CN218413186U - Projection system - Google Patents

Abstract

The application provides a projection system, comprising an illumination assembly, a light splitting assembly and a modulation assembly, wherein the illumination assembly is used for providing white light; the light splitting assembly is arranged on an emergent light path of the lighting assembly and is used for splitting the white light into first color light, second color light and third color light; the modulation component comprises a first spatial light modulator, a second spatial light modulator, a third spatial light modulator and a pre-modulation spatial light modulator; the light splitting component is also used for guiding the first color light to the first spatial light modulator, guiding the second color light to the second spatial light modulator and guiding the third color light to the pre-modulation spatial light modulator for pre-modulation; the light path of the first color light and the light path of the second color light are conjugated; the premodulation spatial light modulator is used for premodulating the third chromatic light according to the facula homogeneity of first chromatic light or second chromatic light for the facula homogeneity of first chromatic light, second chromatic light and third chromatic light is unanimous, and then makes the display brightness of projecting image more even, avoids appearing "colored face" phenomenon.

Description

Projection system

Technical Field

The application relates to the technical field of optical systems, in particular to a projection system.

Background

The 3DLP (Digital Light Processing) projection system is a common projection system, and the basic principle of the 3DLP projection system is to separate white Light emitted by an illumination Light source into red, green and blue Light beams through a dichroic mirror, and the Light beams are respectively incident on three corresponding Light valves, and the Light valves modulate incident Light beams according to input image signals, and then combine Light beams emitted by the three Light valves into a combined Light beam through a Light combining prism, and the combined Light beam can form a projection image on a screen after being projected to the screen through a projection lens. However, in the existing 3DLP projection system, the uniformity of light spots of the red, green and blue light before modulation is different, which eventually causes the display brightness of the projected image to be uneven, and the phenomenon of "faceting" occurs, which affects the projection effect.

SUMMERY OF THE UTILITY MODEL

The present application is directed to a projection system to solve the above problems. The application achieves the above object by the following technical scheme.

The embodiment of the application provides a projection system, which comprises an illumination assembly, a light splitting assembly and a modulation assembly, wherein the illumination assembly is used for providing white light; the light splitting assembly is arranged on an emergent light path of the lighting assembly and is used for splitting the white light into first color light, second color light and third color light; the modulating component comprises a first spatial light modulator, a second spatial light modulator, a third spatial light modulator and a premodulating spatial light modulator, and the premodulating spatial light modulator is arranged on a light path between the light splitting component and the third spatial light modulator; the light splitting component is also used for guiding the first color light to the first spatial light modulator for modulation, guiding the second color light to the second spatial light modulator for modulation, and guiding the third color light to the pre-modulation spatial light modulator for pre-modulation; the light path of the first color light and the light path of the second color light are conjugated; the pre-modulation spatial light modulator is used for pre-modulating the spot uniformity of the third color light according to the spot uniformity of the first color light or the second color light and then transmitting the third color light to the third spatial light modulator.

The projection system that this application embodiment provided is through the light path conjugation that sets up the light path of first chromatic light and second chromatic light, it is the same to guarantee the facula homogeneity of first chromatic light and second chromatic light, the facula homogeneity of third chromatic light is carried out the premodulation according to the facula homogeneity of first chromatic light or second chromatic light to the spatial light modulator of rethread, make the facula homogeneity of first chromatic light, second chromatic light and third chromatic light unanimous, and then make the display luminance of projected image more even, avoid appearing "face of flower" phenomenon.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a projection system provided in an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a light combining prism and a spatial light modulator in a projection system according to an embodiment of the present disclosure.

Fig. 3 is a block diagram of a projection system provided in an embodiment of the present application.

Fig. 4 is a schematic structural diagram of a projection system according to another embodiment of the present application.

Fig. 5 is a schematic structural diagram of a polarization shaper in the projection system provided in the embodiment shown in fig. 4.

Fig. 6 is a schematic structural diagram of a projection system according to yet another embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative and are only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In the existing 3DLP projection system, the light spot uniformity of red, green and blue light before modulation is different, which finally causes the uneven display brightness of the projected image, and the phenomenon of 'face-up' appears, thus affecting the projection effect.

In order to solve the above technical problems, the inventors have found through research that: the uniformity of the light spots of the red light, the green light and the blue light before modulation is different because of different light paths, unequal light paths and the like of the red light, the green light and the blue light. In view of this, the inventor provides a projection system, by setting the light path of the first color light and the light path of the second color light to be conjugate, it is ensured that the uniformity of light spots of the first color light and the second color light is the same, and then the light spot uniformity of the third color light is pre-modulated by the pre-modulation spatial light modulator according to the light spot uniformity of the first color light or the second color light and then enters the third spatial light modulator, so that the uniformity of light spots of the first color light, the second color light and the third color light before modulation is consistent, further, the brightness of a projected image is more uniform, and the phenomenon of 'faceting' is avoided.

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be apparent that the described embodiments are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, a projection system 100 provided in the embodiment of the present application includes an illumination assembly 110, a light splitting assembly 130 and a modulation assembly 150, where the illumination assembly 110 is configured to provide white light, and the light splitting assembly 130 is disposed on an exit light path of the illumination assembly 110 and is configured to split the white light into a first color light 111, a second color light 112 and a third color light 113. The modulation assembly 150 includes a first spatial light modulator 151, a second spatial light modulator 152, a third spatial light modulator 153, and a pre-modulation spatial light modulator 154, the pre-modulation spatial light modulator 154 is disposed on the optical path between the light splitting assembly 130 and the third spatial light modulator 153; the light splitting assembly 130 is further configured to direct the first color light 111 to the first spatial light modulator 151 for modulation, direct the second color light 112 to the second spatial light modulator 152 for modulation, and direct the third color light 113 to the pre-modulation spatial light modulator 154 for pre-modulation.

