first seen in the present invention, the design of the stereoscopic projector using the concept of the McKenz interferometer has been proposed in the US Patent No. 512,1983. The patent faithfully uses the optical path of the interferometer of Michael, and still uses two general mirrors and two beamsplitters in the optical path. Only two penetrating liquid crystal elements are added in front of the second beam splitter at the junction of the two optical paths (liquid Crystal device, LCD) to carry two different images. The invention is only applicable to projection systems employing liquid crystal elements. However, in general, a liquid crystal element is used as a light-modulating planar projection system, and most of them must use three liquid crystal elements to display the color effect, otherwise the high resolution and high brightness cannot be achieved. Therefore, according to this patent, in order to realize the effect of stereoscopic projection, it is necessary to have three sets of the same structure, that is, six liquid crystal elements can be realized, which is a test of the realization of the system, not to mention the development of the micro-portable type. . In addition, there are The new patent of the Republic of China M374590U1 uses the optical path architecture of the Michelson interferometer with a two-reflective image unit to realize the concept of stereoscopic projection display. However, the concept must place a quarter wave in front of the two image units. Plate, QWP) to rotate the direction of the beam back and forth by 90 degrees, otherwise a single polarization beam splitter cannot be used for polarization splitting. Generally, a quarter-wave plate is only suitable for a single wavelength, which is not practical for a projection system that is applied in the full range of visible light.

The main feature of this creation is to simplify the two projection systems into a single projection architecture, using only a single illumination system and a single projection lens, splitting and merging the beams through a polarizing beam splitter, and replacing the microphone with a digital micro-mirror element. The general mirror of the Mori architecture can project two different images onto the screen for stereoscopic projection display. The authoring structure is simple, the number of components is small, and it is easy to reduce the size, and has the important feature of miniaturization.

The details and techniques of the present invention are described below in conjunction with the drawings:

Please refer to "FIG. 3", which is a schematic diagram of the principle of the polarization beam splitter 30. The function of the polarization beam splitter 30 is to have different reflection or penetration characteristics for incident light of different polarization directions. In the present creation, the main purpose of the element is to reflect and penetrate the vertical polarization (S-polarization) component 24 and the horizontal polarization (P-polarization) component 25 of the general beam 31 without a specific polarization direction. Separation. After the splitting, in addition to the absorption of the component itself, the intensity of the original incident beam can be substantially completely retained, and thus the light utilization efficiency is better.

Please refer to FIG. 4, which is a basic architecture diagram of the Michael J. Interferometer 40 referenced by the creation of the present invention. The laser beam 41 is used as a light source, and the incident beam 41 is divided into data by the first beam splitter 42a. An information beam 43 and a reference beam 44, the two beams are respectively reflected by the two mirrors 45a and 45b, and are again combined at the second beam splitter 42b, through interference (interference, finally Interference fringes are generated at the photodetector 46.

Please refer to "figure 5", which illustrates a specific embodiment of the creation of the present invention. In order to make the single illumination system provide two polarized beams with mutually perpendicular polarization directions to project the left and right eye images, the creation of the optical path concept of the Michael K. Interferometer 40 as the projector optomechanical machine is referred to in the fourth drawing. The engine's infrastructure, and its beamsplitters 42a and 42b are replaced by polarized beamsplitters 30a and 30b to obtain the splitting and combining of the polarized beams. First, the light beam emitted from the light source 51 without a specific polarization direction is collected by a condenser 52, passed through a color wheel 53, and incident on the polarization beam splitter 30a via a collimator 54. The light beam of a specific polarization direction includes a vertical polarization component 24 and a horizontal polarization component 25, and enters the first polarization beam splitter 30a, wherein the vertical polarization component 24 is reflected by the polarization beam splitter 30a, and The horizontal polarization component 25 then penetrates the polarization beam splitter 30a. The mirrors 45a and 45b in the McGenz interferometer architecture are replaced by two-digit micromirror elements 50a and 50b, in addition to providing reflections for the respective vertical polarization component 24 and horizontal polarization component 25 beams. In addition to the effect of the steering, the left and right eye images presented on the digital micromirror elements 50a and 50b are simultaneously taken out after the reflection. The two polarized images after the two reflections are respectively transmitted to the second polarization beam splitter 30b, and the different polarization components are reflected and penetrated into a single layer according to the same action of the polarization beam splitter 30a. After the beam, it is finally projected onto the polarization preserved screen 16 via a single projection lens 14 in a single path.

