WO2020057150A1 - 投影系统及投影显示方法 - Google Patents

投影系统及投影显示方法 Download PDF

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Publication number
WO2020057150A1
WO2020057150A1 PCT/CN2019/086925 CN2019086925W WO2020057150A1 WO 2020057150 A1 WO2020057150 A1 WO 2020057150A1 CN 2019086925 W CN2019086925 W CN 2019086925W WO 2020057150 A1 WO2020057150 A1 WO 2020057150A1
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Prior art keywords
light
brightness
light source
illumination
signal
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PCT/CN2019/086925
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English (en)
French (fr)
Inventor
余新
胡飞
吴超
李屹
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深圳光峰科技股份有限公司
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Priority to US17/277,884 priority Critical patent/US11448949B2/en
Priority to EP19861754.0A priority patent/EP3855734B1/en
Publication of WO2020057150A1 publication Critical patent/WO2020057150A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3161—Modulator illumination systems using laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2013—Plural light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2053—Intensity control of illuminating light
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
    • H04N9/3111—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3155—Modulator illumination systems for controlling the light source
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3164—Modulator illumination systems using multiple light sources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3167—Modulator illumination systems for polarizing the light beam
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3179—Video signal processing therefor
    • H04N9/3182—Colour adjustment, e.g. white balance, shading or gamut
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/208—Homogenising, shaping of the illumination light
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/28—Reflectors in projection beam

Definitions

  • the present invention relates to the field of optical imaging technology, and in particular, to a projection system and a projection display method.
  • the high dynamic range (HDR) projection system can increase the contrast and peak brightness of the projector output, so that the bright and dark fields in the picture can display rich grayscale information, which greatly improves the picture effect and the viewing experience of the audience.
  • the first way for existing projection systems to achieve high dynamic range is to use dual spatial light modulators in series to control the light emitted by the light source to achieve a high dynamic range display effect.
  • the HDR of two spatial light modulators is currently used. Due to the addition of a new spatial light modulator in the projection system, the problem of low light efficiency is common. Its light efficiency is about 36% of that of ordinary projection systems. The lower light efficiency makes the projection system achieve higher peak brightness. difficult.
  • Another method is to use two projection systems, one displaying a standard contrast picture, and the other displaying a high-brightness component used to brighten the highlights to achieve high-peak brightness display.
  • the minimum black that can be achieved in the picture The field brightness is limited by the projector that produces the standard contrast picture, so that the brightness of the black field of the projection system using this technology is still high, thereby reducing the contrast and viewing physical examination.
  • the present invention provides a projection system and a projection display method capable of overcoming the above problems.
  • a projection system including:
  • a first light source is an array light source, the first light source is divided into a plurality of illumination areas, and each illumination area can be independently controlled so that the first light source generates first and second lights that can be modulated in light and darkness field;
  • a second light source comprising a light-emitting unit and a light-guiding element; the light-guiding element is used to redistribute the illumination light emitted by the light-emitting unit to produce a second illumination light field that is modifiable in brightness and darkness; The light field and the first illumination light field are superimposed to generate a composite light field;
  • Processing unit executing software modules include:
  • a first light source brightness control module configured to generate a brightness distribution signal corresponding to the illumination area of the first light source according to at least a pixel gray signal of an image frame to be projected and the maximum brightness of the first light source, and output the brightness distribution signal to An illumination area of the first light source to generate the first illumination light field;
  • a second light source brightness control module configured to generate a brightness distribution signal for controlling the light guide element according to a grayscale signal of the image frame and a brightness distribution signal corresponding to the illumination area of the first light source to control the light
  • a guide element generates the second illumination light field
  • a spatial light modulator configured to modulate the composite light field according to an image signal output by the processing unit to generate image light carrying image information.
  • a projection display method including:
  • a spatial light modulator is illuminated with the composite light field, so that the spatial light modulator outputs image light carrying image information under the control of an image signal corresponding to the image frame.
  • the projection system and projection display method provided by the present invention, because the first light source can generate a first illumination light field, and because the first illumination light field includes an array of light sources, each illumination area of the first light source It can independently control its brightness, so that it can generate a light and dark distribution and adjustable first illumination light field according to the picture content.
  • the first illumination light field can reduce the brightness of the dark field part of the picture as required, thereby increasing the contrast of the projection system.
  • the second light source can also generate a light and dark distribution and adjustable second illumination light field through the light guide technology.
  • the light guide technology can increase the brightness of the bright field of the picture, thereby increasing the color gradation and brightness of the bright field portion.
  • the first illuminating light field and the second illuminating light field are combined in front of the spatial light modulator to form a composite illuminating light field to illuminate the spatial light modulator. High contrast projection system.
  • FIG. 1 is a schematic block diagram of a projection system according to a preferred embodiment of the present invention.
  • FIG. 2 is a schematic diagram of a specific optical path structure of the projection system shown in FIG. 1.
  • FIG. 3 is a schematic diagram of another specific optical path structure of the projection system shown in FIG. 1.
  • FIG. 4 is a schematic diagram of a third specific optical path structure of the projection system shown in FIG. 1.
  • FIG. 5 is a software module diagram executed by the processing device of the projection system shown in FIG. 1.
  • FIG. 6 is a flowchart of a projection display method according to an embodiment of the present invention.
  • FIG. 7 is a sub-flow chart of the method shown in FIG. 6.
  • FIG. 8 is a sub-flow chart of the method shown in FIG. 7.
  • FIG. 9 is a sub-flow chart of the method shown in FIG. 6.
  • 10A-10D are schematic diagrams of light field brightness distributions presented by several different technologies.
  • FIG. 1 is a block diagram of a projection system according to a preferred embodiment of the present invention
  • FIG. 2 is a schematic diagram of a specific optical path structure of the embodiment shown in FIG.
  • the projection system 100 includes a first light source 1, a second light source 2, an optical processing component 3, a processing unit 4, an imaging system 5, and a storage unit 6.
  • the imaging system 5 further includes a spatial light modulator 51 and a projection lens 52.