The optical path of the first color light 111 and the optical path of the second color light 112 are conjugate, and the pre-modulation spatial light modulator 154 is configured to pre-modulate the spot uniformity of the third color light 113 according to the spot uniformity of the first color light 111 or the second color light 112 and then enter the third spatial light modulator 153. The optical path of the first color light 111 refers to the optical path from the light splitting component 130 to the first spatial light modulator 151 of the first color light 111, and the optical path of the second color light 112 refers to the optical path from the light splitting component 130 to the second spatial light modulator 152 of the second color light 112.

The projection system 100 provided in the embodiment of the present application sets the light path of the first color light 111 and the light path of the second color light 112 to be conjugate, that is, the light path of the first color light 111 and the light path of the second color light 112 are arranged along the light splitting assembly 130 in a mirror image manner, and the light path of the first color light 111 is equal to the light path of the second color light 112, so that it is ensured that the uniformity of the light spots of the first color light 111 and the second color light 112 is the same, and then the light spot uniformity of the third color light 113 is pre-modulated by the pre-modulation spatial light modulator 154 according to the light spot uniformity of the first color light 111 or the second color light 112, so that the uniformity of the light spots of the first color light 111, the second color light 112, and the third color light 113 is the same, further, the brightness of a projected image is more uniform, and a 'face-up' phenomenon is avoided. In addition, the pre-modulation spatial light modulator 154 may also perform Local Dimming (Local Dimming), that is, the light spot emitted by the pre-modulation spatial light modulator 154 is modulated according to the brightness of each pixel corresponding to the first color light 111 or the second color light 112, so as to improve the light emitting efficiency of the system and reduce the thermal load of the pre-modulation spatial light modulator 154.

In this embodiment, the projection system 100 further includes a light combining prism 161 and a projection lens 162, where the light combining prism 161 is disposed between the first spatial light modulator 151, the second spatial light modulator 152 and the third spatial light modulator 153, and is configured to combine light beams emitted by the first spatial light modulator 151, the second spatial light modulator 152 and the third spatial light modulator 153 into a combined light beam. The projection lens 162 is disposed on the light-emitting path of the light-combining prism 161, and is used for projecting the combined light emitted from the light-combining prism 161 onto a screen to form a projection image.

The light combining prism 161 may be a cross dichroic color combining prism (abbreviated as "X-cube"), the projection lens 162 may be a lens group composed of a plurality of lenses, and an aperture stop of the projection lens 162 may be disposed outside the projection lens 162, for example, at the foremost of the entire lens group, or at the rearmost of the entire lens group, which enables miniaturization and cost reduction of the projection lens 162.

In some embodiments, the projection system 100 may further include a pixel shifting device 163, where the pixel shifting device 163 is disposed on an optical path between the light combining prism 161 and the projection lens 162, and is configured to translate the combined light emitted by the light combining prism 161 along a direction perpendicular to an optical axis of the projection lens 162, and superimpose the combined light at different translation positions in a time sequence, so as to implement a small displacement of an image, and further implement an improvement of the display resolution.

In some embodiments, the pixel shifting device 163 may be a transparent flat optical device using XPR (pixel shift resolution system) technology, and the transparent flat optical device may control the rotation angle by current or voltage. Specifically, when the transparent plate of the pixel shift device 163 is rotated by a certain angle, light passing through the transparent plate is refracted twice and then translated as a whole, the transparent plate stays at the rotated position for a predetermined time, and then is rotated to other positions. In one image frame period, the pixel shifting device 163 may include 2 or 4 stable states, the image is divided into 2 or 4 sub-frames, and the human eye superimposes the captured 2 or 4 images through a time integration function, thereby forming a high resolution image in the brain. It will be appreciated that the pixel shifting means 163 may also include more stable states to achieve higher resolution, and the present invention is not limited by the number of pixel multiplications.

In some embodiments, the pixel shift device 163 may also be a liquid crystal birefringence device adopting an E-shift (pixel expansion) technology, and the deflection angle of liquid crystal molecules is controlled by voltage, so as to translate light passing through the liquid crystal birefringence device, thereby implementing an effect of shifting the whole pixel, and the effect is similar to that of the pixel shift device 163 with mechanical rotation, and is not described herein again.

When the pixel shifting device 163 uses the XPR technique, there is no requirement on the polarization state of incident light. When the pixel shift device 163 adopts the E-shift technology, the light entering the pixel shift device 163 is required to be light of the same polarization state. In the projection system 100, in order to maximize efficiency, green light generally passes through the light combining prism 161 in P-polarization state, and red light and blue light generally pass through the light combining prism 161 in S-polarization state, which utilizes that the width of the P-polarized high reflection region is always smaller than that of S-polarization when incident obliquely, so that the transmission region of P-polarized light in RDM (anti-red film) and BDM (anti-blue film) of the light combining prism 161 can be made very wide, thereby realizing almost lossless spectrum passing through the light combining prism 161.

When the pixel shift device 163 adopts the E-shift technology, there are two methods to make the light entering the pixel shift device 163 be the light in the same polarization state, wherein one method is to cut the spectrum, specifically, a color filter may be added to each of the light paths of the first color light 111, the second color light 112, and the third color light 113 by cutting the spectrum, for example, a color filter is respectively disposed on the light path between the first spatial light modulator 151 and the light combining prism 161, the light path between the second spatial light modulator 152 and the light combining prism 161, and the light path between the third spatial light modulator 153 and the light combining prism 161; alternatively, the light combining prism 161 has a filtering function, and thus can be realized by filtering light by the light combining prism 161. Alternatively, a COLOR separator may be added to the optical path between the light combining prism 161 and the pixel shifting device 163 for converting the polarization of light with a specific wavelength, such as red and blue light into P-polarization or green light into S-polarization, so that all incident light is incident on the pixel shifting device 163 with the same polarization.

In some embodiments, the first spatial light modulator 151, the second spatial light modulator 152, the third spatial light modulator 153, and the pre-modulation spatial light modulator 154 are all LTPS (Low Temperature polysilicon) liquid crystal light valves. The LTPS liquid crystal light valve is also a transmission type spatial light modulator manufactured by adopting an LTPS process, realizes the modulation of light beams by changing the orientation of liquid crystals and combining a polarizer and an analyzer, has low cost and is suitable for large-scale production and application.

