Directional backlit display device

Abstract

The present invention discloses a directional backlit display device. The backlight source includes a light source module and a reflective narrow-angle diffuser. The reflective narrow-angle diffuser has an array of multiple micro-curved mirrors. The reflective narrow-angle diffuser reflects light from the light source module and projects the light into a uniform beam with a narrow diffusion angle. A backlit display panel is placed in the path of the light projection. An image displayed by the backlit display panel is projected onto an eyebox through the light. Each pixel of the image corresponds to at least one micro-curved mirror on the reflective narrow-angle diffuser. Light that penetrates each pixel is evenly diffused into the eyebox, and the diffused areas of all pixels of the backlit display panel overlap with the eyebox.

Description

Technical Field

[0001] The present invention projects a light source onto a reflective narrow-angle diffuser and utilizes the characteristics of a micro-curved mirror array to diffuse the reflected light in a set direction and a narrow angle to generate a uniform directional light beam as a backlight source for a directional backlight display. Background Art

[0002] TFT-LCD panel (Thin Film Transistor-Liquid Crystal Display Panel) is the most common backlit display panel. Its general structure is as follows Figure 1 As shown, there is an external backlight source 91, and a liquid crystal 92 (Liquid Crystal) molecular layer is set between two parallel glass substrates (Glass Substrate). There are two polarization filters 93 (Polarizer) on the outside of both sides with polarization directions perpendicular to each other. Thin-film transistors 94 (TFT) are set on the lower glass substrate, and color filters (CF) are set on the upper glass substrate. The rotation direction of the liquid crystal molecules is controlled by changing the electric field generated by the signal on the TFT. The light from the backlight passes through the first polarization filter, and its polarization direction is perpendicular to the second polarization filter, so it is blocked. If the light passing through the first polarization filter is rotated by the liquid crystal molecules and the polarization direction is changed, then the light can pass through the second polarization filter to display the brightness and color set by the pixel.

[0003] like Figure 2 As shown, in an ideal directional liquid crystal display (LCD), light from every pixel on the LCD screen must reach the entire area of the viewer's eyebox Z, with uniform brightness. In other words, any point within the eyebox Z receives light from every pixel on the LCD screen, with uniform brightness. Therefore, as long as the viewer's eyes are within the eyebox, they can see the entire image; if their eyes are outside the eyebox, they cannot see the image at all.

[0004] Each pixel on the LCD panel of an LCD is usually composed of sub-pixels of red, green, and blue (RGB). By controlling the rotation angle of the liquid crystal molecules in the sub-pixels through the electric field strength, the light intensity passing through the sub-pixels can be controlled. Each pixel determines the final brightness and color of the pixel by controlling the ratio of the three color light intensities of red, green, and blue. However, each sub-pixel is also equivalent to a slit, and the light penetrating each sub-pixel may produce diffraction. Figure 3AAs shown in the figure, when the slit width W1 is much larger than the wavelength λ, the diffraction phenomenon is not obvious, as shown in the figure. Figure 3B As shown in , the closer the slit width W2 is to the wavelength λ, the more obvious the diffraction phenomenon is; and the red, green and blue sub-pixels are usually rectangular, as shown in Figure 4A As shown, one side is long and the other side is short. The long side of the sub-pixel is parallel to Figure 4A When the sub-pixels are arranged in the vertical direction (ie vertical direction) of the image, the short side of each sub-pixel corresponds to the horizontal width W sph , the long side of each sub-pixel corresponds to the vertical width W spv Therefore, the diffraction phenomenon in the horizontal direction will be more obvious than that in the vertical direction. The projection area of the light after passing through the LCD panel will exceed the originally set projection area due to the diffraction of the light. That is, the image can also be seen in the horizontal direction outside the eye box. The horizontal width W sph The smaller it is, the more serious it is.

[0005] The backlight source of liquid crystal displays (LCDs) can use visible light sources such as incandescent bulbs, CCFLs (cold cathode fluorescent lamps), ELs (electroluminescent devices) and LEDs (light-emitting diodes). Depending on the distribution position of the light source, they are divided into side-lit and direct-lit (bottom-backlit) types.

[0006] The direct-lit type (bottom-backlit type) is a flat surface light source, which can be a continuous and uniform surface light source, such as an EL or flat fluorescent lamp, or a light source composed of more point light sources, such as an LED array.

[0007] The advantages of LED backlight are uniform brightness, long service life, low voltage drive, no need for inverter, rich colors and wide color gamut, so it has become the mainstream backlight source for LCD monitors.

[0008] like Figure 5A As shown, the direct-lit backlight source of the LED array will add a light guide plate 97 (Lightguide) and a diffuser 98 (Diffuser) above the LED chip to correct the emission direction and diffusion angle of the light, increase the front brightness and make the light diffuse evenly.

[0009] Since the aforementioned direct-type backlight source is not directional, when a directional backlight source is required, such as a projector or a head-up display (HUD), a cup-shaped collimating lens 99 is added above the LED chip. Figure 5B As shown, this increases light utilization and improves the directionality of the emitted light.

[0010] like Figure 6 As shown, the backlight source 91 is an LED collimator array backlight source formed by arranging a plurality of LEDs with cup-shaped collimators in a longitudinal and transverse direction to achieve the effect of a surface light source.

[0011] However, the gap between two adjacent collimators will become a darker block in the entire surface light source. There will also be differences in brightness between the center and edges of each collimator, making the brightness of the surface light source uneven. Moreover, the collimated light beam emitted by the collimator cannot evenly spread the light of each pixel to any position in the eye box when passing through every pixel of the LCD screen.