  • the first light source 1 includes a plurality of illumination areas, and each illumination area can be controlled independently, so that the first light source 1 can generate a first illumination light field with a bright and dark distribution.
  • the second light source 2 generates a second illumination light field with a light and dark distribution.
  • the optical processing component 3 is configured to combine light from the first illumination light field and the second illumination light field to generate a composite light field for illuminating the spatial light modulator 51.
  • the processing unit 4 is electrically connected to the first light source 1, the second light source 2, and the spatial light modulator 51.
  • the processing unit 4 is configured to generate a first brightness distribution signal corresponding to the illumination area of the first light source 1 and a first brightness distribution signal corresponding to the second light source 2 according to a pixel gray signal of a frame of image and the maximum brightness of the first light source. Two brightness distribution signals, and output the first brightness distribution signal and the second brightness distribution signal to the first light source 1 and the second light source 2 correspondingly. Further, the processing unit 4 further compensates the image signal output to the spatial light modulator 51 according to the total brightness distribution after the first and second illumination light fields are combined to generate an image with correct grayscale and color.
  • the projection lens 52 is configured to project the image light modulated by the spatial light modulator 51 onto a projection screen.
  • the first light source 1 includes a light source array formed by a plurality of sub-light sources.
  • the light source array is arranged in an m ⁇ n array according to a length-to-width ratio of a projection screen.
  • the light source array is divided into a plurality of lighting areas. Each lighting area One or more sub-light sources can be included, and each illuminated area can be controlled independently. It can be understood that, in an implementation manner, the sub-light source is a laser, and the greater the number of sub-light sources used in the first light source 1, the more the first light source 1 can be divided into illumination areas.
  • Each lighting area in the light source array is used to emit a light beam, and the brightness of each lighting area can be independently controlled.
  • the processing unit 4 can be controlled by the processing unit 4 to be fully on, off, or emit light beams with different brightness.
  • the first light source 1 When all the illumination areas of the first light source 1 are fully on, the first light source 1 outputs uniform illumination light, and when a plurality of illumination areas emit light beams of different brightness, the first light source 1 as a whole outputs the first illumination light with a light and dark distribution. field.
  • the sub-light source of the first light source 1 may be a monochromatic laser light source, an RGB laser light source, a laser-excited phosphor light source, or a white or RGB primary color light source generated by a wavelength conversion device, or the first light source 1 may also be selected from the above-listed ones.
  • the sub-light source is a laser
  • the laser is a short-wavelength laser, such as a blue laser, which can excite the phosphor to generate primary light of different colors.
  • the second light source 2 includes a light emitting unit 21 and a light guiding element 22 disposed on a light path of the light emitting unit 21.
  • the light-emitting unit 21 is a uniform illumination light source.
  • the light-emitting unit 21 further includes a uniform light source.
  • the uniform light source is used to form a uniform light source.
  • the light-emitting unit may be a laser light source, LED light source, laser excited phosphor light source, etc.
  • the light emitted by the light emitting unit 21 is uniformly illuminated to the light guide element 22, and the light guide element 22 redistributes the illumination light field under the control of the processing unit 4 while maintaining the total light flux unchanged or slightly reduced. In the case, a light field with a light and dark distribution is produced.
  • the light guide element 22 may be a phase-modulated liquid crystal or an anamorphic mirror.
  • the light guide element 22 may be obtained by modulating the phase delay of the liquid crystal or changing the optical path difference distribution on the light guide element.
  • the light-dark distribution of the illumination light field is changed to generate a second light-dark distribution illumination light field.
  • the second light and dark distribution of the illumination light field generated by the light guide technology can increase the brightness of the bright field through the light guide element 22, thereby increasing the gradation and brightness of the bright field portion.
  • the phase modulation liquid crystal when used as the light guide element, the light emitted from the light guide element 22 generally has a polarization state due to the polarization maintaining property of the light guide element 22. Therefore, the first light source 1 and the second light source 2 having another polarization state can also be used to combine the polarization states.
  • the first light source 1 may be selected to be a laser device capable of emitting linearly polarized light in either of the polarization state A and the polarization state B
  • the light emitting unit 21 in the second light source 2 may be selected to be capable of emitting the polarization state A and polarization.
  • the polarization state of the light beam emitted from the light guide element 22 is the other of the polarization state A and the polarization state B.
  • the first light source 1 and the light guide element 22 (for example, the first light source 1) is one of polarization state A and polarization state B
  • the first The polarization state of the light beam emitted from the other one of the light source 1 and the light guide element 22 is the other one of the polarization state A and the polarization state B.
  • the polarization states A and B are orthogonal polarization states. It can be understood that the polarization state A and the polarization state B are respectively one of an s-polarization state or a p-polarization state.
  • a light combining device capable of reflecting the light in the polarization state B and transmitting the light in the polarization state A can realize a smooth light combining of the two.
  • the illumination light field generated by the first light source 1 and the illumination light field generated by the second light source 2 form a composite light field by combining polarization states.
  • the first light source 1 is a short-wavelength light source, and emits excitation light having a short-wavelength polarization state of A.
  • the light emitting unit 21 of the second light source 2 is a short-wavelength light source, which provides uniform short-wavelength illumination, and the polarization state is B.
  • the optical processing module 3 includes a relay shaping module 31, a light combining device 32 on the light exit path of the relay shaping module 31, a first light guide element 33 on the light exit path of the light guide element 22, and a light emitting path on the light exit path of the light combining device 32
  • the first relay lens group 34, the wavelength conversion device 35 on the light path of the first relay lens group 34, the light receiving relay lens group 36 on the light path of the wavelength conversion device 35, and the light receiving relay lens group A scattering element 37 on the 36 outgoing light path and a second relay lens group 38 on the main emitting light path of the scattering element 37.
  • the light combining device 32 can transmit light having a polarization state of A and reflect light having a polarization state of B.
  • the light combining device 32 can be a dichroic mirror.
  • the relay shaping component 31 is located on the exit light path of the first light source 1.
