A mixed light surface light source for liquid crystal display with variable color gamut

Abstract

The present invention discloses a mixed light surface light source for a liquid crystal display with a variable color gamut. The mixed light source includes a light guide plate, an annular or fan-shaped coherent light generating device, a coherent light generator, and an incoherent light generator. The surface of one side of the light guide plate has a non-total reflection structure and a recessed structure, and the sidewall of the recessed structure serves as the incident surface for the annular coherent light or the fan-shaped coherent light. The coherent light generated by the coherent light generator is totally reflected by the non-total reflection structure on any surface of the light guide plate, and the coherent light and incoherent light are finally transmitted out of the light guide plate by the non-total reflection structure on the light guide plate. In a low color gamut display environment, incoherent light or a mixture of incoherent light and at least one coherent light is used to illuminate the light guide plate. In a high color gamut display environment, only coherent light is used to illuminate the light guide plate. The present invention can solve the problems of forming a surface light source by mixing coherent and incoherent light sources and the excessive energy consumption of coherent lasers.

Description

Technical Field

[0001] The invention relates to a surface light source for a liquid crystal display, and in particular to an energy-saving mixed surface light source for a portable liquid crystal display. Background Art

[0002] Portable displays have been widely used in consumer products such as mobile phones and tablet computers. Currently, the light sources of all portable displays are LEDs or OLEDs.

[0003] LED or OLED are incoherent light sources and are inferior to coherent lasers in terms of color display.

[0004] Tri-color lasers are the optimal display lighting source available to humanity. Laser light sources boast the ability to cover over 75.8% of the human eye's perceptible color gamut, and their extremely narrow spectrum width allows for high-resolution digital encoding without overlapping colors. This is a physical advantage that existing incoherent light sources like LEDs lack.

[0005] The LED spectrum is extremely wide (<30nm), while the laser spectrum is extremely narrow (>5nm). Therefore, the light emitted by the LED is incoherent light; the light emitted by the laser diode or other lasers is coherent light.

[0006] Therefore, in order to improve the color gamut coverage of displays, there are currently plans to use coherent light and incoherent light for lighting sources, especially for projection display devices. This has become a very common technical route in the industry. After focusing the incoherent light from red and green LEDs, it is mixed with blue coherent lasers through a coated reflector to form white light, thereby improving the color gamut of the projector while reducing the spatial coherent speckle of the laser on the projection screen. This requires first focusing the "incoherent light - Lambertian light source LED" to form a near-point light source, and then integrating the light with the "coherent Gaussian or flat-top laser point light source" to obtain white lighting light.

[0007] However, in the field of surface light sources, especially portable displays, there is no mature technical solution that can combine Lambertian incoherent light and Gaussian coherent light - that is, LED and laser - to form a uniform surface light source for liquid crystal displays or other lighting fields.

[0008] At the same time, since the electro-optical conversion efficiency of semiconductor coherent light sources is lower than that of semiconductor incoherent light sources, if portable LCD display devices such as mobile phones, laptops, and tablets use coherent light sources as display light sources, the use time of related products will be shortened. Summary of the Invention

[0009] In view of this, the present invention provides a mixed light surface light source for a liquid crystal display with variable color gamut, which can simultaneously solve the problems that portable electronic display devices are difficult to achieve large color gamut display, coherent light sources and incoherent light sources are mixed together to form a surface light source, and coherent laser energy consumption is too high to be used in portable displays.

[0010] A mixed light surface light source for a liquid crystal display with variable color gamut, comprising a light guide plate, a coherent light beam expander, a coherent light generator, and an incoherent light generator, wherein the coherent light beam expander is used to generate annular or fan-shaped coherent light;

[0011] The surface of one side of the light guide plate has a non-total reflection structure and a concave structure, and the side wall of the concave structure is the incident surface of the annular coherent light or the fan-shaped coherent light;

[0012] The coherent light generating device is correspondingly arranged at the recessed structure, the incoherent light generator is located opposite to the side surface of the light guide plate, the coherent light generated by the coherent light generator is irradiated on the coherent light beam expander, and the coherent light beam expander generates annular or fan-shaped coherent light. The coherent light generated by the coherent light generator is totally reflected on any surface of the light guide plate except the part with total reflection structure, and the coherent light and the incoherent light are finally transmitted out of the light guide plate by the non-total reflection structure on the light guide plate;

[0013] In a low color gamut display environment, incoherent light or a mixture of incoherent light and at least one coherent light is used to illuminate the liquid crystal display screen; in a high color gamut display environment, only coherent light is used to illuminate the liquid crystal display screen.