In this embodiment, the projection system 100 further includes a first polarizer 171, a second polarizer 172, and a third polarizer 173, the first polarizer 171 is disposed on the optical path between the light splitting assembly 130 and the first spatial light modulator 151, and the first color light 111 is polarized by the first polarizer 171 and then enters the first spatial light modulator 151 in a single polarization state for modulation. The second polarizer 172 is disposed on the optical path between the light splitting assembly 130 and the second spatial light modulator 152, and the second color light 112 is polarized by the second polarizer 172 and then enters the second spatial light modulator 152 in a single polarization state for modulation. The third polarizer 173 is disposed on the optical path between the pre-modulation spatial light modulator 154 and the third spatial light modulator 153, and the third color light 113 is polarized by the third polarizer 173 and then enters the third spatial light modulator 153 in a single polarization state for modulation.

The projection system 100 may further include a first analyzer (not shown), a second analyzer (not shown), and a third analyzer (not shown), where the first analyzer is disposed on an optical path between the first spatial light modulator 151 and the light combining prism 161, and the first analyzer and the first spatial light modulator 151 may be bonded together or disposed separately from each other, and are configured to perform polarization purification on image light emitted from the first spatial light modulator 151, and filter out a light beam meeting a polarization state requirement in the modulated light to the light combining prism 161. The second analyzer is disposed on the light path between the second spatial light modulator 152 and the light combining prism 161, and the second analyzer and the second spatial light modulator 152 may be bonded together or disposed separately from each other, so as to perform polarization purification on the modulated light emitted from the second spatial light modulator 152, and filter out the light beam meeting the polarization state requirement in the modulated light to the light combining prism 161. The third analyzer is disposed on the light path between the third spatial light modulator 153 and the light combining prism 161, and the third analyzer and the third spatial light modulator 153 may be bonded together or disposed separately from each other, so as to perform polarization purification on the modulated light emitted from the third spatial light modulator 153, and filter out the light beam meeting the polarization state requirement in the modulated light to the light combining prism 161.

Referring to fig. 1 and fig. 2, in the present embodiment, the first spatial light modulator 151, the second spatial light modulator 152, and the third spatial light modulator 153 are all LTPS liquid crystal light valves, and the first spatial light modulator 151, the second spatial light modulator 152, and the third spatial light modulator 153 are all substantially rectangular plate-shaped structures and have a length direction and a width direction. The first spatial light modulator 151 and the third spatial light modulator 153 may be disposed opposite to each other on both sides of the second spatial light modulator 152 in the width direction, and the first spatial light modulator 151, the second spatial light modulator 152, and the third spatial light modulator 153 may be aligned in the length direction.

The length of the light combining prism 161 in the light outgoing direction of the second spatial light modulator 152 is adapted to the widths of the first spatial light modulator 151 and the third spatial light modulator 153, for example, the length of the light combining prism 161 in the light outgoing direction of the second spatial light modulator 152 is equal to the widths of the first spatial light modulator 151 and the third spatial light modulator 153, or the length of the light combining prism 161 in the light outgoing direction of the second spatial light modulator 152 is slightly smaller than or slightly larger than the widths of the first spatial light modulator 151 and the third spatial light modulator 153. Wherein the light emitting direction of the second spatial light modulator 152 is perpendicular to the second spatial light modulator 152.

Therefore, the length of the light combining prism 161 in the light outgoing direction of the second spatial light modulator 152 only needs to be matched with the widths of the first spatial light modulator 151 and the third spatial light modulator 153, but does not need to be matched with the lengths of the first spatial light modulator 151 and the third spatial light modulator 153, so that the length of the light combining prism 161 in the light outgoing direction of the second spatial light modulator 152 and the back intercept of the projection lens 162 can be reduced, and the whole projection system 100 is more compact.

It is understood that, in other embodiments, the first spatial light modulator 151, the second spatial light modulator 152, the third spatial light modulator 153 and the pre-modulation spatial light modulator 154 may also be a reflective Digital Micromirror Device (DMD) or a reflective LCOS (Liquid Crystal on Silicon) Device based on MEMS (Micro-Electro-Mechanical System) technology, etc.

In some embodiments, the pre-modulation spatial light modulator 154 may have a smaller resolution than the third spatial light modulator 153, while the first, second and third spatial light modulators 151, 152, 153 have the same resolution. For example, the resolution of the third spatial light modulator 153 is 1920 × 1152 pixels, and the resolution of the pre-modulation spatial light modulator 154 is 1280 × 768 pixels, so that not only can the requirement of the pre-modulation pixels be met, but also the transmittance can be mentioned, and the heat load of the pre-modulation spatial light modulator 154 can be reduced. It will be appreciated that in other embodiments, the resolution of the pre-modulation spatial light modulator 154 may be equal to the third spatial light modulator 153.

Referring to fig. 1 and fig. 3, in some embodiments, the projection system 100 may further include a detection unit 164 and a control unit 165, where the detection unit 164 is configured to detect the spot uniformity of the first color light 111 or the second color light 112 and generate detection data; the control unit 165 is electrically connected to the detection unit 164 and the pre-modulation spatial light modulator 154, and is configured to obtain a pre-modulation signal according to the detection data and send the pre-modulation signal to the pre-modulation spatial light modulator 154, where the pre-modulation spatial light modulator 154 is configured to pre-modulate the third color light 113 according to the pre-modulation signal. Therefore, the whole pre-modulation process of the third color light 113 can be automatically carried out without manual operation, and the pre-modulation signal can be output in real time according to the light spot uniformity of the first color light 111 or the second color light 112, so that the pre-modulation process is more accurate.

In this embodiment, the detection unit 164 may be a CCD (charge coupled device) camera, and the control unit 165 calculates the uniformity of the light spots by analyzing an image captured by the CCD camera, and obtains the pre-modulation signal according to the calculation of the uniformity of the light spots.

