Projection system

Abstract

The projection system includes a light source, a reflective phase modulator, a display, and a projection lens. The light source is configured to emit a first light beam. The reflective phase modulator is configured to adjust a phase of the first light beam to generate a second light beam. The display is configured to receive the second light beam. The display is positioned between the projection lens and the reflective phase modulator.

Description

Technical Field

[0001] This disclosure relates to a projection system. Background Technology

[0002] In projection systems, a common light source is a global beam, which illuminates the display to produce an image on the screen. However, this method cannot prevent darker areas of the displayed image from receiving oblique light (i.e., diffracted or scattered light), making it difficult to improve the brightness difference of the displayed image and thus difficult to improve image contrast.

[0003] Therefore, how to provide a packaging structure that can solve the above problems remains one of the goals that the industry urgently needs to study. Summary of the Invention

[0004] The present disclosure is a projection system.

[0005] In one embodiment of this disclosure, the projection system includes a light source, a reflective phase modulator, a display, and a projection lens. The light source is configured to emit a first light beam. The reflective phase modulator is configured to adjust the phase of the first light beam to generate a second light beam. The display is configured to receive the second light beam. The display is located between the projection lens and the reflective phase modulator.

[0006] In one embodiment of this disclosure, the reflective phase modulator is a silicon-based liquid crystal spatial light modulator.

[0007] In one embodiment of this disclosure, the second beam includes a plurality of local dark bands and a plurality of local bright bands.

[0008] In one embodiment of this disclosure, the display is a microdisplay.

[0009] In one embodiment of this disclosure, the display is a silicon-based liquid crystal display.

[0010] In one embodiment of this disclosure, the display device further includes a computing unit. The computing unit is electrically connected to a reflective phase modulator and a display, wherein the computing unit is configured to control the phase adjustment function of the reflective phase modulator.

[0011] Another technical aspect of this disclosure is a projection system.

[0012] In one embodiment of this disclosure, the projection system includes a light source module, a computing unit, and a microdisplay. The light source module is configured to provide incident light. The light source module includes a light source and a silicon-based liquid crystal spatial light modulator. The light source is configured to emit a first light beam. The silicon-based liquid crystal spatial light modulator is configured to adjust the phase of the first light beam to generate incident light, wherein the incident light includes multiple local dark bands and multiple local bright bands. The computing unit is configured to control the light intensity distribution of the local dark bands and local bright bands of the incident light. The computing unit is electrically connected to the silicon-based liquid crystal spatial light modulator and the microdisplay. The microdisplay is configured to receive the incident light.

[0013] In one embodiment of this disclosure, the projection system further includes a projection lens. A microdisplay is located between the projection lens and the silicon-based liquid crystal spatial light modulator.

[0014] In one embodiment of this disclosure, the microdisplay is a silicon-based liquid crystal display.

[0015] In one embodiment of this disclosure, the computing unit is configured to control the phase adjustment function of a silicon-based liquid crystal spatial light modulator.

[0016] In the above embodiments, since the incident light of the display can be adjusted by a reflective phase modulator, the light intensity of the incident light is redistributed, forming local bright bands and local dark bands. As a result, a smaller amount of diffracted light travels to the dark areas of the displayed image. Therefore, the image contrast is improved. Because the silicon-based liquid crystal spatial light modulator is a reflective element, its adjustment rate is high. Thus, the light intensity distribution of the incident light can adapt to complex images or rapidly changing images displayed on the display. Therefore, the projection system of this disclosure can provide high-contrast images that change constantly. Furthermore, the light intensity distribution of the incident light is controlled by an algorithm. In this way, each color of light from the light source can be redirected to a specific pixel on the image by the algorithm. Therefore, there is no need to use additional light source elements to split beams of different colors, and light loss during light transmission can be reduced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a projection system according to an embodiment of the present disclosure.

[0018] Figure 2 for Figure 1 A schematic diagram of a silicon-based liquid crystal spatial light modulator for a projection system.

[0019] Figure 3 for Figure 1 A schematic diagram of the image displayed on the monitor.

[0020] The reference numerals in the attached figures are explained as follows:

[0021] 100: Projection System

[0022] 110: Light source

[0023] 120: Silicon-based liquid crystal spatial light modulator

[0024] 121: Backplate

[0025] 122: Pixel Electrode

[0026] 123: Liquid Crystal Layer

[0027] 1232: Liquid crystal molecules

[0028] 124: Electrode layer

[0029] 125: Front panel

[0030] 130: Monitor

[0031] 132: Displaying images

[0032] 132B: Relatively Bright Area

[0033] 132D: Relative Dark Area

[0034] 140: Computing Unit

[0035] 150: Polarizing plate

[0036] 160: Projection lens

[0037] LB: Local bright band

[0038] LD: Local dark band

[0039] L1: First beam

[0040] L2: Second beam Detailed Implementation

[0041] The following describes several embodiments of the present invention with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and elements will be shown in the drawings in a simple schematic manner. And for clarity, the thickness of layers and regions in the drawings may be exaggerated, and the same element symbols represent the same elements in the description of the drawings.