[0012] like Figure 7 As shown, in order to make the light emitted by the LED collimator array backlight uniform, a diffuser 98 is added between the TFT-LCD panel and the collimator array to diffuse the light evenly. However, its effect is still limited and it cannot form a completely uniform surface light source. In addition, it causes the brightness of the light to attenuate, resulting in increased power consumption and temperature.

[0013] like Figure 8 As shown, reflective narrow-angle diffusers are used to reflect and diffuse images from projectors (LCD, DLP, or Laser) into the viewer's eyebox, improving light utilization and increasing image brightness. Light from each pixel in the projected image is evenly distributed throughout the eyebox after being reflected and diffused by the reflective narrow-angle diffuser.

[0014] like Figure 9A As shown, the reflective narrow-angle diffuser has an array of multiple micro-concave mirrors 21 arranged in a square or hexagonal honeycomb arrangement. The size of each micro-concave mirror 21 can be between 2.5um and 0.25mm.

[0015] Each micro-concave mirror 21 may have the same or different curvatures and angles.

[0016] The number of micro-concave mirrors on a reflective narrow-angle diffuser is unlimited and can be adjusted according to the resolution and optical path design requirements. For example, the number can reach hundreds of thousands (480p: 640×480 = 307,200, 720p: 1280×720 = 921,600), millions (FHD: 1920×1080 = 2.073,600, 2K: 2560×1440 = 3,680,400, 4K: 3840×2160 = 8,294,400), or even higher.

[0017] like Figure 9B As shown, the reflective narrow-angle diffuser can be a flat surface or a curved surface, and has a plurality of micro-concave mirrors 21 on one side of the flat surface or the curved surface.

[0018] like Figure 10A As shown, a general plane reflector has a flat and smooth surface. The incident angle of the incident light is equal to the reflection angle of the reflected light, so there is no diffusion effect. As a result, the diffusion angle of the light beam remains unchanged, and the viewing angle is limited.

[0019] like Figure 10B As shown, if the projection screen is a flat surface, in order to allow viewers at all angles to see it, a wide surface scattering is required. The light projected on the plane will diffuse in all directions (i.e., the diffusion angle is θ1), but the brightness of the viewed image will be greatly reduced.

[0020] like Figure 10C As shown, the micro-concave mirror on the reflective narrow-angle diffuser can diffuse the incident light toward a set direction at a set narrow angle, thereby reflecting the light to the set direction and greatly improving the brightness of the light within the diffusion angle θ2 range. Summary of the Invention

[0021] The present invention provides a directional backlight display device, comprising:

[0022] a light source module, projecting a light;

[0023] a reflective narrow-angle diffuser having an array of multiple micro-curved mirrors, which reflects the light and projects it into a uniform beam with a narrow diffusion angle;

[0024] A backlit display panel is positioned along the path of light projected from the reflective narrow-angle diffuser to a viewer. An image displayed on the backlit display panel is projected by the light onto a projection area (i.e., corresponding to the viewer's eyeboxes). Each pixel of the image corresponds to at least one micro-curved mirror on the reflective narrow-angle diffuser, allowing light from each pixel to be evenly diffused into the projection area. The reflective narrow-angle diffuser adjusts the projection angle and diffusion angle of the light for all pixels so that the diffused areas overlap with the projection area. Hundreds of thousands or even millions of pixels on the backlit display panel experience the same diffusion pattern.

[0025] In such a setting, the light reflected by the reflective narrow-angle diffuser is already projected onto the backlit display panel in a uniformly diffused manner, and it is not necessary to arrange a light homogenizer in the light path.

[0026] The color sub-pixels of each pixel on the backlit display panel are arranged with the long sides of the sub-pixels perpendicular to the up-down direction (ie, the vertical direction) of the backlit display panel, which can reduce horizontal diffraction and prevent other viewers from seeing the image.

[0027] In addition, the multiple micro-curved mirrors of the reflective narrow-angle diffuser can be micro-concave mirrors, micro-convex mirrors, or a combination of micro-concave mirrors and micro-convex mirrors. The reflective narrow-angle diffuser can be used to adjust the size range, viewing brightness, and angular position of the projection area.

[0028] In addition, a plano-convex cylindrical lens or a biconvex cylindrical lens is further included between the reflective narrow-angle diffuser and the light source module to reshape the originally circular projection light area of the light source module into an elliptical shape to meet the requirements of a rectangular eye box.

[0029] In addition, a plano-convex hyperbolic lens or a biconvex hyperbolic lens, i.e., a lens with curvature in two axes, is included between the reflective narrow-angle diffuser and the light source module to adjust the originally circular projection light area of the light source module to a nearly rectangular shape, which better meets the requirements of a rectangular eye box.

[0030] In addition, at least one reflective lens is included between the reflective narrow-angle diffuser and the light source module to change the direction of the light path, making the use of space more flexible.

[0031] In addition, the light source module is a high-wattage LED, an LED array, an LED with a collimator, or an LED array with a collimator LED.

[0032] In addition, the size range, viewing brightness, and angle position of the projection area can be adjusted by the light source module.

[0033] In addition, the projection path of the backlit display panel further includes a concave mirror and a windshield. The light carrying the image is reflected and amplified by the concave mirror and the windshield, and finally projected onto the eye boxes of the viewer.