  • the relay shaping component 31 includes a light spot compression lens group 310 located on the light exit path of the first light source 1 and a light uniformity component 320 located on the light exit path of the light spot compression lens group 310.
  • the light spot compression lens group 310 is used for compressing the array light spot emitted by the first light source 1 to obtain an array light spot with a smaller area, so as to avoid overlapping between the light spots and causing uneven light emission.
  • the light spot compression lens group 310 may be an array of mirrors or an array of positive and negative lenses.
  • the light spot compression lens group 310 includes a plano-convex mirror and a plano-convex mirror located in the light emitting direction of the first light source 1, and the convex surface of the plano-convex mirror and the concave surface of the plan-convex mirror are directly opposite to each other.
  • the light homogenizing component 320 is used for homogenizing the array light spots emitted from the light spot compression lens group 310.
  • the light homogenizing component 320 includes a double-focal light homogenizing lens 322 and a condenser lens array 324 which are sequentially located on the light exit path of the spot compression lens group 310.
  • the double fly-eye uniform lens 322 includes two fly-eye lenses 326 arranged in mirror image. Each fly-eye lens 326 is arrayed by a plurality of minute lenses.
  • the micro lenses in the two fly-eye lenses 326 are disposed facing away from each other, and the plurality of micro lenses in the two fly-eye lenses 326 have the same shape and one-to-one correspondence.
  • the pitch of the two fly-eye lenses 326 is equal to the focal length of a single minute lens.
  • the discretized light spot generated by the first light source 1 can form a square light spot with a fixed pitch after passing through the double compound eye uniform lens 322.
  • the pitch, size, and shape of the light spots in the light spot array are determined by the focal length, size, and shape of a single lens of the fly-eye lens 326, so as to achieve uniform light output from the first light source 1.
  • the double fly-eye homogenizing lens 322 may also be a single-sided double-faced fly-eye lens, that is, a plurality of micro lenses are provided on two opposite surfaces of the single-lens lens.
  • Each lens in the condenser lens array 324 corresponds to each light source of the light source array in the first light source 1, and also forms an m ⁇ n array.
  • An optical axis of each lens in the condenser lens array 324 is parallel to an optical axis of a corresponding light source, and the condenser lens array 324 is used to focus a light beam incident on a surface thereof.
  • the light beam emitted from the first light source 1 is shaped by the relay shaping component 31 and then enters the light combining device 32.
  • the light beam emitted from the light guiding element 22 is guided by the first light guiding element 33 and is incident on the light combining device 32.
  • the light combining device 32 includes a first surface (not labeled) and The second surface (not labeled) opposite to the first surface, the light beam emitted by the first light source 1 is transmitted by the first surface of the light combining device 32, and the light beam emitted by the second light source 2 is reflected by the second surface of the light combining device 32.
  • the light beam with polarization state A emitted by the first light source 1 and the light beam with polarization state B emitted from the second light source 2 are combined at a light combining device 32 to form a composite illumination light field.
  • the first relay lens group 34 is composed of one or more convex lenses and / or one or more concave lenses. In this embodiment, the first relay lens group 34 is composed of three plano-convex lenses. The first relay lens group 34 is configured to relay the light spot emitted from the light combining device 32 to the wavelength conversion device 35.
  • the wavelength conversion device 35 is a transmission-type wavelength conversion device.
  • the wavelength conversion device 35 converts at least part of the light emitted from the first relay lens group 34 into a received laser light.
  • the wavelength conversion device 35 includes a substrate and a wavelength conversion layer provided on the substrate.
  • the substrate can drive the wavelength conversion layer at a high speed at a constant rate.
  • the wavelength conversion layer may include a phosphor capable of generating broad-spectrum light after being excited.
  • the wavelength conversion layer may be divided into one or more sections.
  • the plurality of sections may specifically be three sections, four sections, six sections, and the like.
  • Each section can be provided with a phosphor or a scattering powder. Different kinds of phosphors can be used to convert the incident light into visible light with different wavelengths.
  • the scattering powder can scatter the incident light.
  • the three-segment wavelength conversion layer can be used to receive blue laser light (excitation light) and output visible light of red, green, and blue in a time sequence.
  • the four-segment wavelength conversion layer can be used to receive blue laser light and output red, green, blue, and yellow visible light in a time sequence.
  • the six-segment wavelength conversion layer can be used for receiving blue laser light and outputting red, green, blue, red, green, and blue visible light in time sequence.
  • the spatial brightness distribution of the light beam emitted by each light source only changes the spatial grayscale distribution of the image light, and does not change the color gamut spatial distribution of the image light. Therefore, the intensity distribution of the three primary color spaces is maintained, and The color uniformity of the projected picture is guaranteed.
  • the wavelength conversion device 35 can be driven to perform a circular motion, so that a light spot formed on the wavelength conversion layer acts on the wavelength conversion layer along a predetermined path, and is converted into visible light of different wavelengths or scattered to subsequent light collection.
  • Relay lens group 36 can be driven to perform a circular motion, so that a light spot formed on the wavelength conversion layer acts on the wavelength conversion layer along a predetermined path, and is converted into visible light of different wavelengths or scattered to subsequent light collection.
  • the wavelength conversion device 35 is disposed behind the light combining device 32. If the wavelength conversion device 35 is arranged in front of the light path of the light combining device 32, after the light beam passes through the wavelength conversion device 35, the polarization state of the light source cannot be maintained, and because the light field distribution of the array light source must be maintained, it cannot pass through the PCS and other efficient
  • the polarizing device is polarized, and a polarizer using an absorption or reflection line has a problem of halving the efficiency. Therefore, the scheme of setting the wavelength conversion device 35 before the light path of the light combining device 32 is not suitable for laser-induced fluorescence. In the case of an array light source, only a pure laser is used as the array light source.
  • the light-receiving relay lens group 36 is disposed on the light-emitting optical path of the wavelength conversion device 35.
  • the light receiving relay lens group 36 is composed of a convex lens.
  • the light receiving relay lens group 36 is configured to collect the primary color light converted by the wavelength conversion device 35 and project the primary color light to the scattering element 37.