The design of the stereoscopic projection display device is composed of two parts, namely a projector illumination system 55 and a projection system 56. In the illumination system 55, a high-pressure mercury lamp is generally used as the light source 51, and the divergent light emitted from the bulb is converted into parallel light by the parabolic lampshade into the condensing mirror 52, the beam is focused on the color wheel 53, and the beam is changed according to the color change of the image. The components are sequentially filtered into red, green or blue light, and the beams are collected by the collimating mirror 54 and uniformly incident on the projection system 56.

In the projection system 56, when the parallel beam entering the optomechanical engine splits the beam into the reflected vertical polarization component 24 and the penetrating horizontal polarization component 25 via the first polarization beam splitter 30a, respectively The digital micromirror elements 50a and 50b outputting the left and right eye images are reflected to carry the vertical polarization component 24 In the left eye image, the horizontal polarization component 25 carries the right eye image, and then the vertical polarization component 24 and the horizontal polarization component 25 are combined by the second polarization beam splitter 30b, and finally passed through a The set of projection lenses 14 magnify and project the image onto the polarization preserved screen 16 to present a stereoscopic image.

Since the light component of different colors is filtered by the single color wheel 53 in this embodiment, the two-digit micromirror elements 50a and 50b are incident on the polarized beam splitter 30a, so that the driving of the two-digit micromirror elements 50a and 50b must be Synchronizing with the color wheel 53 to cause the beams of the same color to be simultaneously reflected by the micro-mirrors 60 on the two different micro-mirror elements.

The digital micromirror device 50 is a digital imaging device made by microelectromechanical technology, and the inside thereof is composed of a plurality of micromirrors 60 of a two-dimensional array, driven by a digital micromirror device 50, each micro The mirror 60 has a rotation angle of ±12 degrees. When the image output is a bright point, the micro mirror 60 is rotated by -12 degrees, which is called an on state. This state causes the micro mirror 60 to reflect the light source into the projection lens. As the projection display of the image; when the micro mirror 60 is rotated by +12 degrees, it is called an off state, and the light source reflected by the micro mirror 60 is received by the light absorber and cannot enter the projection lens. , the image is output as a dark spot. Therefore, in the placement of the components, it is necessary to take into account the ±12 degree rotation angle of the digital micromirror element 50 itself. In order to make the vertically polarized light 24 and the horizontally polarized light 25 incident in the same state as the two-digit micromirror elements 50a and 50b, the first digital micromirror element 50a must be compared with the second digital micro-image. The mirror element 50b is flipped 180 degrees so that the relative angles of the vertically polarized light 24 and the horizontally polarized light 25 reflected by the two digital micromirror elements 50a and 50b remain the same.

Since the first digital micromirror element 50a is flipped by 180 degrees, the two polarized beams split from the first polarizing beam splitter 30a are from the first digital micromirror element 50a and the second. The left side of the sheet-count micromirror element 50b is incident, so that the tilt angles required for the two-digit micromirror elements 50a and 50b are the same.

