CN110677633A

CN110677633A - DLP projector capable of eliminating color deviation

Info

Publication number: CN110677633A
Application number: CN201910969860.9A
Authority: CN
Inventors: 饶钦和; 李衡; 岳德举; 白金刚
Original assignee: Guangdong Union University Optoelectronics Co Ltd
Current assignee: Guangdong Union University Optoelectronics Co Ltd
Priority date: 2019-10-12
Filing date: 2019-10-12
Publication date: 2020-01-10

Abstract

The present invention relates to a DLP projector, comprising: an illumination system serving as a light source; the dichroic mirror group is used for separating light emitted by the light source into first color light, second color light and third color light; three DLP light modulation devices for receiving images to be presented by the first to third color lights and modulating the first to third color lights into first to third signal lights; the light combiner is used for mixing the first signal light, the second signal light, the third signal light and the fourth signal light to obtain projection light; a projection lens for projecting the projection light onto an external screen; and three cooling devices thermally connected to the three DLP light modulation devices, respectively. The technical scheme of the invention can eliminate color deviation.

Description

DLP projector capable of eliminating color deviation

Technical Field

The invention relates to the technical field of projection, in particular to a DLP projector capable of eliminating color deviation.

Background

A projector, also called a projector, is a device that can project images or video onto a screen. With the advancement and breakthrough of technology, the mainstream projectors in the market have been occupied by conventional CRT three-gun type projectors, and gradually by DLP (digital light Processor) projectors. Compared with the traditional CRT projector, the DLP projector has the advantages of bright color, rich levels, high saturation and the like, is widely popular with consumers, and is widely applied to scenes such as life entertainment, academic lectures, business exhibition and the like.

In some application scenarios, such as the status and information of the transportation industry, the large screen of the game image is facing upward, and the need for correct color display is high. With the increase of the projection screen, and because human eyes are very sensitive to chromatic aberration, the phenomenon of color deviation of the DLP projector on the screen is easily perceived. Therefore, there is a need for an improvement of the existing DLP projector to eliminate the color shift phenomenon.

Disclosure of Invention

In view of the above, it is desirable to provide a DLP projector capable of eliminating the color shift phenomenon of a large screen display.

One aspect provides a DLP projector comprising:

an illumination system serving as a light source;

the dichroic mirror group is used for separating light emitted by the light source into first color light, second color light and third color light;

three DLP light modulation devices for receiving images to be presented by the first to third color lights and modulating the first to third color lights into first to third signal lights;

the light combiner is used for mixing the first signal light, the second signal light, the third signal light and the fourth signal light to obtain projection light;

a projection lens for projecting the projection light onto an external screen; and

three cooling devices thermally connected to the three DLP light modulation devices, respectively.

Each cooling device connected with the DLP light modulation device is far away from the light path of the DLP light modulation device.

The cooling device is an active cooling device.

The sizes of the images to be presented by the first to third color lights on the respective received DLP light modulation devices differ by no more than 3%, and the optical paths of the first to third color lights from the dichroic mirror to the respective DLP light modulation devices are on the same plane.

The light source of the illumination system is a white light source or a multi-wavelength light source.

The DLP projector has a lens or a reflecting mirror on a light path between the illumination system and the dichroic mirror or between the dichroic mirror and the DLP light modulation device.

The transmittance of each dichroic mirror is 50%, but the wavelengths of light that each dichroic mirror can transmit are different.

The DLP projector further includes a color filter.

Another aspect provides a DLP projection system comprising a DLP projector and a screen; the DLP projector is the DLP projector.

The DLP projector may have an optical axis of a projection lens connected to the center of the screen.

The DLP projector provided by the embodiment of the invention comprises a lighting system, a dichroic mirror, a DLP light modulator, a light combiner, a projection lens and a cooling device, wherein the cooling device can cool the DLP light modulator in a large-screen application scene, and avoids dust or other impurities from influencing a DMD (digital micromirror device) micromirror in the DLP light modulator due to thermal expansion, so that color deviation is eliminated.

Drawings

Fig. 1 is a schematic structural diagram of a DLP projection system according to an embodiment of the present invention;

fig. 2 is a schematic optical path diagram of a DLP projector according to an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention belong to the protection scope of the present invention.

Referring to fig. 1, a DLP projection system is provided in an embodiment of the present invention. The DLP projection system includes a DLP projector 1 and a screen 2. The application scene of the DLP projection system can be a large-scale game competition display platform or other commercial or entertainment industry information display platforms, the screen is large, and the color deviation phenomenon is easy to occur when the working power of the system is high. The existing DLP projector has stronger distortion sense when the viewer watches the image color along with the enlargement of the screen.

Specifically, referring to the embodiment of fig. 1, the DLP projector includes:

an illumination system serving as a light source;

The DLP projector of the embodiment of the invention is provided with the independent cooling devices in heat conduction connection for the DLP light modulation device working at high power, preferably an active cooling device, is connected with the light modulator through the easy heat conducting sheet such as the copper foil and the like, cools the light modulator, and prevents impurities in the air from entering the DLP light modulation device of each color separation, thereby influencing the DMD micro-mirror representing each pixel and further causing color deviation.

In this embodiment, the cooling device should be located away from the optical path for each color separation.

Further, the light path of the DLP projector of the present invention may be modified to eliminate color shift. The improvement of the optical path can comprise: the sizes of the images to be presented by the first to third color lights on the respective received DLP light modulation devices differ by no more than 3%, and the optical paths of the first to third color lights from the dichroic mirror to the respective DLP light modulation devices are on the same plane.

The working principle of the DLP projector according to the embodiment of the present invention will be described in detail with reference to the schematic optical path diagram shown in fig. 2.

