Projection device

Abstract

To provide a projection device.SOLUTION: The projection device includes a first display, a second display, a third display, a light mixing module, a first angle selector, a second angle selector, a third angle selector, and a projection lens. The first display, the second display, and the third display are respectively used to provide a first image beam, a second image beam, and a third image beam. The projection lens is disposed on a side of a light-outgoing surface of the light mixing module, and is used to project the first image beam, the second image beam, and the third image beam outside the projection device. The first image beam, the second image beam, and the third image beam respectively pass through the first angle selector, the second angle selector, and the third angle selector, and then propagates to the projection lens by the light-mixing module. The present invention can effectively reduce stray light propagating to the outside of the projection device by the light mixing module and increase contrast of a projection screen.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical device, and more particularly to a projection device.

Background Art

[0002] The light source device required for a three-color light mixing projector of a light valve system using a Digital Light Processor (DLP) or LCoS (Liquid Crystal On Silicon) has a very large volume because it has a complex optical system. In contrast, the advantage of using a combination of a three-chip micro light emitting diode display panel (micro LED panel) and a light mixing system is that the volume of the projection device can be reduced.

[0003] However, the biggest problem when using a combination of a three-chip micro light emitting diode display panel and a light mixing system is that the emission angle of the micro light emitting diode is large. As a method of reducing the angle, there is one that adds a reflector and uses a micro light emitting diode array (i.e., a micro optical array), but the limit for reducing the emission half angle is only 20 degrees (under the condition of a pixel size of less than 5 microns (μm)). In addition, when the reduction of the emission angle is limited, the emission half angle is large and total reflection occurs inside the light mixing system (light larger than the angle of effective light is totally reflected only inside the light mixing module), so that ineffective light is introduced into the projection lens, which may cause stray light to appear on the projection screen and affect the contrast of the projection screen.

[0004] Note that this "Background Art" section is only for helping to understand the content of the present invention, so the content disclosed in this "Background Art" section may include technologies unknown to those skilled in the art. Therefore, the content disclosed in this "Background Art" section does not mean that the content, or the problems to be solved by one or more embodiments of the present invention, have already been well known to those skilled in the art before the filing of the present invention.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a projection device that can reduce stray light propagating outside the projection device by an optical mixing module and effectively increase the contrast of a projection screen.

[0006] Other objects and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

Means for Solving the Problems

[0007] According to an embodiment of the present invention, a projection device is provided, which includes a first display, a second display, a third display, an optical mixing module, a first angle selector, a second angle selector, a third angle selector, and a projection lens. The first display, the second display, and the third display are respectively used to provide a first video light beam, a second video light beam, and a third video light beam. The optical mixing module has a first light incident surface, a second light incident surface, a third light incident surface, and a light exit surface (light extraction surface). The first angle selector is installed between the first display and the optical mixing module. The second angle selector is installed between the second display and the optical mixing module. The third angle selector is installed between the third display and the optical mixing module. The projection lens is installed on the light exit surface side of the optical mixing module and is used to project the first video light beam, the second video light beam, and the third video light beam outside the projection device. The first video light beam, the second video light beam, and the third video light beam respectively pass through the first angle selector, the second angle selector, and the third angle selector, and then propagate to the projection lens by the optical mixing module.

[0008] As described above, in an embodiment of the present invention, since the projection device is provided with the first angle selector, the second angle selector, and the third angle selector, the stray light of the projection device can be effectively reduced, and the contrast of the projection screen can be made relatively high.

[0009] In order to make the above-described features and advantages of the present invention more apparent, the following examples will be given and described in detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] The above and other technical contents, features, functions, and effects of the present invention will become clear from the following detailed description in the following preferred embodiments based on the accompanying drawings. Note that terms regarding directions mentioned in the following embodiments, such as up, down, left, right, front, rear, etc., are only in the directions of the accompanying drawings. Therefore, the terms of directions used are only for explaining the present invention and are not for limiting the present invention.