  • the main purpose of the scattering element 37 is to increase the angle of the incident angle, soften the edges of the incident spot to achieve uniform light, to achieve uniformity of the illumination light field, and to reduce unnaturalness at the junction of the array light sources.
  • the function of the scattering element 37 is equivalent to applying a Gaussian blur to the light spot emitted by the light receiving relay lens group 36, so that the sharp square light spots diffuse and overlap each other in a reserved area to form a uniform illumination light field.
  • the light from the diffusing element 37 is projected to the second relay lens group 38 after being uniformed.
  • the second relay lens group 38 is disposed on an optical path of the light emitted from the scattering element 37.
  • the second relay lens group 38 is composed of one or more convex lenses and / or one or more concave lenses.
  • the second relay lens group 38 is composed of two plano-convex lenses, and the convex surfaces of the two plano-convex lenses are opposite to each other.
  • the first relay lens group 34, the wavelength conversion device 35, the light receiving relay lens group 36, and the second relay lens group 38 do not change the distribution shape of the light spot projected thereon.
  • the imaging system 5 is located on the exit light path of the second relay lens group 38.
  • the imaging system further includes an optical-mechanical system 53.
  • the optical-mechanical system 53 is located on the outgoing light path of the second relay lens group 38, and the spatial light modulator 51 and the projection lens 52 are located on the outgoing light path of the optical-mechanical system 53.
  • the optical-mechanical system 53 The illumination light of the second relay lens group 38 is guided to the spatial light modulator 51, and on the other hand, the image light modulated by the spatial light modulator 51 is guided to the projection lens 52.
  • the spatial light modulator 51 may be a digital micromirror device (DMD) spatial light modulator, a reflective liquid crystal panel (Lcos) spatial light modulator, or an LCD spatial light modulator.
  • DMD digital micromirror device
  • Lcos reflective liquid crystal panel
  • the optical path structure shown in FIG. 2 is also suitable for recombining the first illumination light field and the second illumination light field by means of wavelength combining.
  • the first light source 1 and the second light source 2 are short-wavelength light sources with different wavelengths.
  • the first light source 1 selects 445 nm blue light and the second light source 2 uses 455 nm blue light.
  • the light combining device 32 has a wavelength. The device is selected to combine the first illumination light field with the second illumination light field by reflection and transmission. Wavelength combining is not limited to combining blue light.
  • the first light source 1 may also use 520 nm green laser or 635 nm red laser; and the second light source 21 may use 532 nm green laser or 655 nm red laser. In this way, the first light source 1 and the second light source 21 can also combine light. .
  • FIG. 3 is another specific optical path structure of the projection system 100.
  • the illumination light field generated by the first light source 1 and the illumination light field generated by the second light source 2 are spatially combined. A composite light field is formed.
  • the optical path structure in this embodiment is simpler.
  • the projection system 100 includes a first light source 1, a second light source 2, an optical processing component 3a, a processing unit 4 (not shown), and an imaging system 5a.
  • the first light source 1 is Array light source including multiple illuminated areas.
  • the second light source 2 includes a light emitting unit 21 and a light guiding element 22.
  • the optical processing module 3 a includes a relay shaping module 31 located on the light path of the first light source 1 and a first relay lens group 34 located on the light path of the relay shaping module 31.
  • the relay shaping component 31 includes a light spot compression lens group 310 and a uniform light component 320.
  • the imaging system 5a includes a spatial light modulator 51a, a projection lens 52a, and an optical-mechanical system 53a.
  • the optical-mechanical system 53a includes a total internal reflection prism (TIR) and is located in the first relay lens group 34 Out of light.
  • TIR total internal reflection prism
  • the omitted processing unit 4 is still electrically connected to the first light source 1, the second light source 2, and the spatial light modulator 51a.
  • the first light source 1 and the second light source 2 both use laser light as the light source and have a small expansion amount, so that the cone angle irradiated onto the spatial light modulator 51a can be controlled to be small.
  • the first light source 1 and the second light source 2 can be The cone angle is less than half of the deflection angle of the micromirror array and half of the light receiving angle of the projection lens 52a, so that the first light source 1 and the second light source 2 can illuminate the spatial light modulator 51a at different angles and can be collected by the projection lens 52a To achieve imaging.
  • the light beam emitted from the first light source 1 is shaped by a relay shaping component 31 to obtain a directional light spot with a fixed pitch.
  • the square light spot passes through the first relay lens group 34 and is projected to a total internal reflection prism.
  • the light beam emitted by the second light source 2 is at an acute angle with the light beam emitted by the first light source 1. Therefore, both the light beam emitted by the second light source 2 and the light beam emitted by the first light source 1 can reach the total internal reflection prism, and after being reflected by the total internal reflection prism, reach the spatial light modulator 51a.
  • the spatial light modulator 51a modulates the incident light, the modulated image light is transmitted through the total internal reflection prism, and finally is projected on a screen through the projection lens 52a.
  • FIG. 4 is a schematic diagram of a third specific optical path structure of the projection system 100.
  • the optical path structure of the projection system 100 is basically the same as the optical path structure shown in FIG. 2, that is, the projection system 100 includes the first light source 1. , Second light source 2, optical processing module 3b, processing unit 4 and imaging system 5.
  • the optical processing module 3b includes a relay shaping module 31, a light combining device 32 on the light path of the relay shaping module 31, a first light guide element 33 on the light path of the light guiding element 22, and a light combining device 32.
  • a first relay lens group 34, a wavelength conversion device 350, a light-receiving relay lens group 36, a scattering element 37, and a second relay lens group 38 are provided in this order in the outgoing light path.
  • the imaging system 5 includes a spatial light modulator 51, a projection lens 52a, and an optical-mechanical system 53.
  • the projection system 100 differs from that shown in FIG. 2 in that the wavelength conversion device 350 in this embodiment is a reflective wavelength conversion device, and the projection system 100 further includes a second light guide element 43 and a first light guide element 43.