The optical path of fig. 2 is a schematic optical path of the example of fig. 1 of the present invention, and only includes the optical devices necessary for explaining the present invention. In the optical path, other portions that can realize light integration, light guide, optical communication are not within the limitation of the present embodiment.

In the embodiment of fig. 2, the illumination system 52 in the DLP projector may be a single light source, or may have multiple light sources, and may be a single light source or a combination of light sources that produce white light, or a multi-wavelength light source that approximates white light. Illumination system 52 may also include an elliptical or parabolic reflector that emits multiple wavelengths of light toward a set of dichroic mirrors.

The set of dichroic mirrors in the embodiment of fig. 2 are two dichroic mirrors, each having a 50% transmission, each dichroic mirror transmitting (or reflecting) a different range of light wavelengths. The white light or multi-wavelength light emitted from the illumination system 52 is split into light rays in 3 wavelength ranges or three colors, i.e., first, second, and third color lights, by passing through the dichroic mirror twice. Preferably, the first, second and third color lights may correspond to three primary colors, i.e., red-band light, green-band light and blue-band light in the drawing, respectively.

The first through third colors of light (specifically, the three primary colors of light in fig. 2) are to be rendered in virtually every color component (e.g., R, G, B) of the overall image. The image of each color light is fed to a DLP light modulation device, which modulates it. The DLP light modulation device includes a plurality of DMD cells (each digital micromirror may correspond to a pixel), each pixel being independently addressable and drivable to convert first through third color lights into first through third signal lights. In the optical path diagram of fig. 2, 3 DLP light modulating devices (i.e., a red light modulator, a green light modulator, and a blue light modulator) are schematically depicted at 56a, 56b, and 56 c. As mentioned above, the optical path of the embodiment of the present invention may further include other integration devices, and only the components related to the present invention are described herein. In order to improve the color uniformity of the image, the size of the image to be rendered by each color light may be adjusted so that the size difference between them is not more than 3%, preferably not more than 0.5%. In some existing DLP projectors, the DLP light modulation device is configured to be three-dimensional, which also affects the uniformity of light color, and the light paths from the dichroic mirror to the DLP light modulation device of the respective color lights are arranged in the same plane, so that color shift can be effectively reduced, that is, the

light path portions

76a, 76b, and 76c in fig. 2 are in the same plane.

In fig. 2, 70 is a light combiner for combining the images representing the color components into a complete image, and 72 is a projection lens for magnifying the image onto an external screen. The optical axis of the projection lens may be at the center of the screen.

Further, referring to FIG. 2, to direct the sub-beams onto the light modulation device, additional optical components are used, which may be lenses and/or mirrors (e.g., 54). The lenses are typically made of optical glass with standard anti-reflective coatings on both sides. The lens may also be made of other materials, such as quartz, but optical glass is preferred because it is cheaper. The mirrors are typically made of float glass and have a standard reflective coating on one side. Color filters (specifically placed between the light modulators and the light combiner, not shown in fig. 2) may also be added in this embodiment, sometimes, for example, to further separate colors.

In the embodiment of fig. 2, 3 cooling devices may be provided in connection with each light modulation device to perform cooling processing for each color light modulation device. In a preferred embodiment, each cooling device comprises a closed enclosure wall, here exemplified as the first cooling device, the first cooling device may comprise a closed enclosure wall that encloses at least the red light modulation device, by sealing is meant that the enclosure wall prevents the passage of internal air from external air, and does not necessarily mean that the internal and external air pressures differ. And the closed wall does not influence the normal work of the light path. Or in another mode, the enclosure wall of the first cooling device seals both the first dichroic mirror and the red light modulator. The first cooling device has a heat path on the closed wall thereof, which is thermally conductive and can transmit heat of the red light modulator to the outside. And preferably, the first cooling device may be an active cooling device. The second and third cooling devices have the same principle as the first cooling device, except that the objects to be operated are a green light modulation device and a blue light modulation device, respectively. And the principle will not be described in detail.

In summary, the DLP projector provided in the embodiment of the present invention includes an illumination system, a dichroic mirror, a DLP optical modulator, a light combiner, a projection lens, and a cooling device, where the cooling device can cool the DLP optical modulator in a large screen application scene, so as to avoid dust or other impurities from affecting DMD micromirrors in the DLP optical modulator due to thermal expansion, thereby eliminating color deviation. In addition, the DLP projector according to the embodiment of the present invention improves the light path itself to eliminate color deviation.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A DLP projector, comprising:

an illumination system serving as a light source;

2. The DLP projector as claimed in claim 1 wherein each cooling means associated with a DLP light modulating means is located remotely from the path of light in which the DLP light modulating means is located.

3. The DLP projector as claimed in claim 2 wherein said cooling means is an active cooling means.

4. The DLP projector as claimed in claim 2 or 3 wherein the first through third color lights are to be rendered in images differing by no more than 3% in size on each respective received DLP light modulating device, and the optical paths of the first through third color lights from the dichroic mirror to each DLP light modulating device are in the same plane.

5. The DLP projector as claimed in claim 4 wherein the light source of the illumination system is a white light source or a multi-wavelength light source.

6. The DLP projector as claimed in claim 5 having a lens or mirror in the light path between the illumination system and the dichroic mirror or between the dichroic mirror and the DLP light modulation device.

7. The DLP projector as claimed in claim 1 wherein each said dichroic mirror has a 50% transmission, but each dichroic mirror transmits a different wavelength of light.

8. The DLP projector of claim 2 further comprising a color filter.

9. A DLP projection system, comprising a DLP projector and a screen; the DLP projector of claim 1.

10. The DLP projection system according to claim 8, wherein the optical axis of a projection lens in said DLP projector is connectable to the center of said screen.