[0012] FIG. 1 is a diagram showing a projection device according to an embodiment of the invention. As shown in FIG. 1, according to an embodiment of the present invention, a projection device 10 is provided, which includes a first display 110, a second display 120, a third display 130, a light mixing module 200, a first angle selector 310, a second angle selector 320, a third angle selector 330, and a projection lens 400.

[0013] In this embodiment, the first display 110, the second display 120, and the third display 130 can be a liquid crystal display panel, a light-emitting diode display panel (LED display panel), a mini light-emitting diode display panel (mini LED display panel), or a micro light-emitting diode display panel (Micro LED display panel), but the present invention is not limited thereto.

[0014] In this embodiment, the light mixing module 200 is, for example, a light mixing prism (X-Cube) formed by joining four prisms, and the refractive index of its adhesive is preferably the same as that of the prism. Note that the light mixing module 200 is not limited to such a manufacturing method. Among them, an optical film can be installed on the surfaces of every two adjacent prisms (the installation method is, for example, coating). Thereby, among the video light beams propagating on the prism surface, the light beams having a specific wavelength can be reflected, and the remaining video light beams within another wavelength range can be passed through the prism surface.

[0015] In this embodiment, the first angle selector 310, the second angle selector 320, and the third angle selector 330 may be optical thin films formed by a high and low refractive index (layer) stack.

[0016] In this embodiment, the projection lens 400 is, for example, a combination of one or more optical lenses having refractive power. The optical lenses can include various combinations of non-planar lenses such as biconcave lenses, biconvex lenses, convex-concave lenses, concave-convex lenses, plano-convex lenses, and plano-concave lenses. Note that the present invention does not limit the form and type of the projection lens 400.

[0017] Specifically, the first display 110, the second display 120, and the third display 130 of this embodiment are each used to provide a first video light beam R, a second video light beam G, and a third video light beam B. The first video light beam R is, for example, a red video light beam, the second video light beam G is, for example, a green video light beam, and the third video light beam B is, for example, a blue video light beam, but the present invention is not limited thereto.

[0018] In this embodiment, the light mixing module 200 has a first light incident surface 210, a second light incident surface 220, a third light incident surface 230, and a light exit surface 240. The first light incident surface 210 faces the third light incident surface 230, the second light incident surface 220 faces the light exit surface 240, and the second light incident surface 220 is and the third light incident surface 230 to connected. The first angle selector 310 is connected between the first display 110 and the light mixing module 200. The second angle selector 320 is installed between the second display 120 and the light mixing module 200. The third angle selector 330 is installed between the third display 130 and the light mixing module 200. Among them, the first angle selector 310, the second angle selector 320, and the third angle selector 330 are respectively installed on the sides of the first light incident surface 210, the second light incident surface 220, and the third light incident surface 230 of the light mixing module 200.

[0019] In this embodiment, after the first video light beam R, the second video light beam G, and the third video light beam B pass through the first angle selector 310, the second angle selector 320, and the third angle selector 330 respectively, they can propagate to the projection lens 400 through the light mixing of the light mixing module 200. The projection lens 400 is installed on the side of the light-emitting surface 240 of the light mixing module 200 and is used to project the first video light beam R, the second video light beam G, and the third video light beam B outside the projection device 10. Among them, the first video light beam R is reflected to the projection lens 400 by the optical film of the light mixing module 200 having the function of reflecting the red light wavelength band, the second video light beam G is passed through the light mixing module 200 and propagated to the projection lens 400, and the third video light beam B is reflected to the projection lens 400 by the optical film of the light mixing module 200 having the function of reflecting the blue light wavelength band. Note that these two optical films are installed in an X-type configuration.

[0020] In this embodiment, the first angle selector 310 is a filter (band pass filter), for example, a red light wavelength filter. For example, when light is incident perpendicularly on the first angle selector 310, light with a wavelength within the range of 610 - 650 nanometers is passed through, and light with the remaining wavelengths is reflected. Also, the first angle selector 310 passes light with an incident angle smaller than 30 degrees and reflects light with an incident angle of 30 degrees or more.