  • Three relay lens group 45 is provided in that shown in FIG. 2 in that the wavelength conversion device 350 in this embodiment is a reflective wavelength conversion device, and the projection system 100 further includes a second light guide element 43 and a first light guide element 43.
  • the third relay lens group 45 is disposed opposite to the first relay lens group 34.
  • the second light guide element 43 is provided on the optical path between the first relay lens group 34 and the third relay lens group 45.
  • the third relay lens group 45 is composed of one or more convex lenses and / or one or more concave lenses.
  • the illumination light field spot combined by the light combining device 32 passes through the third relay lens group 45, the second light guide element 43, and the third relay lens group 45, and enters the wavelength conversion device 350.
  • the light beam emitted from the wavelength conversion device 350 passes through the third relay lens group 45 and is then reflected by the second light guide element 43 to be received by the light receiving relay lens group 36.
  • the optical path after passing through the light-receiving relay lens group 36 is the same as that shown in FIG. 2, and is not repeated here.
  • FIG. 5 shows software modules that the processing unit 4 needs to execute when the projection system 100 is running to generate control of the first light source 1, the second light source 2, and the spatial light modulators 51 and 51 a. Control signal.
  • the software module is stored in the storage unit 6 and is called by the processing unit 4.
  • the software module includes a first light source brightness control module 401 and a second light source brightness control module 402, wherein the first light source brightness control module 401 is configured to at least according to a pixel gray signal of an image frame to be projected and a maximum brightness of the first light source 1.
  • a brightness distribution signal (hereinafter referred to as a "first light source brightness distribution signal”) corresponding to the illumination region of the first light source 1 is generated, and the first light source brightness distribution signal is output to the illumination region of the first light source 1 to generate a first illumination light field.
  • the first light source brightness control module 401 generates a brightness distribution signal (hereinafter referred to as an "image brightness distribution signal”) corresponding to the grayscale signal of the pixel of the image frame to be projected and the maximum brightness of the first light source 1.
  • the first light source brightness distribution signal is generated, and the first light source brightness distribution signal is output to the illumination region of the first light source 1 to generate a first illumination light field.
  • the first light source brightness control module 401 generates a brightness distribution signal (hereinafter referred to as an "image brightness distribution signal”) corresponding to the grayscale signal of the pixel of the image frame to be projected and the maximum brightness of the first light source 1.
  • the second light source brightness control module 402 is configured to generate a brightness distribution signal for controlling the light guide element 22 (hereinafter referred to as a "second light source brightness distribution signal") according to the pixel grayscale signal of the image frame and the first light source brightness distribution signal.
  • the control light guide element 22 generates a second illumination light field.
  • the first illumination light field and the second illumination light field are combined at the light combining device 32 to form a composite light field.
  • the second light source brightness control module 402 calculates the remaining illumination light distribution according to the difference between the image brightness distribution signal and the first light source brightness distribution signal, and then generates a second light source brightness distribution signal according to the remaining illumination light distribution.
  • the software module further includes an electro-optical conversion module 403.
  • the electro-optical conversion module 403 is configured to convert a pixel grayscale signal of the image frame into an image brightness distribution signal, and the image brightness distribution signal is sent to a first light source brightness.
  • the control module 401 and the second brightness control module 402 enable the first light source brightness control module 401 and the second brightness control module 402 to generate a first light source brightness distribution signal and a second light source brightness distribution signal, respectively.
  • the electro-optical conversion module 403 implements the above functions according to an electro-optical conversion function (EOTF).
  • EOTF electro-optical conversion function
  • the electro-optical conversion function is generated according to the characteristics of post-production and image signals, such as a PQ function, an HLG function, and a conversion function dynamically generated according to image content.
  • the software module further includes a composite illumination light distribution calculation module 404 and a compensated pixel grayscale module 405.
  • the composite illumination light distribution calculation module 404 is configured to calculate a composite brightness distribution signal (hereinafter referred to as a "total brightness distribution signal") according to the first light source brightness distribution signal and the second light source brightness distribution signal.
  • the compensation pixel grayscale module 405 is configured to compensate the pixel grayscale signal of the image frame to generate and output the image signal to the spatial light modulators 51 and 51a according to the difference between the image brightness distribution signal and the total brightness distribution signal.
  • the brightness of the light emitting unit 21 of the second light source 2 can be set to be adjustable or non-adjustable.
  • the processing unit 4 may further adjust the brightness of the light emitting unit 21 according to the brightness requirement of the image frame to be projected.
  • the process may specifically be: the second light source brightness control module generates a brightness control signal corresponding to the light emitting unit 21 according to the second light source brightness distribution signal, so as to adjust the brightness of the light emitting unit 21 according to the brightness required by the light guide element 22.
  • the first light source brightness control module 401 determines a light guide element according to a pixel gray signal of the image frame (specifically, according to an image brightness distribution signal) and a maximum brightness of the first light source.
  • the first light source brightness control module 401 generates a pre-brightness distribution signal according to the pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal) and the maximum brightness of the first light source, and then calculates the pre-brightness distribution. The difference between the signal and the retained brightness in the light reduction region of the light guide element 22 is used to obtain the first light source brightness distribution signal.
  • the second light source brightness control module 402 may also The pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal) and the first light source brightness distribution signal determine the light reduction area and the light increase area of the light guide element 22, and calculate the required increase in the light increase area.
  • the brightness and the brightness distribution of the light reduction area are calculated according to the light energy output by the light emitting unit 21 and the brightness required to increase in the light increase area, so as to obtain a second light source brightness distribution signal.
  • the second light source brightness control module 402 divides the remaining light energy after satisfying the required increased brightness of the light increasing area to each unit area of the light reducing area.
  • FIG. 6 is a method flowchart of a projection display method according to an embodiment of the present invention.
  • the method can be used in the projection system 100 described above.
  • the projection display method is described below with reference to the projection system 100.
  • the method is specific The steps involved are as follows.
  • Step S601 the first light source brightness control module 401 generates a first light source brightness distribution signal according to at least a pixel grayscale signal of an image frame to be projected (specifically, according to the image brightness distribution signal) and the maximum brightness of the first light source 1, and
  • the first light source brightness distribution signal is output to a plurality of illumination areas of the first light source 1 to generate a first illumination light field.