[0034] The present invention further provides a directional backlit auto-stereoscopic 3D display device, comprising:

[0035] a first light source module, projecting a first light;

[0036] a second light source module, projecting a second light;

[0037] a reflective narrow-angle diffuser having an array of multiple micro-curved mirrors, the reflective narrow-angle diffuser reflecting the first light and the second light and projecting the first light and the second light into uniform beams with narrow diffusion angles;

[0038] A backlit display panel is positioned along a path where the first and second light rays are projected from the reflective narrow-angle diffuser to a viewer. The backlit display panel alternately displays a left-eye parallax image and a right-eye parallax image in a time-multiplexed manner. The first light source module and the second light source module alternately project the first and second light rays. The left-eye parallax image is projected onto a projection area corresponding to the viewer's left eye (i.e., a left-eye eyebox) via the first light, and the right-eye parallax image is projected onto a projection area corresponding to the viewer's right eye (i.e., a right-eye eyebox) via the second light. The projection of the first and second light rays is synchronized with the timing of displaying the left-eye parallax image and the right-eye parallax image. A period of total darkness occurs between the intersections of the first and second light rays, corresponding to an image switching delay of the backlit display panel. The time for image switching is shorter than the persistence of vision of the human eye, allowing the viewer's left eye to perceive the left-eye parallax image as continuously being seen, while the right eye to perceive the right-eye parallax image as continuously being seen, resulting in a stereoscopic image in the viewer's mind. The color sub-pixels of each pixel on the backlit display panel are arranged with the long sides of the sub-pixels perpendicular to the vertical direction of the backlit display panel, which can reduce horizontal diffraction and prevent the left eye from seeing the right eye parallax image or the right eye from seeing the left eye parallax image.

[0039] In addition, a plano-convex cylindrical lens or a biconvex cylindrical lens is further included between the reflective narrow-angle diffuser and the two light source modules to reshape the originally circular projection light areas of the first light source module and the second light source module into elliptical shapes to meet the requirements of a rectangular eye box.

[0040] In addition, a plano-convex hyperbolic lens or a biconvex hyperbolic lens, i.e., a lens having curvature in two axes, is included between the reflective narrow-angle diffuser and the two light source modules. This reshapes the originally circular projection light areas of the first light source module and the second light source module into a nearly rectangular shape, which better meets the requirements of a rectangular eye box.

[0041] In addition, at least one reflective lens is included between the reflective narrow-angle diffuser and the light source module to change the direction of the light path, making the use of space more flexible.

[0042] The first light source module and the second light source module are a high-wattage LED, an LED array, an LED with a collimator, or an LED array with a collimator.

[0043] In addition, the size range, viewing brightness, and angle position of the projection area for the left eye and the right eye can be adjusted by the light source module.

[0044] In addition, the projection path displayed by the backlit display panel further includes a concave mirror and a windshield. The first light carrying the left-eye parallax image is reflected and amplified by the concave mirror and the windshield before being projected onto the left-eye eye box. The second light carrying the right-eye parallax image is reflected and amplified by the concave mirror and the windshield before being projected onto the right-eye eye box.

[0045] The present invention further provides a directional backlight dual display device, comprising:

[0046] a first light source module, projecting a first light;

[0047] a second light source module, projecting a second light;

[0048] a reflective narrow-angle diffuser having an array of multiple micro-curved mirrors, the reflective narrow-angle diffuser reflecting the first light and the second light and projecting the first light and the second light into uniform beams with narrow diffusion angles;

[0049] A backlit display panel is positioned along a path where the first and second light beams are projected from the reflective narrow-angle diffuser toward a first viewer and a second viewer. The backlit display panel alternately displays a first image and a second image in a time-multiplexed manner. The first light source module and the second light source module alternately project the first and second light beams. The first image is projected onto a projection area between the first viewer's eyes (i.e., a first eyebox), and the second image is projected onto a projection area between the second viewer's eyes (i.e., a second eyebox). The projection of the first and second light beams is synchronized with the timing of displaying the first and second images. A period of total darkness occurs between the intersection of the first and second light beams, corresponding to an image switching delay of the backlit display panel. The image switching time is shorter than the persistence of vision of the human eye, allowing the first viewer to simultaneously view the first image and the second viewer to simultaneously view the second image. The first viewer cannot see the second image, and the second viewer cannot see the first image. The color sub-pixels of each pixel on the backlit display panel are arranged with the long sides of the sub-pixels perpendicular to the vertical direction of the backlit display panel, reducing horizontal diffraction and preventing the first viewer from seeing the second image or the second viewer from seeing the first image.

[0050] In addition, a plano-convex cylindrical lens or a biconvex cylindrical lens is further included between the reflective narrow-angle diffuser and the two light source modules to reshape the originally circular projection light areas of the first light source module and the second light source module into elliptical shapes to meet the requirements of a rectangular eye box.

[0051] In addition, a plano-convex hyperbolic lens or a biconvex hyperbolic lens, i.e., a lens having curvature in two axes, is included between the reflective narrow-angle diffuser and the two light source modules. This reshapes the originally circular projection light areas of the first light source module and the second light source module into a nearly rectangular shape, which better meets the requirements of a rectangular eye box.

[0052] In addition, at least one reflective lens is included between the reflective narrow-angle diffuser and the light source module to change the direction of the light path, making the use of space more flexible.

[0053] The first light source module and the second light source module are a high-wattage LED, an LED array, an LED with a collimator, or an LED array with a collimator.

[0054] The size range, viewing brightness, and angle position of the projection area can be adjusted by the light source module.

[0055] In addition, the projection path displayed by the backlit display panel further includes a concave mirror and a windshield. The first light beam carrying the first image is reflected and amplified by the concave mirror and the windshield before being projected onto the first binocular eye box. The second light beam carrying the second image is reflected and amplified by the concave mirror and the windshield before being projected onto the second binocular eye box. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram of the TFT-LCD panel structure.