Still referring to fig. 1, in some embodiments, the light splitting assembly 130 may include a first light splitting prism 131, a first light guiding member 132, a second light guiding member 133 and a second light splitting prism 134, the first light splitting prism 131 is disposed on an emergent light path of the illumination assembly 110 and is used for splitting the white light into the first color light 111 and the fourth color light 114, and the first light guiding member 132 is disposed on the emergent light path of the first color light 111 and is used for guiding the first color light 111 to the first spatial light modulator 151; the second light guide 133 and the second dichroic prism 134 are sequentially disposed on the exit light path of the fourth color light 114, the fourth color light 114 enters the second dichroic prism 134 through the second light guide 133 and is split into the second color light 112 and the third color light 113, the second color light 112 enters the second spatial light modulator 152, and the third color light 113 enters the pre-modulation spatial light modulator 154. Thus, the light splitting assembly 130 can split the white light into the first color light 111, the second color light 112 and the third color light 113, guide the first color light 111 to the first spatial light modulator 151 for modulation, guide the second color light 112 to the second spatial light modulator 152 for modulation, and guide the third color light 113 to the pre-modulation spatial light modulator 154 for pre-modulation.

The light path of the second color light 112 is formed by splitting the fourth color light 114, and the light path through which the fourth color light 114 passes is equivalent to the light path through which the second color light 112 passes, so that the light path of the fourth color light 114 partially overlaps with the light path of the second color light 112, that is, the light path between the fourth color light 114 and the light path from the spectroscopic surface of the first dichroic prism 131 to the spectroscopic surface of the second dichroic prism 134 of the second color light 112 overlaps with each other, and the light path of the first color light 111 and the light path of the second color light 112 in the above embodiment are conjugated, that is, the light path of the first color light 111 is conjugated with the total light path of the fourth color light 114 and the total light path of the second color light 112.

In this embodiment, the first light splitting prism 131 includes a first light splitting surface 1311, and a first color light emitting surface (not numbered) and a fourth color light emitting surface (not numbered) that are mirror images of each other with respect to the first light splitting surface 1311, the white light emitted from the illumination assembly 110 enters the first light splitting surface 1311, and is split into a first color light 111 and a fourth color light 114 on the first light splitting surface 1311, the first color light 111 exits through the first color light emitting surface, and the fourth color light 114 exits through the fourth color light emitting surface.

The first light guiding member 132 includes a first light guiding pipe 1321 and a light path turning member 1322, the first light guiding pipe 1321 is connected between the first color light emitting surface and the light path turning member 1322 for guiding the first color light 111 to the light path turning member 1322, and the light path turning member 1322 is for guiding the first color light 111 to the first spatial light modulator 151; the second light guiding member 133 includes a second light guiding pipe 1331, and the second light guiding pipe 1331 is connected between the fourth color light emitting surface and the second light splitting prism 134, and is used for guiding the fourth color light 114 to the second light splitting prism 134.

The second dichroic prism 134 includes a second dichroic surface (not numbered in the figure), and a second color light emitting surface and a third color light emitting surface which are mirror images with respect to the second dichroic surface, the fourth color light 114 enters the second dichroic surface and is split into the second color light 112 and the third color light 113 at the second dichroic surface, the second color light 112 is emitted through the second color light emitting surface, and the third color light 113 is emitted through the third color light emitting surface.

The first light pipe 1321 and the second light pipe 1331 are mirror images of each other with respect to the first light splitting surface 1311, and the light emitting surface of the second color light and the light emitting surface of the light path turning member 1322 are mirror images of each other with respect to the first light splitting surface 1311, so that the light path of the first color light 111 in the light splitting assembly 130 is conjugate to the total light path of the fourth color light 114 and the second color light 112 in the light splitting assembly 130.

Further, the first spatial light modulator 151 and the second spatial light modulator 152 are mirror images of each other with respect to the first light splitting plane 1311, so that the optical path of the first color light 111 from the light splitting component 130 to the first spatial light modulator 151 and the total optical path of the fourth color light 114 and the second color light 112 from the light splitting component 130 to the second spatial light modulator 152 are conjugate.

In this embodiment, the first light splitting prism 131 and the second light splitting prism 134 may be dichroic light splitting prisms, the first light splitting surface 1311 is located in the first light splitting prism 131, an included angle of 45 ° is formed between the first light splitting surface 1311 and the optical axis of the lighting assembly 110, and both the first color light emitting surface and the fourth color light emitting surface form an included angle of 45 ° with the first light splitting surface 1311, that is, the first color light emitting surface and the fourth color light emitting surface are perpendicular to each other. The second light splitting surface is located in the second light splitting prism 134, the second light splitting surface is parallel to the first light splitting surface 1311, and the second color light emitting surface and the third color light emitting surface both form an included angle of 45 degrees with the second light splitting surface, that is, the second color light emitting surface and the third color light emitting surface are perpendicular to each other.

As an example, the first color light 111 is red light, the second color light 112 is green light, the third color light 113 is blue light, and the fourth color light 114 is yellow light. Specifically, the first light splitting surface 1311 is coated with a yellow-reflective and red-transmissive film, and the second light splitting surface is coated with a green-reflective and blue-transmissive film, so that white light emitted by the lighting assembly 110 is incident on the yellow-reflective and red-transmissive film and split into red light (the first color light 111) and yellow light (the fourth color light 114), and yellow light is incident on the green-reflective and blue-transmissive film and split into green light (the second color light 112) and blue light (the third color light 113).

In this embodiment, the first light pipe 1321 and the second light pipe 1331 may be both hollow pipes, the light path turning piece 1322 is a right-angle prism, one right-angle surface of the right-angle prism is connected to the first light pipe 1321 to serve as a light incident surface, the other right-angle surface of the right-angle prism faces the first spatial light modulator 151 to serve as a light emitting surface, and an inclined surface of the right-angle prism forms an included angle of 45 degrees with an optical axis of the first light pipe 1321, so as to deflect the first color light 111 by 90 degrees and then enter the first spatial light modulator 151. The shape of the exit surface of the first light guide 1321 may be matched with the shape of the entrance surface of the optical path bending piece 1322 and may overlap with each other, so that an optical waveguide can be formed, and the optical path can be bent while maintaining the etendue.