[0042] Figure 1This is a schematic diagram of a projection system 100 according to an embodiment of the present disclosure. The projection system 100 includes a light source 110, a liquid crystal on silicon-spatial light modulator (LCOS-SLM) 120, and a display 130. The LCOS-SLM 120 is a reflective phase modulator configured to adjust the light phase. The light source 110 emits a first light beam L1 toward the LCOS-SLM 120, and the first light beam L1 is a global light. The LCOS-SLM 120 adjusts the light phase of the first light beam L1 to generate a second light beam L2. The light intensity distribution of the second light beam L2 forms a pattern determined according to the display screen of the display 130.

[0043] The light source 110 may be an arc lamp, a light source module, or a light-emitting diode (LED) light source. In some embodiments, the light source 110 is a laser light source module, and the light source 110 emits red, green, and blue light in a timing sequence. In some other embodiments, the light source 110 is a laser light source module that emits red, green, and blue light simultaneously, so the first beam L1 can be considered as effective white light.

[0044] Figure 2 for Figure 1 A schematic diagram of a silicon-based liquid crystal spatial light modulator 120 in a projection system 100. The silicon-based liquid crystal spatial light modulator 120 includes a back panel 121, a plurality of pixel electrodes 122, a liquid crystal layer 123, an electrode layer 124, and a front panel 125. The back panel 121 is a complementary metal-oxide-semiconductor (CMOS) substrate. The pixel electrodes 122 are disposed on the back panel 121 and form an array. Three pixel electrodes 122 are illustrated exemplary. Figure 2 In the middle section, the pixel electrode 122 comprises a conductive material, such as aluminum. A liquid crystal layer 123 is disposed between the back panel 121 and the front panel 125, and the liquid crystal layer 123 comprises liquid crystal molecules 1232. An electrode layer 124 is disposed between the liquid crystal layer 123 and the front panel 125. The electrode layer 124 is a transparent conductive layer, such as indium tin oxide (ITO). The front panel 125 is a glass substrate.

[0045] The voltage difference between electrode layer 124 and pixel electrode 122 can drive liquid crystal molecules 1232 in liquid crystal layer 123. Pixel electrode 122 can reflect incident light (first beam L1). The reflected light (second beam L2) passes through liquid crystal layer 123 and front panel 125. In this way, after the incident light (first beam L1) is reflected and penetrates liquid crystal layer 123, the wavefront of the incident light (first beam L1) will change.

[0046] Since the silicon-based liquid crystal spatial light modulator 120 has an array of pixel electrodes 122, the liquid crystal molecules 1232 corresponding to different pixel electrodes 122 can rotate in different ways. In this way, the amount of light that penetrates the liquid crystal layer 123 and is reflected can be controlled by the voltage difference between the pixel electrode 122 and the electrode layer 124. In some embodiments, the width of each pixel electrode 122 is approximately 4 micrometers.

[0047] See Figure 1 In this embodiment, after the global beam (first beam L1) is modulated by the silicon-based liquid crystal spatial light modulator 120, its light intensity is redistributed to form a beam (second beam L2) with local dark bands LD. The second beam L2 includes multiple local bright bands LB and multiple local dark bands LD corresponding to the display image 132 of the display 130. In other words, the second beam L2 is the incident light of the display 130.

[0048] Figure 3 for Figure 1 This is a schematic diagram of the display image 132 of the display 130. The display image 132 includes a relatively bright area 132B and a relatively dark area 132D. As described above, by adjusting the first beam L1, a second beam L2 with a local bright band LB and a local dark band LD can be generated. The local bright band LB of the second beam L2 provides light corresponding to the relatively bright area 132B of the display image 132 of the display 130. The local dark band LD provides light corresponding to the relatively dark area 132D of the display image 132 of the display 130. In other words, a smaller amount of diffracted light travels to the relatively dark area 132D of the display image 132. Therefore, the difference between the relatively dark area 132D and the relatively bright area 132B can be increased, thereby improving the image contrast.

[0049] See Figure 1 The projection system 100 also includes a computing unit 140. The computing unit 140 is electrically connected to the silicon-based liquid crystal spatial light modulator 120 and the display 130. The computing unit 140 can control the pattern of the second beam L2 according to the image displayed in real time on the control display 130.

[0050] Because the silicon-based liquid crystal spatial light modulator 120 is a reflective element, and the thickness of the reflective element (e.g., cellgap) is smaller than that of the transmissive element, the phase adjustment rate of the silicon-based liquid crystal spatial light modulator 120 is high, making the light intensity distribution of the second beam L2 sufficient to adapt to complex images or the rapidly changing images of the display 130. Therefore, the projection system 100 of this disclosure can provide high-contrast images that change at any time.