[0057] Figure 2 Schematic diagram of an ideal directional TFT-LCD display.

[0058] Figure 3A 、 Figure 3B Schematic diagram of slit diffraction phenomenon.

[0059] Figure 4A 、 Figure 4B Schematic diagram of the pixel and color sub-pixel arrangement structure of a TFT-LCD panel.

[0060] Figure 5A 、 Figure 5B Schematic diagram of the backlight source of TFT-LCD.

[0061] Figure 6 Schematic diagram of LED collimator array backlight source.

[0062] Figure 7 Schematic diagram of the LED collimator array backlight homogenization for TFT-LCD.

[0063] Figure 8Schematic diagram of applying a reflective narrow-angle diffuser to projected images.

[0064] Figure 9A 、 Figure 9B Schematic diagram of the reflective narrow-angle diffuser structure.

[0065] Figure 10A 、 Figure 10B 、 Figure 10C Schematic diagram of the diffusion of projection light on different reflective surfaces.

[0066] Figure 11 FIG. 1 is a schematic diagram of the light path of the directional backlight according to the first embodiment.

[0067] Figure 12A 、 Figure 12B FIG. 1 is a schematic diagram of a TFT-LCD directional backlight display device according to a first embodiment.

[0068] Figure 13A 、 Figure 13B 、 Figure 13C A schematic diagram illustrating the placement of a TFT-LCD display panel.

[0069] Figure 14A 、 Figure 14B 、 Figure 14C FIG. 1 is a schematic diagram of a TFT-LCD directional backlit auto-stereoscopic 3D display device according to a second embodiment.

[0070] Figure 15A 、 Figure 15B FIG. 2 is a schematic diagram of the use of the second embodiment.

[0071] Figure 16A 、 Figure 16B 、 Figure 16C FIG. 1 is a schematic diagram of a TFT-LCD directional backlight dual display device according to a third embodiment.

[0072] Figure 17A 、 Figure 17B This is a schematic diagram of the use of the third embodiment.

[0073] Figure 18 Schematic diagram of the eye box and projection light area.

[0074] Figure 19 Schematic diagram for adjusting the projection light area.

[0075] Figure 20 Another diagram showing the adjustment of the projection light area.

[0076] Figure 21 Schematic diagram of the light source module.

[0077] Figure 22A 、 Figure 22B 、 Figure 22C 、 Figure 23A 、 Figure 23B 、 Figures 24 to 27 Schematic diagram of the eye box.

[0078] Explanation of reference numerals: 1, 11, 12, 101, 102, 103, 104 - light source module; 13, 15 - LED; 14, 16 - LED array; 19 - light diffusion area; 2, 20 - reflective narrow-angle diffuser; 21, 210 - micro-concave mirror; 3 - TFT-LCD display panel; 31, 32, 33 - pixel; 4 - concave mirror; 5 - windshield; 61 - plano-convex cylindrical lens; 62 - biconvex cylindrical lens; 63 - plano-convex hyperbolic lens; 64 - biconvex hyperbolic lens; θ1, θ2 - diffusion angle; G - image; G1, G2 - parallax image; G11 - first image; G12 - second image; L, L1, L2 - light; E1 - left eye; E2 - right eye; P, P1, P2 - viewer; RZ - projected light area; W1, W2 - slit width; W ph - horizontal width in pixels; W sph -sub-pixel horizontal width; W spv -sub-pixel vertical width; Z-eye box; ZL-left eye box; ZR-right eye box; Zp1-first eye box; Zp2-second eye box; Z1, Z2, Z3, Z4-projection area; 91-external backlight; 92-liquid crystal; 93-polarizing filter; 94-thin film transistor; 95-color filter; 96-liquid crystal display; 97-light guide plate; 98-diffuser; 99-collimator. DETAILED DESCRIPTION

[0079] The following description defines the direction of light projection as forward to conform to the common understanding of technicians.

[0080] like Figure 11 to Figure 1 The first embodiment shown in FIG3 is a TFT-LCD directional backlight display device, comprising:

[0081] A light source module 1 projects a light beam L;

[0082] A reflective narrow-angle diffuser 2 includes an array of multiple micro-concave mirrors 21. The reflective narrow-angle diffuser 2 reflects the light L and projects it into a uniform beam with a narrow diffusion angle. In other words, after each micro-concave mirror 21 reflects the light L, the reflected light L is projected in a predetermined direction to form a light diffusion area. In other embodiments, the micro-concave mirrors 21 may be replaced with other micro-curved mirrors, such as micro-convex mirrors.

[0083] like Figure 11As shown, the light source module 1 projects the light L onto the reflective narrow-angle diffuser 2 and utilizes a plurality of micro-concave mirrors 21 to diffuse the light L toward a set direction and a narrow angle, thereby generating a directional light source with uniform brightness.

[0084] like Figure 12A As shown, a TFT-LCD display panel 3 is placed on the path of the light L reflected by the reflective narrow-angle diffuser 2 and projected onto a viewer. An image G displayed on the TFT-LCD display panel 3 is projected onto a projection area (i.e., the eye box Z corresponding to the viewer's eyes) by the light L. Each pixel of the image G corresponds to at least one micro-concave mirror 21 on the reflective narrow-angle diffuser 2. Figure 12B As shown, the light of each pixel can be evenly diffused to the eye box Z. The diffusion areas of all pixels corresponding to the image G overlap with the eye box Z at the designed distance. Hundreds of thousands or millions of pixels on the TFT-LCD display panel 3 have the same diffusion situation. Figure 4B As shown, the color sub-pixels (Sub-Pixels) of each pixel (Pixel) on the TFT-LCD display panel 3, such as the red, green and blue (RGB) sub-pixels (Sub-Pixels), are arranged with the long side of the sub-pixels perpendicular to the vertical direction of the backlight display panel, increasing the horizontal width W of each sub-pixel sph , reducing horizontal diffraction and preventing other viewers nearby from seeing the image.