The light incident surface of the light path deflecting member 1322 may be plated with a first optical multilayer interference film, the light exit surface of the light path deflecting member 1322 may be plated with a second optical multilayer interference film, and both the first optical multilayer interference film and the second optical multilayer interference film are configured to transmit light rays having an incident angle smaller than a first angle value and conforming to a set wavelength range, and reflect light rays having an incident angle larger than a second angle value and conforming to the set wavelength range; the first angle value is smaller than the second angle value, that is, the first optical multilayer interference film and the second optical multilayer interference film can transmit small-angle incident light and reflect large-angle incident light for light with a specific spectrum width, so that the large-angle light reflected by the reflecting surface of the light path bending piece 1322 can be prevented from passing through the light incident surface of the light path bending piece 1322 again and returning to the first light guide 1321, thereby maximally preventing light waste caused by reverse transmission of light and improving the utilization rate of light energy.

The first light splitting prism 131 may include a first right-angle prism and a second right-angle prism, inclined surfaces of which are glued to each other to form a first light splitting surface 1311, the first and second right-angle prisms being mirror images of each other with respect to the first light splitting surface 1311. The second dichroic prism 134 may include a third right-angle prism and a fourth right-angle prism, inclined surfaces of the third right-angle prism and the fourth right-angle prism are glued to each other to form a second dichroic surface, the third right-angle prism is provided with a second color light emitting surface, and the fourth right-angle prism is provided with a third color light emitting surface. The third rectangular prism and the light path turning member 1322 are mirror images of each other with respect to the first light splitting surface 1311, so that the light-emitting surface of the second color light and the light-emitting surface of the light path turning member 1322 are mirror images of each other with respect to the first light splitting surface 1311.

In this embodiment, the projection system 100 may further include a first reflection member 181 and a second reflection member 182, the first reflection member 181 and the second reflection member 182 are sequentially disposed on a light path between the pre-modulation spatial light modulator 154 and the third spatial light modulator 153, and a light beam emitted from the pre-modulation spatial light modulator 154 is sequentially reflected by the first reflection member 181 and the second reflection member 182 and then enters the third spatial light modulator 153, so that the pre-modulated third color light 113 is guided to the third spatial light modulator 153.

The first reflector 181 and the second reflector 182 may be both planar reflectors, and a normal of a reflective surface of the first reflector 181 forms an included angle of 45 ° with an optical axis of the pre-modulation spatial light modulator 154, a normal of a reflective surface of the second reflector 182 forms an included angle of 45 ° with an optical axis of the third spatial light modulator 153, and a normal of a reflective surface of the first reflector 181 forms an included angle of 45 ° with a normal of a reflective surface of the second reflector 182, so that the third color light 113 can be reflected by 180 ° and then enter the third spatial light modulator 153 through cooperation of the first reflector 181 and the second reflector 182.

In some embodiments, the third color light is blue light, and the modulation assembly 150 further comprises a pre-imaging lens 155, the pre-imaging lens 155 being disposed in an optical path between the pre-modulated spatial light modulator 154 and the third spatial light modulator 153, such as in an optical path between the first reflective member 181 and the second reflective member 182, for pre-imaging the light beam emitted from the pre-modulated spatial light modulator 154.

In other embodiments, the third color light is not blue, for example, the third color light is green, and the third color light can be directly incident on the third spatial light modulator 153 after being pre-modulated by the pre-modulation spatial light modulator 154 without being pre-imaged by the pre-imaging lens 155.

In some embodiments, the projection system 100 may further include a first relay lens 183 and a second relay lens 184, the first relay lens 183 and the second relay lens 184 being sequentially disposed on the optical path between the pre-modulation spatial light modulator 154 and the third spatial light modulator 153, for example, the first relay lens 183 is disposed on the optical path between the pre-modulation spatial light modulator 154 and the first reflector 181, and the second relay lens 184 is disposed on the optical path between the second reflector 182 and the third spatial light modulator 153, so as to relay the pre-modulated third color light 113 to the third spatial light modulator 153.

In some embodiments, the projection system 100 may further include a first field lens, a second field lens, and a third field lens, which may be convex lenses or fresnel lenses, the first field lens being disposed on the optical path between the light splitting assembly 130 and the first spatial light modulator 151, for example, between the optical path deflecting member 1322 and the first polarizer 171, or between the first polarizer 171 and the first spatial light modulator 151, for converging the first color light 111 to the first spatial light modulator 151. The second field lens is disposed in the optical path between the beam splitting assembly 130 and the second spatial light modulator 152, for example, between the second beam splitting prism 134 and the second polarizer 172, or between the second polarizer 172 and the second spatial light modulator 152, for converging the second color light 112 to the second spatial light modulator 152. The third field lens is disposed on the optical path between the light splitting assembly 130 and the third spatial light modulator 153, for example, between the second relay lens 184 and the third polarizer 173, or between the third polarizer 173 and the third spatial light modulator 153, and is configured to converge the third color light 113 to the third spatial light modulator 153. The first field lens and the second field lens may be mirror images of each other with respect to the first light splitting plane 1311, so as to ensure that the light paths of the first color light 111 and the second color light 112 are conjugate.

The projection system 100 can converge telecentric light (parallel light) into convergent light (non-telecentric light) by using the converging effect of the first field lens, the second field lens and the third field lens on light, so that light with different fields of view on the spatial light modulator has different chief ray incident angles, and especially when the chief ray incident angles are in a converging state, the size of the light combining prism 161 is favorably reduced, the overall length of the projection lens 162 is shortened, the design difficulty of the projection lens 162 can be reduced, and the cost of the projection lens 162 is reduced.

In some embodiments, the illumination assembly 110 includes an illumination light source 115 and a collecting device 116, the illumination light source 115 is configured to emit white light, and the collecting device 116 is disposed on an emitting light path of the illumination light source 115 and configured to emit the white light to the light splitting assembly 130 after being collected into parallel light.