[0021] In this embodiment, the second angle selector 320 is a filter, for example, a green light wavelength filter. For example, when light is incident perpendicularly on the second angle selector 320, light with a wavelength within the range of 510 - 550 nanometers is passed through, and light with the remaining wavelengths is reflected. Also, the second angle selector 320 passes light with an incident angle smaller than 30 degrees and reflects light with an incident angle of 30 degrees or more.

[0022] In this embodiment, the third angle selector 330 is a filter, for example, a blue light wavelength filter. For example, when light is incident perpendicularly on the third angle selector 330, light with a wavelength within the range of 400 to 465 nanometers is allowed to pass through, and light with the remaining wavelengths is reflected, or, for example, light with a wavelength of 465 nanometers or less is allowed to pass through, and light with the remaining wavelengths is reflected. Also, the third angle selector 330 allows light with an incident angle less than 30 degrees to pass through, and reflects light with an incident angle of 30 degrees or more.

[0023] In this embodiment, the projection device 10 further includes a first anti-reflection layer (anti-reflection layer) 510, a second anti-reflection layer 520, and a third anti-reflection layer 530. The first anti-reflection layer 510, the second anti-reflection layer 520, and the third anti-reflection layer 530 are respectively installed on the first light incident surface 210, the second light incident surface 220, and the third light incident surface 230.

[0024] In this embodiment, the projection device 10 further includes a fourth anti-reflection layer 540, and among them, the fourth anti-reflection layer 540 is installed on the light exit surface 240. Since the first anti-reflection layer 510, the second anti-reflection layer 520, the third anti-reflection layer 530, and the fourth anti-reflection layer 540 are installed on the projection device 10, the light exit efficiency of the projection device 10 in the embodiment of the present invention can be effectively improved.

[0025] FIG. 2 is a diagram showing stray light of a projection screen after a third angle selector is installed in a projection device according to an embodiment of the present invention. In FIG. 2, the left diagram shows the stray light formed at the light exit surface of the light mixing module 200, and the right diagram shows the stray light formed after the light exits from the projection lens 400. As shown in FIG. 2, in the effective projection screen, the stray light is reduced by 66%, and the stray light outside the effective projection screen is only about 55%.

[0026] Accordingly, in one embodiment of the present invention, a first angle selector 310 is provided between the first display 110 and the light mixing module 200, a second angle selector 320 is provided between the second display 120 and the light mixing module 200, and a third angle selector 330 is provided between the third display 130 and the light mixing module 200. Therefore, the large-angle video light that may cause total internal reflection within the light mixing module 200 is reflected by the first angle selector 310, the second angle selector 320, and the third angle selector 330 and does not enter the light mixing module 200. When the incident angle of the video light beam incident on the light mixing module 200 is effectively limited, stray light of the projection device 10 can be reduced, and the contrast of the projection screen can be improved.

[0027] FIG. 3 is a diagram showing a projection device according to another embodiment of the present invention. As shown in FIG. 3, the projection device 10' in FIG. 3 is similar to the projection device 10 in FIG. 1. However, the main difference between the two is that in the projection device 10' in FIG. 3, the first angle selector 310, the second angle selector 320, and the third angle selector 330 are respectively (directly) installed on the first light incident surface 210, the second light incident surface 220, and the third light incident surface 230. Therefore, the overall volume of the projection device 10' can be reduced. Further, a fourth anti-reflection layer 540 is provided on the light exit surface 240 of the light mixing module 200 of the projection device 10'. Thereby, the light exit efficiency of the projection device 10' in the embodiment of the present invention can be effectively improved.

[0028] From the above, in one embodiment of the present invention, a first angle selector is provided between the first display and the light mixing module, a second angle selector is provided between the second display and the light mixing module, and a third angle selector is provided between the third display and the light mixing module. Therefore, stray light of the projection device can be effectively reduced, and the contrast of the projection screen can be made relatively high.