[0085] In this case, as long as the eyes move within the eye box Z, the complete image G can be seen. If the eyes are outside the range of the eye box Z, the image G cannot be seen at all.

[0086] The size of any micro-concave mirror 21 of the reflective narrow-angle diffuser 2 is smaller than or equal to any pixel 31 of the image G. The reflective narrow-angle diffuser 2 can be used to adjust the size range, viewing brightness, and angular position of the projection area Z. Figure 13A As shown, when the TFT-LCD display panel 3 is placed at the focal length of the micro-concave mirror 21 of the reflective narrow-angle diffuser 2, one pixel 31 of the image G is larger than or equal to the light diffusion area 19, and the light L projected by the micro-concave mirror 21 onto the pixel 31 can be diffused to the entire eye box Z. Figure 13B As shown, when the distance between the TFT-LCD display panel 3 and the micro-concave mirror 21 is greater than the focal length, one pixel 31 of the image G is smaller than the light diffusion area 19 of the micro-concave mirror 21 at that location. Therefore, the light L projected onto the pixel 31 by using multiple micro-concave mirrors 21 can be diffused to the entire eye box Z. Figure 13CAs shown, when the TFT-LCD display panel 3 is placed at a distance less than the focal length of the micro-concave mirror 21, one pixel 31 of the image G is larger than the light diffusion area 19 of the micro-concave mirror 21 at that location. Therefore, the light L projected onto that pixel 31 by a single micro-concave mirror 21 can diffuse throughout the entire eyebox Z. Similarly, even if the light diffusion area 19 of the light L projected onto the image G by a single micro-concave mirror 21 corresponds to multiple pixels, the aforementioned effect can be achieved as long as the image G remains within the reflected light of the reflective diffuser. Therefore, the TFT-LCD display panel 3 can be positioned anywhere along the path of the light L between (the reflection path of) the reflective narrow-angle diffuser 2 and the eyebox Z of the viewer's eyes.

[0087] The backlight used in a typical non-directional TFT-LCD has a light field directionality defined by the field directionality of the electromagnetic wave energy. The FWHM (Full Width at Half Maximum) of the light field emitted by the non-directional backlight is approximately ±30 to ±60° or wider, meaning the diffusion angle is approximately ±30 to ±60° or wider, resulting in a wider viewing angle for the projected image.

[0088] if Figure 11 to Figure 1 The backlight source constructed in the directional backlight display device of the embodiment shown in FIG3 has a light field FWHM of approximately ±5 to ±10° or narrower, that is, a (narrow) diffusion angle of approximately ±5 to ±10° or narrower, thereby narrowing the viewing angle of the projected image. However, in this embodiment or other embodiments, the narrow diffusion angle is not limited to a specific angle defined by other methods.

[0089] The TFT-LCD directional backlight display device further includes a concave mirror and a windshield disposed in the path of the light L in front of the TFT-LCD display panel 3. The light carrying the image is then reflected and amplified by the concave mirror and the windshield before being projected onto the eye box Z of the viewer's eyes.

[0090] like Figure 14A 、 Figure 14B 、 Figure 14C The second embodiment shown is a TFT-LCD directional backlight display device suitable for forming auto-stereoscopic 3D images, comprising:

[0091] A first light source module 11 projects a first light beam L1;

[0092] a second light source module 12, projecting a second light beam L2;

[0093] a reflective narrow-angle diffuser 2 having an array of multiple micro-concave mirrors 21 thereon. The reflective narrow-angle diffuser 2 reflects the first light L1 and the second light L2 and projects the first light L1 and the second light L2 into uniform beams with narrow diffusion angles;

[0094] A TFT-LCD display panel 3 is placed on the path of the first light L1 and the second light L2 projected from the reflective narrow-angle diffuser 2 to a viewer P. The TFT-LCD display panel 3 alternately displays a left-eye parallax image G1 and a right-eye parallax image G2 in a time-multiplexed manner. The first light source module 11 and the second light source module 12 alternately project the first light L1 and the second light L2. Figure 14A As shown, the left eye parallax image G1 is projected onto the projection area corresponding to the left eye E1 of the viewer P by the first light L1 (as shown in FIG. Figure 15A The left eye box ZL is shown. Figure 14B As shown, the right eye parallax image G2 is projected onto the projection area corresponding to the right eye E2 of the viewer P by the second light L2 (as shown in FIG. Figure 15B The right-eye eye box ZR shown in FIG. 1 projects the first light L1 and the second light L2 in synchronization with the timing of displaying the left-eye parallax image G1 and the right-eye parallax image G2. There is a period of total darkness between the intersection of the first light L1 and the second light L2, corresponding to the image switching delay of the TFT-LCD display panel 3. The image switching time is shorter than the persistence of vision of the human eye, which is approximately one-fifteenth of a second. For example, if the left and right eye images are alternately displayed at a frequency of 60 Hz, resulting in a left-eye frame rate (FPS) of 30 Hz and a right-eye frame rate (FPS) of 30 Hz, the viewer P will not perceive image flicker. Using a single TFT-LCD display panel 3, the viewer's left eye E1 can perceive the left-eye parallax image G1 as continuously being viewed, while the right eye E2 can perceive the right-eye parallax image G2 as continuously being viewed, resulting in a stereoscopic image in the viewer's mind. Alternatively, the left and right eye images can be alternately displayed at a higher frequency, such as 90 Hz or 120 Hz, resulting in a smoother and more seamless transition between the images.