In this embodiment, the collecting device 116 may include a tapered dodging device 1161 and a lens 1162, the tapered dodging device 1161 and the lens 1162 are sequentially disposed on an emergent light path of the illumination light source 115, and a light beam emitted by the illumination light source 115 is collimated by the tapered dodging device 1161 and the lens 1162 to form parallel light. The tapered light uniformizing device 1161 may be a solid tapered light guiding rod or a hollow tapered reflector, and the lens 1162 may be a convex lens or a fresnel lens.

The tapered dodging device 1161 has an incident surface on a side facing the illumination source 115 and an exit surface on a side facing the lens, and the area of the incident surface is smaller than that of the exit surface. After light beams emitted by the illumination light source 115 enter the tapered dodging device 1161 through the incident surface, the light beams are reflected by the inner side wall of the tapered dodging device 1161 and then are emitted through the emergent surface, so that the area of emergent light spots is larger than that of incident light spots, and the divergence angle of the light beams is reduced.

In this embodiment, the illumination light source 115 may be an LED lamp (yellow phosphor is coated on a blue LED chip), a laser phosphor light source (yellow phosphor is excited by blue laser), or a mixed RGB three-color laser.

When the illumination light source 115 is an LED lamp or a laser fluorescent light source, the projection system 100 may further include an excitation light source, and the excitation light source is configured to emit excitation light to the illumination light source 115 to excite the illumination light source 115 to generate excitation light, so as to form double-sided excitation to the illumination light source 115 and improve the maximum output lumens of the illumination light source 115. For example, the illumination source 115 may be configured to generate white light by exciting the yellow phosphor with blue light, and the excitation source may be configured to emit blue light, and the blue light may be irradiated onto the yellow phosphor of the illumination source 115 to form a double-sided excitation of the yellow phosphor.

In some embodiments, the illumination source 115 is a surface light source, and can directly emit divergent light with a wide beam diameter, in this case, the collecting device 116 can be a discrete conical rod lens array or a discrete collecting lens array, for example, the collecting device 116 can include a plurality of micro lenses arranged in an array, and these micro lenses can correspond to the single sub-light sources or partitions of the surface light source one by one, so that discrete multi-area illumination can be formed, and the volume of the whole projection system 100 can be further reduced.

Referring to fig. 4, in some embodiments, the collecting device 116 may be a collecting lens 1163, and the light beam emitted from the illumination source 115 is shaped into parallel light by the collecting lens 1163. The collecting lens 1163 may be a plano-convex lens or a biconvex lens, and the number of the collecting lens 1163 may include one or more. For example, the number of the collecting lenses 1163 is two, and the two collecting lenses 1163 are sequentially disposed along the exit optical path of the illumination light source 115.

In some embodiments, the projection system 100 may further include a polarization device 174, and the polarization device 174 is disposed on the optical path between the illumination assembly 110 and the light splitting assembly 130, for example, between the collecting device 116 and the first light splitting prism 131, and is configured to polarize the white light emitted from the collecting device 116 to form white light with a single polarization state, and to be incident on the light splitting assembly 130, so that the fourth color light 114 can be incident on the pre-modulated spatial light modulator 154 with a single polarization state.

The polarizing device 174, the first polarizer 171, the second polarizer 172, and the third polarizer 173 are used for polarizing the light into the light with the same polarization state, which is equivalent to polarizing each color light at least twice, so that the polarization purity of the light can be improved, and the projection contrast ratio can be further improved. It will be appreciated that in other embodiments where the pre-modulated spatial light modulator 154 is a reflective digital micromirror device or a reflective LCOS device, the projection system 100 may be unbiased by the polarizing device 174.

Referring to fig. 4 and 5, in some embodiments, the polarization device 174 is a polarization shaper 175, and the polarization shaper 175 is used to shape the white light emitted from the collecting device 116 to form recycled light and image light having a predetermined spot shape and a single polarization state, where the image light is incident on the light splitting assembly 130, and the recycled light is reflected back to the collecting device 116 to improve the utilization rate of the light.

As an example, the shape of the light spot emitted by the collecting device 116 is circular, and the area to be illuminated by the first spatial light modulator 151 is rectangular, then the preset light spot shape of the image light is rectangular adapted to the first spatial light modulator 151, and then the rectangular light spot can be cut out from the circular light spot by the polarization device 174, so as to form the image light with the rectangular light spot to illuminate the first spatial light modulator 151, and the recycled light not participating in illumination is reflected back to the collecting device 116. When the collecting device 116 includes the tapered light uniformizing device 1161 (see fig. 1 in detail), the recycled light can be directly recycled and reused through the tapered light uniformizing device 1161; when the collecting device 116 is the collecting lens 1163, the recycled light can be transmitted through the collecting lens 1163 and returned to the illumination source 115, and the illumination source 115 can reflect the recycled light back to the collecting lens 1163 to continue to participate in the light circulation.

The polarization shaper 175 may be a polarization shaping film, the polarization shaper 175 is provided with a first region 1751 and a second region 1752, the first region 1751 is arranged around the outer circumference of the second region 1752, and the shape of the second region 1752 is adapted to the illumination region of the first spatial light modulator 151, for example, when the illumination region of the first spatial light modulator 151 is rectangular, the first region 1751 is rectangular. The first region 1751 may be coated with a reflective film, the second region 1752 may be coated with a polarizing film, and when the light beam emitted from the collecting device 116 passes through the polarization shaper 175, a portion of the light passes through the polarizing film of the second region 1752 to form image light having a single polarization state and a predetermined spot shape, and the other portion is reflected by the reflective film of the first region 1751 to form recycled light.

Further, the polarizing film plated in the second region 1752 may be a reflective polarizing film, such as a reflective polarizing brightness enhancement film (DBEF) or a metal wire grid, through which the polarization shaper 175 can be used to split the image light into a first polarized light and a second polarized light with a polarization state different from that of the first polarized light, where the first polarized light is incident to the light splitting assembly 130, and the second polarized light is reflected back to the collecting device 116, so that recycling of the second polarized light is realized, and system efficiency is further improved.