[0014] Furthermore, after the annular or fan-shaped coherent light is incident on the light guide plate, the normal angle A between any annular or fan-shaped coherent light component and any light-emitting surface of the light guide plate unless the part has a total reflection structure and the normal angle B between any annular or fan-shaped coherent light and any side surface of the light guide plate satisfy the total reflection relationship.

[0015] Furthermore, when the side surface of the light guide plate is the incident surface of the annular or fan-shaped coherent light, there is at least one groove on the side surface of the light guide plate, and the groove wall is the incident surface of the fan-shaped coherent light, so that after the fan-shaped coherent light is incident on the light guide plate, "the angle A between any fan-shaped coherent light component and the normal corresponding to any light-emitting surface and the astigmatism surface of the light guide plate unless there is a total reflection structure" satisfies the total reflection relationship.

[0016] Furthermore, the incoherent light is incident from any thickness surface of the light guide plate, and a reflective device is present on the non-incident thickness surface of the light guide plate for reflecting the incoherent light.

[0017] Furthermore, there is an optical device with at least one of the following optical functions: "reflection", "refraction", "scattering", "diffraction", "polarization", "transmission", and "stimulated emission fluorescence" in the optical path between the coherent light generator and the incoherent light generator and the liquid crystal display screen and the liquid crystal display housing, or a combination of devices with the above optical functions, to generate uniform mixed illumination light.

[0018] Furthermore, the coherent light refers to light with at least one central wavelength between 150 and 12,000 nm that can produce spatial coherence as an illumination light source; and the incoherent light refers to light with at least one central wavelength between 150 and 12,000 nm that cannot produce spatial coherence as an illumination light source.

[0019] Furthermore, the output energies of the coherent light and the incoherent light are jointly controlled by electronic software and electronic hardware, so that the coherent light and the incoherent light can be changed in brightness or turned off separately.

[0020] Furthermore, the coherent light and incoherent light emitting devices are cooled jointly or individually by liquid cooling, gas cooling, semiconductor device cooling and non-forced cooling.

[0021] Furthermore, the hybrid surface light source is used in a display system or a lighting system, and the hybrid surface light source of a portable liquid crystal display is used in a non-portable liquid crystal display device, a projection display, and a lighting source in a single or array form.

[0022] Beneficial effects:

[0023] 1. The present invention processes a non-total reflection structure and a recessed structure on the surface of one side of the light guide plate, uses a coherent light generator and an incoherent light generator to illuminate the corresponding position of the light guide plate, and selects the illumination method according to the high and low color gamut display environments. This can solve the technical problem of mixing coherent light sources and incoherent light sources to form a surface light source.

[0024] 2. The present invention forms a surface light with a simple structure by combining laser coherent light and LED incoherent light for liquid crystal display illumination or lamp illumination, which not only solves the problems of working energy consumption and working time of large color gamut and high energy consumption coherent light sources in portable liquid crystal display devices, but also solves the problem of insufficient color display of existing portable liquid crystal displays using low energy consumption incoherent light sources.

[0025] 3. Users can use low-energy, low-color gamut LEDs as lighting in low-color gamut display environments, or a mixture of LEDs and monochromatic lasers to save energy and extend the use time of portable LCD displays. In entertainment, medical, and other environments that require high-color gamut display, three-primary-color lasers can be used as display lighting to comprehensively improve the color gamut, color saturation, and display effects of portable LCD displays.

[0026] 4. The present invention enables the application of the mixed light source of coherent light source and incoherent light source not only in large-screen projection display, but also in portable liquid crystal displays, liquid crystal displays and other lighting fields, and has broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the appearance structure of the mixed light surface light source of the present invention;

[0028] Figure 2 This is the light path diagram of the mixed light surface light source of the present invention;

[0029] Figure 3 A schematic diagram of a horn-shaped ring laser generating device;

[0030] Figure 4 Schematic diagram of the structure of the light guide plate and the annular coherent light generating device;

[0031] Figure 5 、 6 This is an embodiment of using a fan-shaped coherent light generating device.

