A local illumination component based on polarization-selective waveguide

Abstract

The present invention provides a local lighting component based on a polarization-selective waveguide, comprising a lighting component body, a first LED light source, a second LED light source, a polarization liquid crystal control component, and a first polarization-state selective outcoupling beam splitter array and a second polarization-state selective outcoupling beam splitter array located inside the lighting component body. The light output of the local lighting component can be controlled by polarization selectivity and different LED switches, thereby illuminating a specific display area according to the position of the display content, reducing power consumption while improving contrast. The component is particularly suitable for micro-projection systems or projection optical modules.

Description

Technical Field

[0001] The present invention belongs to the technical field of lighting waveguides, and in particular relates to a local lighting component based on a polarization selective waveguide. Background Art

[0002] Since the concepts of virtual reality (VR) and augmented reality (AR) were proposed, the market for near-eye display devices based on VR or AR modes has made great progress. Among the many hardware implementations of AR or VR technology, near-eye display (NED) is the most effective and can provide users with the best experience. Because NEDs need to be worn on the head, their lightness, compactness, and good display quality are particularly important.

[0003] The waveguide system is a representative of the thin and light solutions among the current near-eye display solutions. The thickness of the waveguide is relatively thin, generally within 3mm. The waveguide needs to be used in conjunction with a projection system. To compensate for the low light efficiency of the waveguide, the more mature LCOS optical engine is generally used as a micro-projection system solution. However, due to the passive luminescence characteristics of its liquid crystal, the LCOS optical engine has a low contrast when illuminated by the lighting system. Summary of the Invention

[0004] To solve the above problems, the present invention provides a local lighting component based on a polarization-selective waveguide, which is a waveguide system that can perform local lighting control. The LCOS optical machine equipped with this waveguide system has lower power consumption and higher contrast.

[0005] A local lighting component based on a polarization-selective waveguide includes a lighting component body 101, a first LED light source 105, a second LED light source 106, a polarization liquid crystal control component 104, and a first polarization-state selective outcoupling beam splitter array 102 and a second polarization-state selective outcoupling beam splitter array 103 located within the lighting component body 101.

[0006] The lighting assembly body 101 is a parallel flat plate, and light is transmitted by total internal reflection within the lighting assembly body 101. The first LED light source 105 and the second LED light source 106 are placed at two angles on either side of the end of the lighting assembly body 101, and the polarization liquid crystal control component 104 is located between the first LED light source 105, the second LED light source 106, and the lighting assembly body 101.

[0007] Light emitted by any LED light source is modulated by the polarization liquid crystal control component 104 into linearly polarized light of the first polarization state or the second polarization state, and the polarization directions of the first polarization state and the second polarization state are perpendicular to each other; the linearly polarized light is totally reflected in the lighting component body 101 to the first polarization state selective outcoupling beam splitter array 102 or the second polarization state selective outcoupling beam splitter array 103 for reflection or transmission, so that the light is emitted from different areas and different directions on the surface of the lighting component body 101;

[0008] Among them, the first polarization state selective coupling out-of-coupling spectroscopic surface array 102 is a group of spectroscopic surfaces with polarization selection characteristics, and each spectroscopic surface is coated with a thin film that is transparent to the second polarization state light and has a reflective characteristic for the first polarization state; the second polarization state selective coupling out-of-coupling spectroscopic surface array 103 is a group of spectroscopic surfaces with polarization selection characteristics, and each spectroscopic surface is coated with a thin film that is transparent to the first polarization state light and has a reflective characteristic for the second polarization state.

[0009] Furthermore, when current or voltage is applied to the polarization liquid crystal control component 104 to turn it on, the light emitted by any LED light source is modulated into the second polarization state by the polarization liquid crystal control component 104;

[0010] When no current or voltage is applied to the polarization liquid crystal control component 104 and the polarization liquid crystal control component 104 is in an off state, light emitted by any LED light source is modulated into the first polarization state by the polarization liquid crystal control component 104 .

[0011] Furthermore, the beam splitter films in the first polarization state selective outcoupling beam splitter array 102 and the second polarization state selective outcoupling beam splitter array 103 have angle selectivity and only reflect light within a set angle range.

[0012] Furthermore, the first polarization state selective outcoupling beam splitter array 102 is located above the second polarization state selective outcoupling beam splitter array 103. When the light is in the first polarization state, it is directly reflected by the first polarization state selective outcoupling beam splitter array 102.

[0013] When the light is in the second polarization state, the light passes through the first polarization state selective outcoupling beam splitter array 102 and is incident on the second polarization state selective outcoupling beam splitter array 103 , and then is reflected by the second polarization state selective outcoupling beam splitter array 103 .