Taking the first spatial light modulator 151 as an example, the image light is split into P-polarized light and S-polarized light by the reflective polarizing film, where the P-polarized light is irradiated to the corresponding first spatial light modulator 151, the S-polarized light is reflected back to the collecting device 116 and can be returned to the illumination light source 115 through the collecting device 116, and when the illumination light source 115 is an LED lamp or laser fluorescence, the S-polarized light can be dispersed into natural light again and then continuously participate in light circulation.

Referring to fig. 6, in some embodiments, the light splitting assembly 130 includes a light splitting prism 141, a first light guiding assembly 142 and a second light guiding assembly 143, the light splitting prism 141 is disposed on an emergent light path of the illumination assembly 110 for splitting the white light into a first color light 111, a second color light 112 and a third color light 113, and the first light guiding assembly 142 is disposed on the emergent light path of the first color light 111 for guiding the first color light 111 to the first spatial light modulator 151; the second light guide element 143 is disposed on the outgoing light path of the second color light 112, and is used for guiding the second color light 112 to the second spatial light modulator 152; the pre-modulation spatial light modulator 154 is provided on the outgoing light path of the third color light 113. Thereby, the light splitting assembly 130 can split the white light into the first color light 111, the second color light 112, and the third color light 113, and guide the first color light 111, the second color light 112, and the third color light 113 to the first spatial light modulator 151, the second spatial light modulator 152, and the pre-modulation spatial light modulator 154, respectively.

As an example, the first color light 111 is red light, the second color light 112 is blue light, and the third color light 113 is green light. Specifically, the beam splitter prism 141 may be a cross dichroic beam splitter prism formed by gluing four right-angle prisms, the beam splitter prism 141 is plated with a green-transmitting blue-transmitting anti-red film layer and a green-transmitting red-transmitting anti-blue film layer which are crossed with each other, green light directly transmits through the beam splitter prism 141 to the third spatial light modulator 153, blue light is reflected by the beam splitter prism 141 to the second light guide assembly 143, and red light is reflected by the beam splitter prism 141 to the first light guide assembly 142.

In this embodiment, the light splitting prism 141 includes a first color light emitting surface and a second color light emitting surface, the first color light 111 exits through the first color light emitting surface, and the second color light 112 exits through the second color light emitting surface. The first color light emitting surface and the second color light emitting surface are mirror images with respect to a symmetry plane of the beam splitter prism 141, wherein the center of the beam splitter prism 141 is located on the symmetry plane of the beam splitter prism 141, and the symmetry plane of the beam splitter prism 141 is located between the first color light emitting surface and the second color light emitting surface and is parallel to the first color light emitting surface and the second color light emitting surface.

The first light guiding element 142 is connected to the first color light emitting surface, the second light guiding element 143 is connected to the second color light emitting surface, and the first light guiding element 142 and the second light guiding element 143 are mirror images with respect to the symmetry plane of the light splitting prism 141. Thereby, the optical paths of the first color light 111 in the light splitting prism 141 and the first light guiding assembly 142 and the optical paths of the second color light 112 in the light splitting prism 141 and the second light guiding assembly 143 can be made to be mirror images with respect to the symmetry plane of the light splitting prism 141, so that the optical paths of the first color light 111 and the second color light 112 are conjugated. Further, the first spatial light modulator 151 and the second spatial light modulator 152 are mirror images of each other with respect to the symmetry plane of the light splitting prism 141, so that the entire optical path of the first color light 111 before modulation and the entire optical path of the second color light 112 before modulation are conjugate.

In this embodiment, the first light guiding assembly 142 includes a first light guiding pipe 1421, a first light path turning part 1422, a second light guiding pipe 1423 and a second light path turning part 1424, which are connected in sequence, and the first light guiding pipe 1421 is connected to the first color light emitting surface of the light splitting prism 141; the second light guiding assembly 143 includes a third light guiding pipe 1431, a third light path turning member 1432, a fourth light guiding pipe 1433, and a fourth light path turning member 1434, which are connected in sequence, and the third light guiding pipe 1431 is connected to the second color light emitting surface of the light splitting prism 141.

The first light pipe 1421 and the third light pipe 1431 are mirror images of each other about a symmetry plane of the beam splitter prism 141, the first light path turning member 1422 and the third light path turning member 1432 are mirror images of each other about a symmetry plane of the beam splitter prism 141, the second light pipe 1423 and the fourth light pipe 1433 are mirror images of each other about a symmetry plane of the beam splitter prism 141, and the second light path turning member 1424 and the fourth light path turning member 1434 are mirror images of each other about a symmetry plane of the beam splitter prism 141.

The first light path turning part 1422, the second light path turning part 1424, the third light path turning part 1432 and the fourth light path turning part 1434 can be right-angled prisms, two right-angled surfaces of the first light path turning part 1422 are connected to the first light pipe 1421 and the second light pipe 1423 respectively, and the first colored light 111 is incident to the second light pipe 1423 after the inclined surface of the first light path turning part 1422 deflects 90 degrees. One right-angle surface of the second light path turning member 1424 is connected to the second light guide 1423, the other right-angle surface faces the first spatial light modulator 151, and the first color light 111 is deflected by 90 ° on the inclined surface of the second light path turning member 1424 and then enters the first spatial light modulator 151. Two right-angle surfaces of the third light path turning member 1432 are respectively connected to the third light guide pipe 1431 and the fourth light guide pipe 1433, and the second color light 112 is incident to the fourth light guide pipe 1433 after being deflected by 90 degrees on the inclined surface of the third light path turning member 1432. One right-angle surface of the fourth light path turning member 1434 is connected to the fourth light pipe 1433, and the other right-angle surface faces the second spatial light modulator 152, and the second color light 112 is reflected by the inclined surface of the fourth light path turning member 1434 and enters the second spatial light modulator 152 after being deflected by 90 °.