[0051] The intensity distribution of the second beam L2 is controlled by an algorithm. For example, when the light source 110 contains multi-colored beams emitted in a time sequence, each color beam can be redistributed to form a portion of a beam with a local bright band LB and a portion of a beam with a local dark band LD. In this way, the light of each color can be redirected to a specific pixel on the image by the algorithm. Therefore, the projection system 100 of this disclosure does not require additional light source elements to split beams of different colors, and light loss during light transmission can be reduced.

[0052] See Figure 1 In this embodiment, the display 130 is a liquid crystal on silicon (LCOS) micro-display, but this disclosure is not limited thereto. In other embodiments, the display 130 may be a digital light processing (DLP) projector or a liquid crystal display (LCD). The projection system 100 also includes a polarizing plate 150 and a projection lens 160. In this embodiment, the polarizing plate 150 is a wire grid polarizer, but this disclosure is not limited thereto. In other embodiments, the polarizing plate 150 may be a polarizing beam splitter (PBS). The polarizing plate 150 is disposed between the liquid crystal on silicon spatial light modulator 120, the display 130, and the projection lens 160. The image 132 displayed on the display 130 can be projected onto the screen via the projection lens 160.

[0053] The metal wire grid polarizer comprises numerous fine metal lines distributed on a substrate, with the metal lines having a specific pitch corresponding to the wavelength of the incident light (in this embodiment, the second beam L2). In this embodiment, the second beam L2, modulated by the silicon-based liquid crystal spatial light modulator 120, is split into two parts with different polarization states, such as a parallel polarized (P-polarized) beam and a vertically polarized (S-polarized) beam. The parallel polarized beam can penetrate the polarizer 150, and the polarizer 150 reflects the vertically polarized beam. The parallel polarized beam can be converted into a vertically polarized beam and penetrate the polarizer 150 again. Therefore, the vertically polarized beam from the display 130 can be guided to the projection lens 160 after reflection by the polarizer 150.

[0054] Alternatively, the projection system 100 can be considered as a combination of a light source module, a computing unit 140, and a microdisplay 130. The light source module is configured to provide incident light (the second beam L2) to the microdisplay. The light source module may include a light source 110 configured to emit a first beam L1 and a silicon-based liquid crystal spatial light modulator 120 configured to adjust the phase of the first beam L1 to generate the incident light (the second beam L2).

[0055] In summary, since the incident light to the display can be adjusted by the liquid crystal spatial light modulator, the intensity of the incident light is redistributed, forming local bright and dark bands. As a result, a smaller amount of diffracted light travels to the dark areas of the displayed image. Therefore, the image contrast is improved. Because the silicon-based liquid crystal spatial light modulator is a reflective element, its phase adjustment rate is high. Thus, the intensity distribution of the incident light is sufficient to adapt to complex images or rapidly changing screen displays. Therefore, the projection system of this disclosure can provide high-contrast images that change at any time. Furthermore, the intensity distribution of the incident light is controlled by an algorithm. In this way, each color of light from the light source can be redirected to a specific pixel on the image by the algorithm. Therefore, there is no need to use additional light source elements to split beams of different colors, and light loss during transmission can be reduced.

[0056] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A projection system, comprising: A light source, configured to emit a first beam of light; A reflective phase modulator configured to adjust the phase of the first beam to generate a second beam; A display configured to receive the second beam; A projection lens, wherein the display is positioned between the projection lens and the reflective phase modulator; and A computing unit electrically connected to the reflective phase modulator and the display, wherein the computing unit is configured to control the pattern of the second beam according to an image displayed in real time on the display before the second beam is incident on the display, and the pattern of the second beam includes a plurality of local dark bands and a plurality of local bright bands.

2. The projection system of claim 1, wherein the reflective phase modulator is a silicon-based liquid crystal spatial light modulator.

3. The projection system of claim 1, wherein the display is a microdisplay.

4. The projection system of claim 3, wherein the display is a silicon-based liquid crystal display.

5. The projection system of claim 1, wherein the computing unit is configured to control the phase adjustment function of the reflective phase modulator.

6. A projection system, comprising: A light source module configured to provide an incident light, wherein the light source module includes: A light source, configured to emit a first beam of light; and A silicon-based liquid crystal spatial light modulator is configured to adjust the phase of the first beam to generate the incident light, wherein the incident light includes a plurality of local dark bands and a plurality of local bright bands; A computing unit, wherein the computing unit is configured to control the light intensity distribution of the local dark bands and the local bright bands of the incident light; and A microdisplay configured to receive the incident light, wherein the computing unit is electrically connected to the silicon-based liquid crystal spatial light modulator and the microdisplay, and the computing unit is configured to control the light intensity distribution of some local dark bands and some local bright bands based on an image displayed in real time on the microdisplay before the incident light is incident on the microdisplay.

7. The projection system of claim 6, further comprising: A projection lens, wherein the microdisplay is positioned between the projection lens and the silicon-based liquid crystal spatial light modulator.

8. The projection system of claim 6, wherein the microdisplay is a silicon-based liquid crystal display.

9. The projection system of claim 6, wherein the computing unit is configured to control the phase adjustment function of the silicon-based liquid crystal spatial light modulator.

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