[0014] Furthermore, the switch combination of the first LED light source 105, the second LED light source 106 and the two polarization liquid crystal control components 104 corresponds to four different light emission directions;

[0015] When the first LED light source 105 is turned on, the second LED light source 106 is turned off, and the polarization liquid crystal control component 104 is turned on, the light is emitted from the second polarization state selective outcoupling beam splitter array 103 in the upper left direction;

[0016] When the first LED light source 105 is turned off, the second LED light source 106 is turned on, and the polarization liquid crystal control component 104 is turned on, the light is emitted from the second polarization state selective outcoupling beam splitter array 103 in the upper right direction;

[0017] When the first LED light source 105 is turned on, the second LED light source 106 is turned off, and the polarization liquid crystal control component 104 is turned off, the light is emitted from the first polarization state selective outcoupling beam splitter array 102 in the lower left direction;

[0018] When the first LED light source 105 is turned off, the second LED light source 106 is turned on, and the polarization liquid crystal control component 104 is turned on, light is emitted from the first polarization state selective coupling beam splitter array 102 in a lower right direction.

[0019] Furthermore, a localized illumination component based on a polarization-selective waveguide can be used in conjunction with the display screen 203, wherein the display screen 203 is divided into four regions: upper left, upper right, lower left, and lower right, and each region corresponds to a light emitting direction;

[0020] When it is necessary to illuminate the image to be displayed in any area, the corresponding LED light source and polarized liquid crystal control component are turned on or off to achieve local lighting of the set area on the display screen 203.

[0021] Furthermore, a local illumination component based on a polarization-selective waveguide can be used in conjunction with a projection optical lens assembly;

[0022] After being emitted from the surface of the lighting assembly body 101 , the light is shaped by the projection optical lens assembly 202 and then incident on the display screen 203 .

[0023] Beneficial effects:

[0024] The present invention provides a local lighting component based on a polarization-selective waveguide, comprising a lighting component body, a first LED light source, a second LED light source, a polarization liquid crystal control component, and a first polarization-state selective outcoupling beam splitter array and a second polarization-state selective outcoupling beam splitter array located inside the lighting component body. The light output of the local lighting component can be controlled by polarization selectivity and different LED switches, thereby illuminating a specific display area according to the position of the display content, reducing power consumption while improving contrast. The component is particularly suitable for micro-projection systems or projection optical modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A 3D modeling diagram of the local lighting component;

[0026] Figure 2 A light path diagram when the polarization liquid crystal control system provided by the present invention is turned off;

[0027] Figure 3 A light path diagram when the polarization liquid crystal control system provided by the present invention is turned on;

[0028] Figure 4 This is a logic lighting diagram of the LED and polarized liquid crystal control switch provided by the present invention;

[0029] Figure 5 Schematic diagram of a near-eye display system equipped with the local lighting assembly provided by the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0031] like Figure 1 The figure shows a 3D modeling diagram of the local lighting assembly, which includes a lighting assembly body 101, a first LED light source 105, a second LED light source 106, a polarization liquid crystal control assembly 104, and a first polarization state selective outcoupling beam splitter array 102 and a second polarization state selective outcoupling beam splitter array 103 located inside the lighting assembly body 101;

[0032] The lighting assembly body 101 is a parallel flat plate, and light is transmitted by total internal reflection within the lighting assembly body 101. The first LED light source 105 and the second LED light source 106 are placed at two angles on either side of the end of the lighting assembly body 101, and the polarization liquid crystal control component 104 is located between the first LED light source 105, the second LED light source 106, and the lighting assembly body 101.

[0033] Light emitted by any LED light source is modulated by the polarization liquid crystal control component 104 into linearly polarized light of a first polarization state or a second polarization state, and the polarization directions of the first polarization state and the second polarization state are perpendicular to each other. The modulation into the first polarization state or the second polarization state depends on whether current or voltage is applied to the polarization liquid crystal control component. The linearly polarized light is totally reflected in the lighting component body 101 to the first polarization state selective outcoupling beam splitter array 102 or the second polarization state selective outcoupling beam splitter array 103 for reflection or transmission, thereby achieving light emission from different areas and different directions on the surface of the lighting component body 101.

[0034] Among them, the first polarization state selective coupling out-of-coupling spectroscopic surface array 102 is a group of spectroscopic surfaces with polarization selection characteristics, and each spectroscopic surface is coated with a thin film that is transparent to the second polarization state light and has a reflective characteristic for the first polarization state; the second polarization state selective coupling out-of-coupling spectroscopic surface array 103 is a group of spectroscopic surfaces with polarization selection characteristics, and each spectroscopic surface is coated with a thin film that is transparent to the first polarization state light and has a reflective characteristic for the second polarization state.