In this embodiment, the pre-modulation spatial light modulator 154 may be disposed on the light path between the third polarizer 173 and the third spatial light modulator 153, the third color light 113 is polarized by the third polarizer 173 and then enters the pre-modulation spatial light modulator 154 in a single polarization state for pre-modulation, and the pre-modulated light enters the third spatial light modulator 153 for modulation. This is because, in the structure shown in fig. 6, the light paths of the first color light 111 and the second color light 112 separated from the light source are mirrored in the light guide, so there is no uniformity problem when combining the light, and the light path of the third color light 113 is not folded, and the uniformity of the light spot is different from the uniformity of the first color light 111 and the second color light 112, and the "face-miss" problem can be solved by adding the pre-modulation spatial light modulator 154, and the specific principle is as described above and will not be described herein again. Meanwhile, due to the addition of the pre-modulation spatial light modulator 154, a polarization device 174 (see fig. 4 in detail) is not required to be arranged between the illumination assembly 110 and the beam splitter prism 141, and the pre-modulation spatial light modulator 154 is directly used for polarization, so that the whole projection system 100 is more compact. That is, the pre-modulation spatial light modulator 154 not only can solve the non-uniformity problem of the third color light 113, but also can polarize it. Of course, in some embodiments, a polarization device 174 may be disposed on the optical path between the illumination assembly 110 and the beam splitter prism 141, and is configured to polarize the white light emitted from the illumination assembly 110 and then enter the beam splitter prism 141 in a single polarization state. For the detailed structure of the illumination assembly 110 and the polarization device 174, reference may be made to the related description of the embodiment shown in fig. 1 and fig. 4, and details are not repeated here.

Although the present application has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (11)

1. A projection system, comprising:

an illumination assembly for providing white light;

the light splitting assembly is arranged on an emergent light path of the lighting assembly and is used for splitting the white light into first color light, second color light and third color light; and

the modulation assembly comprises a first spatial light modulator, a second spatial light modulator, a third spatial light modulator and a premodulation spatial light modulator, wherein the premodulation spatial light modulator is arranged on a light path between the light splitting assembly and the third spatial light modulator; the light splitting component is further used for guiding the first color light to the first spatial light modulator for modulation, guiding the second color light to the second spatial light modulator for modulation, and guiding the third color light to the pre-modulation spatial light modulator for pre-modulation;

the light path of the first colored light and the light path of the second colored light are conjugated; the pre-modulation spatial light modulator is used for pre-modulating the spot uniformity of the third color light according to the spot uniformity of the first color light or the second color light and then transmitting the modulated spot uniformity to the third spatial light modulator.

2. The projection system of claim 1, further comprising a detection unit and a control unit, the detection unit configured to detect a spot uniformity of the first color light or the second color light and generate detection data; the control unit is used for acquiring a pre-modulation signal according to the detection data and sending the pre-modulation signal to the pre-modulation spatial light modulator, and the pre-modulation spatial light modulator is used for pre-modulating the third colored light according to the pre-modulation signal.

3. The projection system of claim 1, wherein the light splitting assembly comprises a first light splitting prism, a first light guide member, a second light guide member, and a second light splitting prism, and the first light splitting prism is disposed on an exit light path of the illumination assembly and is configured to split the white light into a fourth color light and the first color light; the first light guide part is arranged on an emergent light path of the first color light and is used for guiding the first color light to the first spatial light modulator; the second light guide piece and the second light splitting prism are sequentially arranged on an emergent light path of fourth color light, the fourth color light is incident to the second light splitting prism through the second light guide piece and split to form the second color light and the third color light, the second color light is incident to the second spatial light modulator, and the third color light is incident to the pre-modulation spatial light modulator; the light path of the fourth color light is partially overlapped with the light path of the second color light.

4. The projection system of claim 3, wherein the first dichroic prism includes a first dichroic surface and a first color light emitting surface and a fourth color light emitting surface that are mirror images of each other with respect to the first dichroic surface, the white light is split into the first color light and the fourth color light at the first dichroic surface, the first color light is emitted through the first color light emitting surface, and the fourth color light is emitted through the fourth color light emitting surface;

the first light guide part comprises a first light guide pipe and a light path turning part, the first light guide pipe is connected between the first color light emitting surface and the light path turning part, and the light path turning part is used for guiding the first color light to the first spatial light modulator; the second light guide part comprises a second light guide pipe, the second light guide pipe is connected between the fourth color light emitting surface and the second light splitting prism, and the first light guide pipe and the second light guide pipe are mirror images of each other about the first light splitting surface; the second light splitting prism is provided with a second color light emitting surface, and the second color light emitting surface and the light emitting surface of the light path turning piece are mirror images relative to the first light splitting surface.

5. The projection system of claim 4, wherein the first spatial light modulator and the second spatial light modulator are mirror images of each other with respect to the first light splitting plane.

6. The projection system of claim 3, further comprising a first reflector and a second reflector, wherein the first reflector and the second reflector are sequentially disposed on an optical path between the pre-modulation spatial light modulator and the third spatial light modulator, and a light beam emitted from the pre-modulation spatial light modulator is sequentially reflected by the first reflector and the second reflector and then enters the third spatial light modulator.

7. The projection system of claim 3, wherein the modulation assembly further comprises a pre-imaging lens disposed on the optical path between the pre-modulated spatial light modulator and the third spatial light modulator for pre-imaging the light beam emitted from the pre-modulated spatial light modulator.

8. The projection system of any of claims 3-7, wherein the first color light is red light, the second color light is green light, the third color light is blue light, and the fourth color light is yellow light.

9. The projection system of claim 1, wherein the light splitting assembly comprises a light splitting prism, a first light guiding assembly and a second light guiding assembly, the light splitting prism is disposed on the light path of the illumination assembly and is configured to split the white light into a first color light, a second color light and a third color light, and the first light guiding assembly is disposed on the light path of the first color light and is configured to guide the first color light to the first spatial light modulator; the second light guide assembly is arranged on a light path of the second color light and used for guiding the second color light to the second spatial light modulator; the pre-modulation spatial light modulator is arranged on a light path of the third color light.

10. The projection system of claim 9, wherein the first color light is red, the second color light is blue, and the third color light is green.

11. The projection system of claim 1 wherein the pre-modulated spatial light modulator has a resolution less than the third spatial light modulator.

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