  • Step S602 the second light source brightness control module 402 generates a second light source brightness that controls the light guide element 22 according to the pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal) and the first light source brightness distribution signal.
  • the signal is distributed to control the light directing element 22 to generate a second illumination light field.
  • the light combining device 32 combines the first illumination light field and the second illumination light field to generate a composite light field.
  • the light combining mode may be polarization combining light, wavelength combining light, or spatial angle combining light.
  • step S604 the composite light field is continuously guided to the spatial light modulators 51 and 51a through the optical processing components 3 and 3a, and the spatial light modulators 51 and 51a are illuminated with the composite light field so that the spatial light modulators 51 and 51a correspond to Under the control of the image signal of the image frame, an image light carrying image information is output.
  • the optical processing components 3 and 3a may further include processing such as wavelength conversion of the composite light field.
  • step S602 may further include: the second light source brightness control module 402 calculates the remaining illumination light distribution according to the difference between the image brightness distribution signal and the first light source brightness distribution signal, and generates and controls the light guide element according to the remaining illumination light distribution.
  • the second light source brightness distribution signal may further include: the second light source brightness control module 402 calculates the remaining illumination light distribution according to the difference between the image brightness distribution signal and the first light source brightness distribution signal, and generates and controls the light guide element according to the remaining illumination light distribution.
  • the second light source brightness distribution signal may further include: the second light source brightness control module 402 calculates the remaining illumination light distribution according to the difference between the image brightness distribution signal and the first light source brightness distribution signal, and generates and controls the light guide element according to the remaining illumination light distribution. The second light source brightness distribution signal.
  • step S601 the method may further include step S600: the electro-optical conversion module 403 converts the pixel grayscale signal of the image frame into an image brightness distribution signal.
  • the method may further include the steps: step S605, the composite illumination light distribution calculation module 404 calculates a total brightness distribution signal according to the first light source brightness distribution signal and the second light source brightness distribution signal; and step S606, the compensation pixel grayscale module 405 Compensating the pixel grayscale signal of the image frame to generate the image signal and outputting the image signal to the spatial light modulation according to the brightness distribution signal and the total brightness distribution signal of the pixel grayscale signal corresponding to the image frame ⁇ 51,51a.
  • the method may further include the step of: the second light source brightness control module generates a brightness control signal corresponding to the light emitting unit 21 according to the second light source brightness distribution signal, so as to The required brightness adjusts the brightness of the light emitting unit 21.
  • step S601 may further include the following steps, please refer to FIG. 7.
  • step S701 the first light source brightness control module 401 determines the light reduction area and light of the light guide element 22 according to the pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal) and the maximum brightness of the first light source. Increase area.
  • Step S702 The first light source brightness control module 401 is based on the pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal), the maximum brightness of the first light source, and the light reduction area of the light guide element 22. The retained brightness generates a first light source brightness distribution signal.
  • step S702 can further include the following steps, please refer to FIG. 8.
  • step S801 the first light source brightness control module 401 generates a pre-brightness distribution signal according to the pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal) and the maximum brightness of the first light source.
  • step S802 the first light source brightness control module 401 calculates the difference between the front brightness distribution signal and the remaining brightness in the light reduction area of the light guide element 22 to obtain the first light source brightness distribution signal.
  • step S602 may further include the following steps, please refer to FIG. 9.
  • Step S901 the second light source brightness control module 402 determines the light reduction area and light of the light guide element 22 according to the pixel grayscale signal of the image frame (specifically, according to the image brightness distribution signal) and the first light source brightness distribution signal. Increase area.
  • step S902 the second light source brightness control module 402 calculates the brightness required to be increased in the light increasing area.
  • step S903 the second light source brightness control module 402 calculates the brightness distribution of the light-reduced area according to the light energy output by the light emitting unit 21 and the required brightness of the light-increased area, thereby obtaining the first light source brightness distribution signal.
  • step S903 may further include: dividing the remaining light energy after satisfying the required increased brightness of the light increasing area to each unit area of the light reducing area.
  • the processing unit 4 receives a pixel grayscale signal of an image to be projected, and divides the image corresponding to the partition of the illumination area of the first light source 1 to obtain a plurality of image partitions.
  • the processing unit 4 calculates the brightness of each image partition and generates a control signal of the first light source 1 and the second light source 2 corresponding to each image partition.
  • the processing unit 4 controls the first light source 1 according to the control signal, so that the first light source 1 achieves the effect of locally dimming the area illumination according to the image to be projected.
  • the processing unit 4 controls the light-guiding element 22 of the second light source 2 to perform phase modulation or change the optical path difference to obtain a light distribution field with bright and dark distribution.
  • the processing unit 4 generates a compensation control signal according to the brightness distribution of the illumination light source after the first light source 1 and the second light source 2 are combined and the pixel gray signal of the image to be projected.
  • the spatial light modulators 51 and 51a modulate the brightness corresponding to the light beams emitted by the first light source 1 and the second light source 2 according to the compensated control signal to obtain image light, and further project a display screen through the projection lens 52.
  • the present invention can greatly increase the peak brightness of the branch where the light guide element 22 is located by using local illumination local dimming and light guiding technology, and then superimposing a uniform light field to greatly increase the peak brightness of the picture. And the average brightness of the picture is increased by the uniform illumination branch of the first light source 1.
  • FIGS. 10A-10D are schematic diagrams of the light field brightness distribution that can be presented by the local lighting local dimming and light guiding technology respectively and in combination.
  • FIG. 10A shows the brightness distribution that can be achieved by light field modulation using local illumination local dimming technology.
  • the reference numeral 1001 represents the maximum brightness that the projection system 100 can achieve when displaying a uniform color picture.
  • Reference numeral 1002 is a proportion of darkening of each region.