[0035] like Figure 2 The figure shows a schematic diagram of the optical path when the polarization liquid crystal control system is turned off. The switch of the polarization liquid crystal control system is controlled by the image signal of the display screen. When the polarization liquid crystal is turned off, the light passing through the polarization liquid crystal control component 104 is in the first polarization state. The light is transmitted inside the waveguide and is reflected and emitted by the first polarization state selective coupling splitter array 102. The splitter film of the first polarization state selective coupling splitter array 102 has angle selectivity and only reflects light within a certain angle range, that is, the light emitted away from the LED end as shown in the figure. Figure 3 The figure shows a schematic diagram of the optical path when the polarization liquid crystal control system is activated. At this point, light passes through the polarization liquid crystal control component 104 and changes to the second polarization state. The light propagates through the waveguide. When it encounters the splitting surface of the first polarization state selective outcoupling beam splitter array 102, the light can pass through the splitting surface of the first polarization state selective outcoupling beam splitter array 102 because the film coated on the first polarization state selective outcoupling beam splitter array 102 is transparent to light of the second polarization state. Since the second polarization state selective outcoupling beam splitter array 103 is coated with a reflective film for the second polarization state, this portion of the light is reflected. Similarly, the splitting surface film of the second polarization state selective outcoupling beam splitter array 103 is angularly selective, and the light is emitted toward the end near the LED shown in the figure. Thus, light can be propagated up and down through the control of the polarization liquid crystal and the characteristics of the internal splitting surface film.

[0036] like Figure 2 、 Figure 3 As shown, the entire lighting component has two LEDs, which are divided into two sides of the component. The two LEDs emit light in two directions. The two LEDs are also controlled by the output signal of the display screen. The switching of the LEDs can be independently controlled to realize the left and right refraction of the light of the lighting component.

[0037] Accordingly, according to Figure 2 、 Figure 3 It can be seen that by independently adjusting the LEDs and switching the polarization liquid crystal control system, the light of the lighting assembly can be emitted in four different directions.

[0038] Among them, when the first LED light source 105 is turned on, the second LED light source 106 is turned off, and the polarization liquid crystal control component 104 is turned on, the light is emitted in the upper left direction on the second polarization state selective coupling splitter surface array 103; when the first LED light source 105 is turned off, the second LED light source 106 is turned on, and the polarization liquid crystal control component 104 is turned on, the light is emitted in the upper right direction on the second polarization state selective coupling splitter surface array 103; when the first LED light source 105 is turned on, the second LED light source 106 is turned off, and the polarization liquid crystal control component 104 is turned off, the light is emitted in the lower left direction on the first polarization state selective coupling splitter surface array 102; when the first LED light source 105 is turned off, the second LED light source 106 is turned on, and the polarization liquid crystal control component 104 is turned on, the light is emitted in the lower right direction on the first polarization state selective coupling splitter surface array 102.

[0039] For example, Figure 4 The diagram shows the corresponding relationship between the switching logic of the two LEDs and the polarized liquid crystal control and the illumination areas of the display screen. In actual use, the display screen is divided into four areas. When an image is displayed in one area, such as "ABC" in the diagram, the image information is transmitted to the polarized liquid crystal control system and the LED control system to control the switching so that light only illuminates the "ABC" area, while other areas are not illuminated, thereby improving the overall contrast of the screen. Under this logical control, the two LEDs can be continuously turned on and off as the display image changes, eliminating the need for long-term illumination and reducing power consumption.

[0040] like Figure 5 The figure shows a near-eye display system equipped with the local illumination component. The projection system includes a local illumination component 201, a projection optical lens assembly 202, an LCOS backlight display screen 203, and a near-eye display pupil expansion waveguide 204. After light is emitted from 201, it passes through the projection optical lens assembly and is incident on 202. After being reflected by the display screen 203, it is emitted again through the projection optical lens assembly 202 and is incident on the near-eye display pupil expansion waveguide 204, forming the entire monocular near-eye display module.

[0041] In summary, the present invention provides a local lighting component based on a polarization-selective waveguide, comprising at least two polarization liquid crystal control systems capable of controlling polarization states, at least two independently controllable LEDs with different light-emitting angles, and a planar light-guiding system having an internal optical region with polarization-selective characteristics. The system is used for regional lighting control of passive light-emitting display screens, and can regulate the light output of the local lighting component through polarization selectivity and different LED switches, and can be applied to micro-projection systems or projection optical machine modules.