[0032] Among them, 1-light guide plate, 11-side wall, 12-non-total reflection structure, 15-reflective device, 2-coherent light expander, 21-conical hollow total reflection surface, 22-laser reflection surface, 3-coherent light generator, 4-incoherent light generator, 41-PCB structure, 43-annular incoherent light generating device, 45-incoherent light guide plate incident surface, 5-optical shaping device. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0034] As attached Figure 1 and 2 As shown, the present invention provides a mixed light surface light source for a liquid crystal display with variable color gamut, comprising a light guide plate 1, a coherent light beam expander 2, a coherent light generator 3 and an incoherent light generator 4.

[0035] In this embodiment, the coherent light generator 3 is a red, green and blue primary color semiconductor laser, and the incoherent light generator 4 is a yellow LED lamp array.

[0036] like Figure 1 As shown, there is at least one recessed through hole on the light guide plate 1, and the generatrix of the conical recessed side wall 11 forms a 45° angle with a length*width surface of the light guide plate 1, which is the annular coherent light incident surface of the light guide plate 1.

[0037] The coherent light beam expander 2 is a cylindrical glass structure with a conical hollow total reflection surface 21. After the collimated coherent light beam enters the coherent light beam expander 2, it irradiates the conical hollow total reflection surface 21 and generates a ring-shaped coherent light with a propagation direction of 135° to the optical axis of the collimated laser beam.

[0038] The outer surface of the coherent light generating device 2 is a 45° conical surface, which is the light emitting surface of the coherent light beam expander 2. The light emitting surface of the coherent light beam expander 2 is closely connected with the conical recessed side wall 11 on the light guide plate 1.

[0039] This solution allows the ring laser beam at an angle of 135° to the optical axis of the collimated laser beam to pass vertically through the light-emitting surface of the coherent light beam expander 2 and vertically enter the light guide plate 1 through the conical recessed side wall 11.

[0040] The incoherent light generators 4 are arranged in a column on the PCB structure 41. Light is incident from the thickness surface of the light guide plate 1, forming an edge-type surface light source.

[0041] like Figure 2 As shown, the angle A between any annular coherent light or fan-shaped coherent light component incident on the light guide plate 1 and the normal corresponding to the coherent light component on any length*width surface of the light guide plate 1, and the angle B between any annular coherent light or fan-shaped coherent light component and the normal corresponding to the coherent light component on any length / width*thickness surface of the light guide plate 1, satisfy A≥arcsin(1 / n) and B≥arcsin(1 / n).

[0042] The coherent light in the light guide plate 1 irradiates the non-total reflection structure 12 on the light guide plate 1 during propagation, and then exits the light guide plate 1 after being diffusely reflected or scattered, forming a coherent light surface light source.

[0043] The incoherent light in the light guide plate 1 irradiates the non-total reflection structure 12 on the light guide plate 1 during propagation, and then exits the light guide plate 1 after being diffusely reflected or scattered, forming an incoherent light surface light source.

[0044] Optical films or plates such as reflective films, prism films, light-homogenizing films, and fluorescent films are attached to or adjacent to the two longest and widest surfaces of the light guide plate 1 and other thick surfaces except the light incident surface.

[0045] The coherent light generator 3 emits laser light with a central wavelength between 150 and 12000 nm. In this embodiment, the coherent light generator 3 includes blue light of 400 to 490 nm, green light of 500 to 560 nm, and red light of 600 to 690 nm. The three primary color lasers are synthesized into a uniform white coherent light surface light source after entering the light guide plate 1.

[0046] The incoherent light generator 4 is a fluorescent light with a central wavelength between 150 nm and 12000 nm. In this embodiment, the incoherent light is a yellow LED array with a central wavelength of 570 nm.

[0047] When users use LCD display products, the control software automatically identifies the color requirements of the displayed application, and jointly regulates the output energy or shuts down of the three-primary color laser and LED through electronic software and circuit hardware to achieve changes in the brightness, color gamut, and color saturation of the LCD screen.

[0048] For example, when a user uses a laptop with this light source for common tasks that don't require a high color gamut display, such as editing documents or browsing the web, only the yellow LED and blue laser work together to create a narrow-gamut white light to illuminate the LCD screen. When performing image processing, gaming, or watching movies, which require high color saturation and a wide color gamut, the yellow LED is turned off, and the three primary colors of laser light illuminate the LCD screen.

[0049] In this solution, the coherent light generator 3 and the incoherent light generator 4 share a heat sink, and heat is dissipated by gas cooling, liquid cooling, heat pipe, semiconductor refrigeration or natural heat dissipation.

[0050] The laser surface light source disclosed in this solution is used in lighting fields such as liquid crystal display backlight, lamp lighting, and projection display.