  • Reference numeral 1003 is a brightness distribution of each region after dimming. It can be seen that the technology of local dimming of area lighting cannot break through the brightness in the uniform white field, and the peak brightness of the picture is equal to the maximum brightness in the white field. Through local dimming, only the light leakage in the dark field of the picture can be reduced, thereby reducing the brightness of the black area and achieving the purpose of increasing the contrast.
  • FIG. 10B is a schematic diagram showing the brightness distribution of the light guiding technology.
  • the reference numeral 1004 indicates the maximum brightness when the projection system 100 displays a uniform white field when the light guiding technology is used alone. Since the light guiding technology can control the spatial brightness distribution of the output light field, the illumination light in the dark field in the picture can be directed to the bright field portion. Therefore, the peak brightness that can be achieved by the light guiding technology is much larger than that when displaying a uniform white field, as shown by reference numeral 1006.
  • Reference numeral 1005 indicates the remaining brightness in other regions. However, the light guiding technology cannot increase the total number of lumens output by the projection system 100, that is, the total number of lumens of the picture is constant.
  • the darker the dark field in the picture and the smaller the proportion of the bright field the higher the peak brightness and the higher the contrast.
  • the light guiding technology has to divide most of the lumens to illuminate the middle gray and dark areas, so that the number of lumens that can be used for peak brightness pixels is insufficient.
  • the maximum brightness (peak brightness) of the light guide technology in general application scenarios is limited.
  • a uniform light supplement light field 1007 is added based on the light guide technology, as shown in FIG. 10C.
  • the brightness of the medium gray and dark pixels in the picture is mainly provided by the uniform fill light field.
  • the light guide device can focus most of the light that can be controlled and controlled near the peak brightness pixels, so that it can be displayed in most scenes. High peak brightness.
  • the illumination light of the black field in the picture is greatly increased, thereby increasing the light leakage during the black field, increasing the brightness of the black pixels in the picture, and reducing the contrast that the picture can achieve from one aspect.
  • FIG. 10D is a schematic diagram of the spatial distribution of the brightness after the combination of the light guiding technology and the local dimming technology of the area lighting according to the embodiment of the present invention, that is, the technical effect of the superposition of FIG. 10A and FIG. 10B.
  • the picture first uses the local dimming technology to produce a low-frequency illumination light field to ensure the lighting of medium-gray and low-brightness pixels in the picture. Then, for pixels that exceed the maximum brightness of the local dimming light source, the light field is allocated by the light guide technology to supplement the light.
  • the purpose of reducing the brightness of the black field and increasing the brightness of the peak can achieve better results than using these two technologies alone.
  • the projection system uses two illumination light sources to generate first and second two illumination light fields.
  • the first illumination light field uses area illumination local dimming technology to generate light and dark distribution according to the content of the screen.
  • the background illumination light; the second illumination light field uses light-guided technology to generate another light distribution of dark and light distribution.
  • the first and second illumination light are combined in front of the spatial light modulator to form a composite illumination light field to illuminate the spatial light modulator.