Referring to "Fig. 6a", when the digital micromirror element 50b is placed at an angle of 45 degrees, the micromirror 60 thereon reflects the incident beam 61 at a 66 degree angle in the on state, causing the reflected beam 62 to deviate. The optical axis that should be incident on the second polarization beam splitter 30b has a difference of 24 degrees. Therefore, if the light beam can be accurately reflected by the digital micromirror device 50b at 90 degrees and correctly incident on the second polarization beam splitter 30b, It needs to be obtained by the optical lever formula, as follows: ω=2 In the formula The angle at which the digital micromirror element 50b should be rotated, ω is the angle at which the reflected light deviates from the optical axis of the incident second polarizing beam splitter 30b. Please refer to "Fig. 6b" and substitute ω = 24 degrees into the above equation to obtain the angle at which the digital micromirror device 50b needs to be rotated. It is 12 degrees, so the inclination angle of the digital micromirror element 50b is 45 + 12 = 57 degrees. The same discussion applies to the placement of another digital micromirror element 50a.

The foregoing description of the angle of the micro-mirror element 50 is not limited by the specific angle value. The different factors or product categories of the cover factor micro-mirror element 50 may cause different angles, but the principle of the arrangement Still not out of the spirit of this note. In addition, the two different polarizations of the MacKan scored optical architecture are not limited to a 90 degree vertical path placement.

According to the basic spirit of the present invention, in addition to exposing the design structure of the stereoscopic projection display device, the design architecture can be promoted to various stereoscopic display related applications without being limited by the use of the projection system.

While the invention has been described above in terms of a preferred embodiment, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

10‧‧‧Polarized glasses stereo projection system

11‧‧‧Flat projector

10a‧‧‧Projector for Projecting Left Eye Image 1

10b‧‧‧Projector 2 projecting right eye image 2

12‧‧‧Lighting system

12a‧‧‧Lighting system of projector 1

12b‧‧‧Projector 2 lighting system

13‧‧‧optical engine

13a‧‧‧Projector 1 optomechanical engine

13b‧‧‧Projector 2 optomechanical engine

14‧‧‧Projection lens

14a‧‧·Projection lens of projector 1

14b‧‧·Projector 2 projection lens

15‧‧‧polarizer

15a‧‧‧Vertical Polarization

15b‧‧‧Horizontal Polarizer

16‧‧‧Polarization reserved screen

20‧‧‧Polarized glasses

21‧‧‧ Left eye image

22‧‧‧right eye image

23‧‧‧3D stereo image

24‧‧‧S-polarization

25‧‧‧Horizontal polarized light (P-polarization)

30‧‧‧Polarizing Beamsplitter

30a‧‧‧Polarizing Beamsplitter 1

30b‧‧‧Polarizing Beamsplitter 2

31‧‧‧General beam

40‧‧‧Mach-Zehnder interferometer

41‧‧‧Laser incident beam

42‧‧‧beamscope (beamspillter)

42a‧‧‧beam splitter 1

42b‧‧‧beam splitter 2

43‧‧‧Information beam

44‧‧‧reference beam

45‧‧‧Mirror

45a‧‧‧Mirror 1

45b‧‧‧Mirror 2

46‧‧‧Photodetector

50‧‧‧Digital micromirror components

50a‧‧‧Digital mirror element 1

50b‧‧‧Digital Mirror Element 2

51‧‧‧Light source

52‧‧‧Condenser

53‧‧‧color wheel

54‧‧‧collimator

55‧‧‧Lighting system

56‧‧‧Projection system

60‧‧‧micro mirror

61‧‧‧ incident beam

62‧‧‧Reflected beam

FIG. 1 is a schematic diagram showing the basic structure of a conventional polarized glasses stereoscopic projection system.

Figure 2 is a schematic diagram of the principle of polarized glasses stereoscopic display.

Figure 3 is a schematic diagram of the operation principle of the polarization beam splitter.

Figure 4 is a schematic diagram of the architecture of the McKenz interferometer referenced by the author.

Figure 5 is a schematic view showing the structure of a specific embodiment of the present invention.

Fig. 6a is a schematic view showing the light reflection of the digital micromirror element when the tilt angle is 45 degrees in the specific embodiment of the present invention.

Fig. 6b is a schematic view showing the light reflection of the digital micromirror device when the tilt angle is 57 degrees in the specific embodiment of the present invention.