[0051] The mixed surface light sources proposed in this solution are combined to form a surface light source array, which can be used as a backlight surface light source for zoned light control of large-size non-portable liquid crystal displays.

[0052] The light guide plate 1 is made of a light-transmitting plastic material having a refractive index greater than 1 or a light-transmitting inorganic material having a refractive index greater than 1.

[0053] At least one non-total reflection structure 12 on the light guide plate 1 is made into a destructible total reflection structure of coherent light and incoherent light in the light guide plate 1 by laser dotting, mechanical etching, chemical etching, mold stamping / hot pressing, ink printing, etc., so that the coherent light and incoherent light can be emitted from the light guide plate 1 and form a surface light source.

[0054] The hollow conical reflecting surface 21 on the coherent light expander 2 may have a structure for destructive coherent light to be fully reflected in the annular coherent light generating device 2 by laser dotting, mechanical etching, chemical etching, mold stamping / hot pressing, ink printing, or other shapes to form a uniform light field.

[0055] The hollow conical reflective surface 21 of the coherent light beam expander 2 can be made of a high-reflective film material coated with laser light, or filled with a high-reflectivity filler to become a solid reflector.

[0056] The outer shape of the coherent light beam expander 2 is not limited to the cylindrical shape given in this embodiment. The hollow conical reflecting surface 21 of the coherent light beam expander 2 is not limited to the conical shape given in this embodiment.

[0057] As attached Figure 3 As shown, in this embodiment, the light guide plate 1 is made of polycarbonate and has at least one recessed sidewall 11. The generatrix of the recessed sidewall 11 forms a 45° angle with a length-to-width face of the light guide plate 1. The coherent light beam expander 2 is made of glass and has a high laser damage threshold. The coherent light beam expander 2 is horn-shaped, with a smooth 45° bevel on the outer surface of the horn. The coherent light beam expander 2 is assembled into a recessed through-hole in the light guide plate 1.

[0058] like Figure 4 As shown, the coherent light generator 3 emits an initial laser beam, which is collimated by the optical shaping device 5 and then enters the coherent light beam expander 2 through the small opening of the tapered through hole. The collimated laser beam is irradiated on the hollow conical reflective surface 21 of the coherent light beam expander 2 and is expanded into a ring laser. The ring laser is then totally reflected by the laser reflective surface 22 on the coherent light beam expander 2. After being reflected by the laser reflective surface 22, the ring laser passes through the overlapping surface of the ring laser generating device 2 and the recessed sidewall 11 on the light guide plate 1 and enters the light guide plate 1.

[0059] An angle A is formed between any component of the ring laser after entering the light guide plate and the normal of the laser component on any two length*width surfaces of the light guide plate 1, where A≥arcsin(1 / n).

[0060] In order to ensure the utilization rate of coherent light and incoherent light, and to eliminate the influence of errors and finish of each component in the processing process, which may cause coherent light and incoherent light to leak out of the three thickness surfaces of the light guide plate 1 and reduce the light utilization rate, reflective devices are installed on the three incoherent light incident surfaces of the light guide plate 1, and the emitting device is not shown in the figure.

[0061] The laser beam in the light guide plate 1 irradiates the non-total reflection structure 12 on the light guide plate 1 during the propagation process, and then exits the light guide plate 1 after being diffusely reflected or scattered.

[0062] Optical film materials or plates such as a reflective film, a prism film, a light-uniform film, and a fluorescent film are attached to or adjacent to the two non-thickness surfaces of the light guide plate 1 .

[0063] The laser 3 emits a laser with a central wavelength between 150 and 12000 nm. In this embodiment, the laser 3 includes blue light of 400 to 490 nm, green light of 500 to 560 nm, and red light of 600 to 690 nm. The three primary colors of laser light are synthesized into a uniform white laser beam before entering the light guide plate 1, and then enter the coherent light expander 2.

[0064] The mixed light surface light source disclosed in this solution is used in lighting fields such as non-portable liquid crystal display backlight, lamp lighting, and projection display.

[0065] Multiple mixed light surface light sources are used to form an array to achieve an adjustable backlight source for large-size laser liquid crystal flat panel displays.

[0066] As attached Figure 5 and 6 As shown, in this embodiment, when coherent light enters the light guide plate 1 from the side of the light guide plate 1, the optical axis of the initial light beam from the coherent light generator 3 is parallel to the side of the light guide plate 1, and the initial light beam irradiates the coherent light expander 2 to generate 180° fan-shaped coherent light.