[0095] like Figure 4B As shown, the color sub-pixels (Sub-Pixels) of each pixel (Pixel) on the TFT-LCD display panel 3, such as the red, green and blue (RGB) sub-pixels (Sub-Pixels), are arranged with the long side of the sub-pixels perpendicular to the vertical direction of the backlight display panel, increasing the horizontal width W of each sub-pixel sph , reducing diffraction in the horizontal direction, avoiding the left eye seeing the right eye parallax image, or the right eye seeing the left eye parallax image.

[0096] The left-eye parallax image G1 and the right-eye parallax image G2 may be located in the same area or different areas on the TFT-LCD display panel 3 . The left-eye parallax image G1 and the right-eye parallax image G2 may be of the same size or of different sizes.

[0097] like Figure 15A As shown, the TFT-LCD directional backlight display device further includes a concave mirror 4 and a windshield 5. The first light L1 carrying the left eye parallax image G1 is reflected and amplified by the concave mirror 4 and the windshield 5, and finally projected onto the projection area corresponding to the viewer's left eye box ZL. Figure 15B As shown, the second light L2 carrying the right eye parallax image G2 is then reflected and amplified by the concave mirror 4 and the windshield 5 , and finally projected onto the projection area corresponding to the eye box ZR of the viewer's right eye.

[0098] like Figure 16A 、 Figure 16B 、 Figure 16C The third embodiment shown is a TFT-LCD directional backlight display device suitable for forming a dual display screen, comprising:

[0099] A first light source module 11 projects a first light beam L1;

[0100] a second light source module 12, projecting a second light beam L2;

[0101] a reflective narrow-angle diffuser 2 having an array of multiple micro-concave mirrors 21 thereon. The reflective narrow-angle diffuser 2 reflects the first light L1 and the second light L2 and projects the first light L1 and the second light L2 into uniform beams with narrow diffusion angles;

[0102] A TFT-LCD display panel 3 is placed on the path of the first light L1 and the second light L2 projected from the reflective narrow-angle diffuser 2 to a first viewer P1 and a second viewer P2. The TFT-LCD display panel 3 alternately displays a first image G11 and a second image G12 in a time-multiplexed manner. The first light source module 11 and the second light source module 12 alternately project the first light L1 and the second light L2. The first image G11 is projected by the first light L1 onto the projection area corresponding to the eyes of the first viewer P1 (i.e., the projection area). Figure 17A The second image G12 is projected onto the projection area of the eyes of the second viewer P2 (i.e., the first eye box Zp1) by the second light L2. Figure 17BA second eye box Zp2 is provided, and the projection of the first light L1 and the second light L2 is synchronized with the timing of displaying the first image G11 and the second image G12. There is a dark period between the intersection of the first light L1 and the second light L2, corresponding to the image switching delay of the TFT-LCD display panel 3. The time of image sequential switching is shorter than the persistence of vision of the human eye, so the viewer does not perceive image flicker. Therefore, a single TFT-LCD display panel 3 can be used to allow the first viewer P1 to view the first image G11 and the second viewer P2 to view the second image G12 simultaneously. The first viewer P1 cannot see the second image G12, and the second viewer P2 cannot see the first image G11.

[0103] like Figure 4B As shown, the color sub-pixels (Sub-Pixels) of each pixel (Pixel) on the TFT-LCD display panel 3, such as the red, green and blue (RGB) sub-pixels (Sub-Pixels), are arranged with the long side of the sub-pixels perpendicular to the vertical direction of the backlight display panel, increasing the horizontal width W of each sub-pixel sph , reducing diffraction in the horizontal direction, preventing the first viewer from seeing the second image, or the second viewer from seeing the first image.

[0104] like Figure 16B As shown, the TFT-LCD directional backlight display device further includes a windshield 5 disposed between the paths of the first light L1 and the second light L2 traveling from the TFT-LCD display panel 3 to the first viewer P1 and the second viewer P2. The first light L1 carrying the first image G11 is projected onto the windshield 5, then reflected by the windshield 5, and finally projected onto the first eye box Zp1 of the first viewer P1's eyes (as shown in FIG. Figure 17A As shown), the second light L2 carrying the second image G12 is projected onto the windshield 5, and then reflected by the windshield 5, and finally projected onto the second eye box Zp2 of the second viewer P2's eyes (as shown Figure 17B As shown), the first viewer P1 is allowed to view the first image G11 while the second viewer P2 is allowed to view the second image G12. The first viewer P1 cannot see the second image G12, and the second viewer P2 cannot see the first image G11.

[0105] like Figure 16C As shown, the TFT-LCD directional backlight display device is Figure 16B Compared with the embodiment of the present invention, a concave mirror 4 is further included between the TFT-LCD display panel 3 and the windshield 5. Figure 17AAs shown, the first light L1 carrying the first image G11 is projected onto the concave mirror 4, is reflected and magnified by the concave mirror 4, is then projected onto the windshield 5, is reflected by the windshield 5, and finally projects onto the first eye box Zp1 of the first viewer P1. Figure 17B As shown, the second light L2 carrying the second image G12 is projected onto the concave mirror 4, reflected and magnified by the concave mirror 4, and then projected onto the windshield 5, reflected by the windshield 5, and finally projected onto the second eye box Zp2 of the second viewer P2's eyes, allowing the first viewer P1 to view the first image G11 while also allowing the second viewer P2 to view the second image G12. However, the first viewer P1 cannot see the second image G12, and the second viewer P2 cannot see the first image G11.