14‧‧‧Projection lens

16‧‧‧Polarization reserved screen

24‧‧‧S-polarization

25‧‧‧Horizontal polarized light (P-polarization)

30a‧‧‧Polarizing Beamsplitter 1

30b‧‧‧Polarizing Beamsplitter 2

50a‧‧‧Digital mirror element 1

50b‧‧‧Digital Mirror Element 2

51‧‧‧Light source

52‧‧‧Condenser

53‧‧‧color wheel

54‧‧‧collimator

55‧‧‧Lighting system

56‧‧‧Projection system

Claims (6)

A stereoscopic projection display device uses a single illumination system to project two mutually perpendicular polarized beams into two digital micromirror elements having left and right eye images according to the polarization characteristics of the light, and through a single Projection lens, projecting two images onto the same screen to obtain the effect of polarized glasses stereoscopic projection display, comprising: an illumination system for providing a projection beam without a specific polarization direction, by a light source, a condensing mirror, a color wheel And a collimating mirror; the first polarizing beam splitter is configured to split the beam incident by the illumination system into a reflected beam and a penetrating beam which are perpendicular to each other in the two polarization directions; the first digital micromirror element is used for The polarized light beam reflected by the first polarizing beam splitter is further reflected, and the light beam is reflected to carry the first image from the first digital micromirror element; the second digital micro mirror element , the polarized light beam that penetrates the first polarizing beam splitter is reflected again, and the light beam is reflected and then the second image is carried out from the second digital micromirror element; the second polarized pole a beam splitter for reflecting the polarized light beam reflected by the first digital micromirror element and transmitting the polarized light beam reflected by the second digital micro mirror element, and the polarization directions are perpendicular to each other The beams are then combined into the same direction of propagation and carry two different images; a projection lens is used to project the two different image beams combined by the second polarization beam splitter onto the same screen. The stereoscopic projection display device of claim 1, wherein the first digital micromirror element and the second digital micromirror element are placed at a position where the two reflecting surfaces are at an angle of 180 degrees to each other. The stereoscopic projection display device according to claim 1, wherein the color wheel has red, green and blue filter lenses, and the rotation frequency thereof must be synchronized with the control of the two-digit micromirror device. The stereoscopic projection display device of claim 1, wherein the first polarization beam splitter and the second polarization beam splitter may have similar spectral characteristics. That is, the vertical polarized beam has a similar transmittance and reflectance to the horizontally polarized beam. The stereoscopic projection display device of claim 1, wherein the first polarization beam splitter and the second polarization beam splitter may have opposite splitting characteristics, that is, a vertically polarized beam and a horizontally polarized beam. There is opposite penetration and reflectivity. A stereoscopic projection display device uses a single illumination system to project two mutually perpendicular polarized beams into two digital micromirror elements having left and right eye images according to the polarization characteristics of the light, and through a single Projection lens, projecting two images onto the same screen to obtain the effect of polarized glasses stereoscopic projection display, comprising: an illumination system for providing a projection beam without a specific polarization direction, by a light source, a condensing mirror, a color wheel And a collimating mirror; the first polarizing beam splitter is configured to split the beam incident by the illumination system into a reflected beam and a penetrating beam which are perpendicular to each other in the two polarization directions; the first digital micromirror element is used for The polarized light beam reflected by the first polarizing beam splitter is further reflected, and the light beam is reflected to carry the first image from the first digital micromirror element; the second digital micro mirror element , the polarized light beam that penetrates the first polarizing beam splitter is reflected again, and the light beam is reflected and then the second image is carried out from the second digital micromirror element; the second polarized pole a beam splitter for reflecting the polarized light beam reflected by the second digital micromirror element and causing the polarized light beam reflected by the first digital micromirror element to penetrate, and the polarization directions are perpendicular to each other The beams are then combined into the same direction of propagation and carry two different images; a projection lens is used to project the two different image beams combined by the second polarization beam splitter onto the same screen.