[0067] A reflective device 15 is attached to the side surface of the light guide plate 1 , and the reflective device 15 reflects the coherent light and incoherent light exiting the light guide plate back to the light guide plate.

[0068] The fan-shaped coherent light enters the light guide plate 1 from the concave sidewall 11 on the side surface of the light guide plate 1 .

[0069] The coherent light generator 3 and the incoherent light generator 4 are located on the same side of the light guide plate 1 .

[0070] Incoherent light is incident from the non-thickness surface of the light guide plate 1. There is at least one hole on the non-thickness surface of the light guide plate 1 for incoherent light to enter the light guide plate 1, and the sidewall of the hole is the incoherent light incident surface 45 of the light guide plate.

[0071] The Lambertian light emitted by the incoherent light generator 4 is irradiated onto the annular incoherent light generating device 43 to generate annular incoherent light, which then enters the light guide plate 1 through the incoherent light guide plate incident surface 45 .

[0072] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A mixed light surface light source for a liquid crystal display with variable color gamut, characterized in that: The mixed light surface light source includes a light guide plate, a ring-shaped or fan-shaped coherent light generating device, a coherent light generator and an incoherent light generator; The surface of one side of the light guide plate has a non-total reflection structure and a concave structure, and the side wall of the concave structure is the incident surface of the annular coherent light or the fan-shaped coherent light; The annular or fan-shaped coherent light generating device is correspondingly arranged at the recessed structure, and the incoherent light generator is located opposite to the side surface of the light guide plate. The coherent light generated by the coherent light generator is totally reflected on any part of the light guide plate that is not a "non-total reflection structure". Finally, both the coherent light and the incoherent light are transmitted out of the light guide plate through the non-total reflection structure on the light guide plate. In a low color gamut display environment, incoherent light or a mixture of incoherent light and at least one coherent light is used to illuminate the liquid crystal display; in a high color gamut display environment, only coherent light is used to illuminate the liquid crystal display; After the annular or fan-shaped coherent light generated by the annular or fan-shaped coherent light generating device is incident on the light guide plate, the angle A between any annular or fan-shaped coherent light component and the normal corresponding to the portion on any light exit surface of the light guide plate except for the total reflection structure and the angle B between any annular or fan-shaped coherent light and the normal corresponding to any side surface of the light guide plate satisfy the total reflection relationship.

2. The mixed light surface light source for liquid crystal display with variable color gamut according to claim 1, characterized in that: When the side wall of the recessed structure is the incident surface of the light guide plate for annular or fan-shaped coherent light, after the annular or fan-shaped coherent light is incident on the light guide plate, "the normal angle A between any annular or fan-shaped coherent light component and any light-emitting surface and astigmatism surface of the light guide plate except for the part with total reflection structure" and "the normal angle B between any annular or fan-shaped coherent component and any thickness surface of the light guide plate" satisfy the total reflection relationship.

3. The mixed light surface light source for liquid crystal display with variable color gamut according to claim 2, characterized in that: In the optical path between the coherent light generator and the incoherent light generator and the liquid crystal display screen and the liquid crystal display housing, there is an optical device with at least one of the following optical functions: "reflection", "refraction", "scattering", "diffraction", "polarization", "transmission", "stimulated emission fluorescence", or a combination of devices with the above optical functions.

4. The mixed light surface light source for liquid crystal display with variable color gamut according to claim 3, characterized in that: The coherent light refers to light with at least one central wavelength between 150 and 12,000 nm that can produce spatial coherence as an illumination light source; the incoherent light refers to light with at least one central wavelength between 150 and 12,000 nm that cannot produce spatial coherence as an illumination light source.

5. The mixed light surface light source for liquid crystal display with variable color gamut according to claim 4, characterized in that: The output energy of the coherent light and the incoherent light is jointly controlled by electronic software and electronic hardware, so that the coherent light and the incoherent light can be changed in brightness or turned off separately.

6. The mixed light surface light source for liquid crystal display with variable color gamut according to claim 5, characterized in that: The coherent light and incoherent light emitting devices are cooled jointly or individually by liquid cooling, gas cooling, semiconductor device cooling and non-forced cooling.

7. The mixed light surface light source for liquid crystal display with variable color gamut according to claim 6, characterized in that: The mixed light surface light source is used for display and lighting. The energy-saving mixed light surface light source of a portable liquid crystal display can be used as a non-portable liquid crystal display device, projection display and lighting light source in a single or array form.

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