[0042] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may of course make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A local illumination component based on a polarization-selective waveguide, characterized in that: The invention comprises a lighting component body (101), a first LED light source (105), a second LED light source (106), a polarization liquid crystal control component (104), and a first polarization state selective outcoupling light splitting surface array (102) and a second polarization state selective outcoupling light splitting surface array (103) located inside the lighting component body (101); The lighting component body (101) is a parallel flat plate, and light is totally reflected and propagated inside the lighting component body (101); a first LED light source (105) and a second LED light source (106) are placed at two angles on both sides of the end of the lighting component body (101), and a polarized liquid crystal control component (104) is located between the first LED light source (105), the second LED light source (106) and the lighting component body (101); Light emitted by any LED light source is modulated by a polarization liquid crystal control component (104) to become linearly polarized light in a first polarization state or a second polarization state, and the polarization directions of the first polarization state and the second polarization state are perpendicular to each other; the linearly polarized light is totally reflected in the lighting component main body (101) to the first polarization state selective outcoupling beam splitting surface array (102) or the second polarization state selective outcoupling beam splitting surface array (103) for reflection or transmission, thereby achieving light emission in different areas and in different directions on the surface of the lighting component main body (101); The first polarization state selective outcoupling beam splitting surface array (102) is a group of beam splitting surfaces with polarization selective characteristics, and each beam splitting surface is coated with a thin film that is transparent to the second polarization state light and has a reflective characteristic to the first polarization state; the second polarization state selective outcoupling beam splitting surface array (103) is a group of beam splitting surfaces with polarization selective characteristics, and each beam splitting surface is coated with a thin film that is transparent to the first polarization state light and has a reflective characteristic to the second polarization state.

2. A local lighting component based on a polarization selective waveguide according to claim 1, characterized in that: When a current or voltage is applied to the polarization liquid crystal control component (104) to turn it on, light emitted by any LED light source is modulated into a second polarization state through the polarization liquid crystal control component (104); When no current or voltage is applied to the polarization liquid crystal control component (104) and the component is in a closed state, light emitted by any LED light source is modulated into a first polarization state through the polarization liquid crystal control component (104).

3. The local illumination component based on polarization selective waveguide according to claim 1, characterized in that: The light splitting surface films in the first polarization state selective outcoupling light splitting surface array (102) and the second polarization state selective outcoupling light splitting surface array (103) have angle selectivity and only reflect light within a set angle range.

4. The local illumination component based on polarization selective waveguide according to claim 1, characterized in that: The first polarization state selective outcoupling beam splitter array (102) is located above the second polarization state selective outcoupling beam splitter array (103), and when light is in the first polarization state, it is directly reflected by the first polarization state selective outcoupling beam splitter array (102); When the light is in the second polarization state, the light passes through the first polarization state selective outcoupling beam splitter array (102) and is incident on the second polarization state selective outcoupling beam splitter array (103), and then is reflected out through the second polarization state selective outcoupling beam splitter array (103).

5. The local illumination component based on polarization selective waveguide according to claim 4, characterized in that: The switch combination of the first LED light source (105), the second LED light source (106), and the two polarization liquid crystal control components (104) corresponds to four different light emission directions; When the first LED light source (105) is turned on, the second LED light source (106) is turned off, and the polarization liquid crystal control component (104) is turned on, light is emitted from the second polarization state selective coupling splitter array (103) in an upper left direction; When the first LED light source (105) is turned off, the second LED light source (106) is turned on, and the polarization liquid crystal control component (104) is turned on, light is emitted in an upper right direction on the second polarization state selective coupling splitter array (103); When the first LED light source (105) is turned on, the second LED light source (106) is turned off, and the polarization liquid crystal control component (104) is turned off, light is emitted from the first polarization state selective coupling splitter array (102) in a lower left direction; When the first LED light source (105) is turned off, the second LED light source (106) is turned on, and the polarization liquid crystal control component (104) is turned on, light is emitted in a lower right direction on the first polarization state selective coupling splitter array (102).

6. The local illumination component based on polarization selective waveguide according to claim 5, characterized in that: It can be used in conjunction with a display screen (203), wherein the display screen (203) is divided into four areas: upper left, upper right, lower left, and lower right, and each area corresponds to a light emitting direction; When it is necessary to illuminate an image to be displayed in any area, the corresponding LED light source and polarized liquid crystal control component are turned on or off to achieve local illumination of a set area on the display screen (203).

7. The local illumination component based on polarization selective waveguide according to claim 6, characterized in that: Can be used with projection optical lens set; After being emitted from the surface of the lighting component main body (101), the light is shaped by the projection optical lens group (202) and then incident on the display screen (203).

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