[0029] The present invention has been disclosed as above based on the foregoing preferred embodiments. However, the foregoing preferred embodiments are not intended to limit the present invention. Those skilled in the art can make minor changes and refinements to the present invention without departing from the technical idea and scope of the present invention. Therefore, the protection scope of the present invention is based on what is defined in the appended claims. Also, any embodiment or claim of the present invention does not have to achieve all the objects, advantages, or features disclosed in the present invention. Further, a part of the abstract and the name of the invention are only for assisting in the search of documents and do not limit the technical scope of the present invention. Also, terms such as "first" and "second" mentioned in this specification or claims are only for naming elements or distinguishing other embodiments or scopes, and are not for limiting the upper or lower limits in terms of the number of elements.

Explanation of Reference Numerals

[0030] 10, 10’: Projection device 110: First display 120: Second display 130: Third display 200: Light mixing module 210: First light incident surface 220: Second light incident surface 230: Third light incident surface 240: Light exit surface 310: First angle selector 320: Second angle selector 330: Third angle selector 400: Projection lens 510: First anti-reflection layer 520: Second anti-reflection layer 530: Third anti-reflection layer 540: Fourth anti-reflection layer B: Third video light beam G: Second video light beam R: First video light beam

Claims

1. A projection device including a first display, a second display, a third display, an optical mixing module, a first angle selector, a second angle selector, a third angle selector, and a projection lens, wherein the first display, the second display, and the third display are respectively used to provide a first video light beam, a second video light beam, and a third video light beam, the optical mixing module has a first light incident surface, a second light incident surface, a third light incident surface, and a light exit surface, the first angle selector is installed between the first display and the optical mixing module, the second angle selector is installed between the second display and the optical mixing module, and the third angle selector is installed between the third display and the optical mixing module, the projection lens is installed on the light exit surface side of the optical mixing module and is used to project the first video light beam, the second video light beam, and the third video light beam outside the projection device, the first video light beam, the second video light beam, and the third video light beam respectively pass through the first angle selector, the second angle selector, and the third angle selector and then propagate to the projection lens by the optical mixing module, a projection device.

2. The projection device according to claim 1, wherein the first light incident surface faces the third light incident surface, the second light incident surface faces the light exit surface, and the second light incident surface is connected to the first light incident surface and the third light incident surface, a projection device.

3. The projection device according to claim 1, wherein the first angle selector is a red light wavelength filter, the first angle selector allows the first video light beam with an incident angle smaller than 30 degrees to pass through and reflects the first video light beam with an incident angle of 30 degrees or more, a projection device.

4. The projection device according to claim 1, wherein the second angle selector is a green light wavelength filter, the second angle selector allows the second video light beam with an incident angle smaller than 30 degrees to pass through and reflects the second video light beam with an incident angle of 30 degrees or more, a projection device.

5. The projection device according to claim 1, wherein the third angle selector is a blue light wavelength filter, the third angle selector allows the third video light beam with an incident angle smaller than 30 degrees to pass through and reflects the third video light beam with an incident angle of 30 degrees or more, a projection device.

6. The projection device according to claim 1, further including a first anti-reflection layer, a second anti-reflection layer, and a third anti-reflection layer, The first antireflection layer, the second antireflection layer, and the third antireflection layer are respectively installed on the first light incident surface, the second light incident surface, and the third light incident surface, a projection device.

7. The projection device according to claim 1, The first angle selector, the second angle selector, and the third angle selector are respectively installed on the first light incident surface, the second light incident surface, and the third light incident surface, a projection device.

8. The projection device according to claim 1, The light mixing module reflects the first video light beam to the projection lens, transmits the second video light beam and propagates it to the projection lens, and reflects the third video light beam to the projection lens, a projection device.

9. The projection device according to claim 1, further comprising a fourth antireflection layer, The fourth antireflection layer is installed on the light exit surface of the light mixing module, a projection device.

10. The projection device according to claim 1, The light mixing module is a light mixing prism, a projection device.

11. The projection device according to claim 1, The first display, the second display, and the third display are micro light emitting diode display panels, a projection device.

Images