[0106] like Figure 18 As shown, generally speaking, the projection area (i.e., the eye box Z) ultimately produced by the light source module 1 is usually required to be rectangular. However, the projection light zone RZ composed of the light L projected by the light source module 1 is not rectangular, but usually circular. Therefore, part of the light L that exceeds the range of the eye box Z is wasted on the optical path.

[0107] like Figure 19 As shown, in order to increase the brightness of the viewed image and improve the utilization rate of the projected light, the aforementioned embodiments may include a plano-convex cylindrical lens 61 or a biconvex cylindrical lens 62 located between the reflective narrow-angle diffuser 2 and the light source module 1, so as to reshape the originally circular projected light zone RZ into an elliptical shape to meet the requirements of the rectangular eye box.

[0108] like Figure 20 As shown, in order to increase the brightness of the viewed image and improve the utilization rate of the projected light, the aforementioned embodiments may also include a plano-convex hyperbolic lens 63 or a biconvex hyperbolic lens 64 located between the reflective narrow-angle diffuser 2 and the light source module 1, that is, a lens with curvature in two axes, which reshapes the originally circular projected light zone RZ into a shape that is approximately rectangular, which better meets the requirements of a rectangular eye box.

[0109] In addition, at least one reflective lens is included between the reflective narrow-angle diffuser and the light source module to change the direction of the light path, making the use of space more flexible.

[0110] like Figure 21 As shown in the aforementioned embodiments, the first light source module 11 and the second light source module 12 can be a high-wattage LED 13, an LED array 14, an LED with a collimator 15, or an LED array 16 with a collimator LED. These light source modules can generate directional light sources after being reflected by the reflective narrow-angle diffuser 2.

[0111] Figures 22A to 27 The various embodiments shown are used to illustrate how to design or adjust the size range, viewing brightness, and angle position of the projection area.

[0112] like Figure 22A In the illustrated embodiment, a first light source module 11 projects a first light beam L1 onto a reflective narrow-angle diffuser 2. A TFT-LCD display panel 3 has three pixels 31, 32, and 33. The first light beam L1 is reflected and diffused by the array of micro-concave mirrors 21 on the reflective narrow-angle diffuser 2, then penetrates the three pixels 31, 32, and 33 of the TFT-LCD display panel 3 and is then projected and diffused into a first projection area Z1. In this embodiment, the dimensions of the first projection area Z1 correspond to the dimensions of the eye box Z. As long as the eye is within the first projection area Z1, the three pixels 31, 32, and 33 of the TFT-LCD display panel 3 can be viewed.

[0113] by Figure 22A Based on the size range of the first projection area Z1, when constructing an eye box Z with a projection area twice the size (i.e., the first projection area Z1 plus the second projection area Z2), the following can be used: Figure 22B Compared with Figure 22A The implementation mode of Figure 22B In one embodiment, a reflective narrow-angle diffuser 20 is employed, comprising an array of micro-concave mirrors 210 with varying curvatures and angles. This causes the first light beam L1 to be reflected and diffused by the reflective narrow-angle diffuser 2, then pass through the three pixels 31, 32, and 33 of the TFT-LCD display panel 3. The light is then projected and diffused into the eyebox Z defined by the first projection area Z1 and the second projection area Z2. As long as the eye is within the first projection area Z1 and the second projection area Z2, the three pixels 31, 32, and 33 of the TFT-LCD display panel 3 can be viewed. However, this approach effectively disperses the light source of the first light beam L1 into the eyebox Z, reducing the brightness of the image by half.

[0114] If you want to construct an eye box Z with twice the size based on the size range of the first projection area Z1, you can also use Figure 22C In this embodiment, the Figure 22AThe invention also includes a reflective narrow-angle diffuser 2 having the same curvature as the reflective narrow-angle diffuser 2, and simultaneously uses a first light source module 11 and a second light source module 12. The first light source module 11 projects a second light ray L1 onto the reflective narrow-angle diffuser 2. The first light ray L1 is reflected and diffused by the array of micro-concave mirrors 21 on the reflective narrow-angle diffuser 2, then penetrates the three pixels 31, 32, and 33 of the TFT-LCD display panel 3, and then projects and diffuses to the first projection area Z1 corresponding to the eye box Z. The second light source module 12 projects a second light ray L2 onto the reflective narrow-angle diffuser 2. The second light ray L2 is reflected and diffused by the array of micro-concave mirrors 21 on the reflective narrow-angle diffuser 2, then penetrates the three pixels 31, 32, and 33 of the TFT-LCD display panel 3, and then projects and diffuses to the second projection area Z2 corresponding to the eye box Z. In this way, as long as the eyes are within the range of the first projection area Z1 and the second projection area Z2, the three pixels 31, 32, and 33 of the TFT-LCD display panel 3 can be viewed, and the image brightness is the same as that of the first projection area Z1 and the second projection area Z2. Figure 22A The implementation is the same, and the brightness will not be halved due to doubling the size of the eye box Z.

[0115] Using multiple light source modules for the same reflective narrow-angle diffuser means adding multiple incident light rays at different angles. Each light source module will diffuse the light at different angles. Therefore, the smaller the light source area, the smaller the diffused eye box area, and the larger the light source area, the larger the diffused eye box area.

[0116] like Figure 23A and Figure 23B In the illustrated embodiment, the size range of the eye box Z is composed of a first projection area Z1 and a second projection area Z2 of equal size. Each projection area Z1, Z2 is produced by a separate light source module. Specifically, the two projection areas Z1, Z2 are arranged side by side to form the eye box Z. A first light source module 101 forms a corresponding first projection area Z1, and a second light source module 102 forms a corresponding second projection area Z2. As long as the eye sees the same image within the eye box Z, the first light source module 101 and the second light source module 102 simultaneously project light, equivalent to having the brightness of two light sources within the eye box Z.

[0117] like Figure 24 In the embodiment shown, the eye box Z is formed by continuously arranging four projection areas side by side, wherein a first light source module 101 forms a first projection area Z1, a second light source module 102 forms a second projection area Z2, a third light source module 103 forms a third projection area Z3, and a fourth light source module 104 forms a fourth projection area Z4. Figure 25As shown, when the first light source module 101, the second light source module 102, the third light source module 103 and the fourth light source module 104 project light at the same time, it is equivalent to having the brightness of four light sources in the long eye box Z, and the eyes see the same picture in this eye box Z.

[0118] like Figure 26 In the embodiment shown, the eye box Z is arranged in a matrix with four projection areas. A first light source module 101 forms a first projection area Z1, a second light source module 102 forms a second projection area Z2, a third light source module 103 forms a third projection area Z3, and a fourth light source module 104 forms a fourth projection area Z4. Figure 27 As shown, when the first light source module 101 , the second light source module 102 , the third light source module 103 and the fourth light source module 104 project light at the same time, it is equivalent to having the brightness of four light sources in the projection area of the matrix eye box Z.

[0119] The implementation of the combination and arrangement of projection areas to form the eye box size is not limited to the examples given here and can be changed according to needs.

Claims

1. A directional backlight display device, characterized in that: Include: a light source module, projecting a light; a reflective narrow-angle diffuser having an array of multiple micro-curved mirrors, the reflective narrow-angle diffuser reflecting the light and projecting the light into a uniform beam with a narrow diffusion angle; and A backlit display panel is positioned in a path of the light projected by the reflective narrow-angle diffuser. An image displayed by the backlit display panel is projected onto a projection area by the light. Each pixel of the image corresponds to at least one micro-curved mirror on the reflective narrow-angle diffuser. Light projected onto each pixel is evenly diffused into the projection area, and the diffusion areas of all pixels of the backlit display panel overlap with the projection area. In which, there are multiple light source modules, at least two of which project a first light and a second light respectively, and the reflective narrow-angle diffuser reflects the first light and the second light, and projects the first light and the second light into uniform beams with the narrow diffusion angle respectively; the backlight display panel is placed on the path where the first light and the second light are projected by the reflective narrow-angle diffuser, and when the first light passes through the backlight display panel, the image is projected onto the projection area, and when the second light passes through the backlight display panel, the image is projected onto another projection area.

2. The directional backlight display device according to claim 1, wherein: The color sub-pixels of each pixel on the backlight display panel are arranged with the long sides of the sub-pixels perpendicular to the up-down direction of the backlight display panel.

3. The directional backlight display device according to claim 1, wherein: A plano-convex cylindrical lens or a biconvex cylindrical lens is included between the reflective narrow-angle diffuser and the light source module to adjust the projection light area of the light source module into an elliptical shape.

4. The directional backlight display device according to claim 1, wherein: A plano-convex hyperbolic lens or a biconvex hyperbolic lens is included between the reflective narrow-angle diffuser and the light source module to adjust the projection light area of the light source module into a shape approximately rectangular.

5. The directional backlight display device according to claim 1, wherein: The light source module includes a high-wattage LED, an LED array, an LED with a collimator, or an LED array with a collimator LED.

6. The directional backlight display device according to claim 1, wherein: The path further includes a windshield for projecting the image onto the projection area.

7. The directional backlight display device according to claim 1, wherein: The path further includes a concave mirror for projecting the image onto the projection area.

8. The directional backlight display device according to claim 1, wherein: The reflective narrow-angle diffuser is used to adjust the size range, viewing brightness and angle position of the projection area.

9. The directional backlight display device according to claim 1, wherein: The light source module is used to adjust the size range, viewing brightness and angle position of the projection area.

10. The directional backlight display device according to claim 1, wherein: At least one reflective lens is further included between the reflective narrow-angle diffuser and the light source module.

11. The directional backlight display device according to claim 1, wherein: A portion of the image displayed by the backlit display panel is a left-eye parallax image, and the other portion is a right-eye parallax image.

12. The directional backlight display device according to claim 1, wherein: The backlit display panel alternately displays a left-eye parallax image and a right-eye parallax image in a time-multiplexed manner. The light source module projects the first light and the second light in synchronization with the timing of the backlit display panel displaying the left-eye parallax image and the right-eye parallax image, respectively. There is a period of complete darkness between the intersections of the first light and the second light, corresponding to the image conversion delay of the backlit display panel, and the image timing switching time is less than the visual persistence time.

13. The directional backlight display device according to claim 1, wherein: A portion of the image displayed by the backlight display panel is a first binocular image, and the other portion is a second binocular image.

14. The directional backlight display device according to claim 1, wherein: The backlit display panel alternately displays a first binocular image and a second binocular image in a time-multiplexed manner. The light source module projects the first light and the second light in synchronization with the timing of the backlit display panel displaying the first binocular image and the second binocular image, respectively. There is a period of complete darkness between the intersections of the first light and the second light, corresponding to the image switching delay of the backlit display panel. The image switching time is shorter than the persistence of vision.

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