  • the purpose is to simultaneously increase the peak brightness of the picture and reduce the brightness of the black field of the picture, thereby increasing the order of the projection system and the contrast of the frame, so as to realize the function of high brightness and high dynamic range images.

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Abstract

一种投影系统包括为阵列光源的第一光源，第一光源被分成多个照明区域，每一照明区域可被独立控制以产生明暗可调制的第一照明光场；第二光源包括发光单元与光导向元件；光导向元件将发光单元发出的照明光重新分布以产生明暗可调制的第二照明光场，第一、第二照明光场叠加产生一复合光场。本发明还提供一种投影显示方法。利用本发明，能同时增加画面峰值亮度和降低画面黑场亮度的目的，以获得具高对比度的投影系统。

Description

投影系统及投影显示方法 技术领域
本发明涉及光学成像技术领域，尤其涉及一种投影系统及投影显示方法。
背景技术
高动态范围(HDR)投影系统能够增加投影机输出的对比度和峰值亮度，使得画面中的亮场和暗场部分都能显示丰富的灰阶信息从而大大提高画面的效果和观众的观影体验。现有的投影系统实现高动态范围的第一种方式是利用双空间光调制器串联来对光源所发出的光进行控制而实现高动态范围显示效果，然目前采用两片空间光调制器的HDR投影系统由于新增了一片空间光调制器普遍存在光效偏低的问题，其光效约为普通投影系统的36％，较低的光效使得投影系统在实现更高的峰值亮度方面变得困难。另一种方式是采用两个投影系统，一个显示标准对比度画面，另一个显示高亮度成分用于增亮高光部的亮度以实现高峰值亮度的显示，然而，画面中所能达到的最小黑场亮度受限于产生标准对比度画面的投影机，从而使得使用该技术的投影系统黑场的亮度仍然很高，从而减小了对比度以及观影体检。
发明内容
有鉴于此，本发明提供一种能克服上述问题的投影系统与投影显示方法。
一方面，提供一种投影系统，包括：
第一光源，所述第一光源为一阵列光源，所述第一光源被分成多个照明区域，每一照明区域可被独立控制以使所述第一光源产生明暗可调制的第一照明光场；
第二光源，所述第二光源包括发光单元与光导向元件；所述光导向元件用以将发光单元发出的照明光重新分布以产生明暗可调制的第二照明光场，所述第二照明光场与第一照明光场叠加产生一复合光场；
处理单元，执行软件模块包括：
第一光源亮度控制模块，用于至少根据待投影图像帧的像素灰度信号与所述第一光源最大亮度生成对应所述第一光源照明区域的亮度分布 信号，并输出所述亮度分布信号至所述第一光源的照明区域以产生所述第一照明光场；及
第二光源亮度控制模块，用于根据所述图像帧的像素灰度信号以及对应所述第一光源照明区域的亮度分布信号，生成控制所述光导向元件的亮度分布信号，以控制所述光导向元件生成所述第二照明光场；及空间光调制器，所述空间光调制器用于根据所述处理单元输出的图像信号调制所述复合光场，以产生携带图像信息的图像光。
另一方面，提供一种投影显示方法，包括：
至少根据待投影图像帧的像素灰度信号以及一第一光源的最大亮度生成对应所述第一光源多个照明区域的亮度分布信号，并输出所述亮度分布信号至所述第一光源的多个照明区域以生成一第一照明光场；
根据所述图像帧的像素灰度信号以及对应所述第一光源多个照明区域的亮度分布信号，生成控制一光导向元件的亮度分布信号，以控制所述光导向元件生成一第二照明光场；
复合所述第一照明光场与第二照明光场以生成一复合光场；
利用所述复合光场照明一空间光调制器，以使所述空间光调制器在对应所述图像帧的图像信号的控制下，输出携带图像信息的图像光。
与现有技术相比较，本发明提供的投影系统及投影显示方法，由于第一光源能产生第一照明光场，第一照明光场由于包括阵列排布的光源，第一光源每个照明区域能够独立控制器其亮度，从而能根据画面内容产生明暗分布且可调的第一照明光场，第一照明光场能根据需要减暗画面中的暗场部分的亮度，从而增加投影系统的对比度；第二光源通过光导向技术也能产生明暗分布且可调的第二照明光场，光导向技术能增加画面亮场的亮度，以此来增加亮场部分的色阶和亮度。第一照明光场和第二照明光场在空间光调制器前合光后形成复合照明光场照明空间光调制器，从而达到同时增加画面峰值亮度和降低画面黑场亮度的目的，以获得具高对比度的投影系统。
附图说明
图1是本发明一较佳实施方式的投影系统的方框示意图。
图2是图1所示投影系统的一种具体光路结构示意图。
图3是图1所示投影系统的另一种具体光路结构示意图。
图4是图1所示投影系统的第三种具体光路结构示意图。
图5是图1所示投影系统的处理装置执行的软件模块图。
图6是本发明一实施方式中的投影显示方法流程图。
图7是图6所示方法的子流程图。
图8是图7所示方法的子流程图。
图9是图6所示方法的子流程图。
图10A-10D是几种不同技术呈现的光场亮度分布示意图。
如下具体实施方式将结合上述附图进一步说明本发明。
具体实施方式
为了能够更清楚地理解本发明的上述目的、特征和优点，下面结合附图和具体实施方式对本发明进行详细描述。需要说明的是，在不冲突的情况下，本申请的实施方式及实施方式中的特征可以相互组合。
在下面的描述中阐述了很多具体细节以便于充分理解本发明，所描述的实施方式仅是本发明一部分实施方式，而不是全部的实施方式。基于本发明中的实施方式，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施方式，都属于本发明保护的范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文中在本发明的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是旨在于限制本发明。
请参阅图1-2，图1是本发明一较佳实施方式的投影系统的方框示意图，图2是图1所示实施方式的一种具体光路结构示意图。所述投影系统100包括第一光源1、第二光源2、光学处理组件3、处理单元4、成像系统5及存储单元6。其中成像系统5进一步包括空间光调制器51及投影镜头52。
所述第一光源1包括多个照明区域，每一照明区域能被独立控制，从而使第一光源1能产生明暗分布的第一照明光场。所述第二光源2产生明暗分布的第二照明光场。所述光学处理组件3用于第一照明光场与第二照明光场进行合光以产生一照明空间光调制器51的复合光场。所述处理单元4与所述第一光源1、所述第二光源2及所述空间光调制器51电性连接。所述处理单元4用以根据一帧图像的像素灰度信号以及所述第一光源的最大亮度生成对应所述第一光源1的照明区域的第一亮度分布信号与对应第二光源2的第二 亮度分布信号，并将第一亮度分布信号与第二亮度分布信号对应输出至第一光源1与第二光源2。进一步地，所述处理单元4还根据第一及第二照明光场复合后总的亮度分布来补偿输出给空间光调制器51的图像信号以产生正确灰阶和色彩的图像。所述投影镜头52用于将所述空间光调制器51调制的图像光投射到投影屏幕上。
具体地，请参阅图2中所述投影系统100的具体光路结构。
所述第一光源1包括由多个子光源形成的光源阵列，所述光源阵列按照投影画面的长宽比例排列成m×n的阵列，所述光源阵列被分成多个照明区域，每一照明区域可包括一或多个子光源，每一照明区域可被独立控制。可以理解，在一种实施方式中，所述子光源为激光器，第一光源1中采用的子光源的数目越多，第一光源1就能被分为越多的照明区域。所述光源阵列中每个照明区域用于发出光束且每个照明区域的亮度是可被独立控制的，譬如可以通过处理单元4控制为全开状态、关闭状态、或者发出具有不同亮度的光束，当第一光源1的所有照明区域均为全开状态时，第一光源1输出均匀照明光，当多个照明区域发出不同亮度的光束时，第一光源1整体输出明暗分布的第一照明光场。
所述第一光源1的子光源可以是单色激光光源、RGB激光光源、激光激发荧光粉光源或波长转换装置产生的白光或RGB基色光光源，或者，第一光源1也可以由上述列举的几种光源中的一种或者多种进行合适的组合的结果。在本实施方式中，所述子光源为激光器，激光器为能够激发荧光粉产生不同颜色的基色光的短波长激光，如蓝光激光器。
所述第二光源2包括发光单元21及设置在所述发光单元21出光光路上的光导向元件(Light steering)22。在一种实施方式中，所述发光单元21为均匀照明光源，例如，所述发光单元21还包括一匀光装置，利用匀光装置形成均匀的照明光源，所述发光单元可以为激光光源、LED光源、激光激发荧光粉光源等。所述发光单元21发出的光均匀化照明到光导向元件22上，所述光导向元件22在所述处理单元4的控制下重新分布照明光场，在保持总的光通量不变或微量减少的情况下产生明暗分布的照明光场。所述光导向元件22可以为相位调制液晶或变形镜等，当光导向元件22为相位调制液晶或变形镜时，其可通过调制液晶的相位延迟或改变光导向元件上的光程差分布来改变照明光场的明暗分布，从而产生第二明暗分布的照明光场。利用光导向 技术产生的第二明暗分布的照明光场能通过光导向元件22来增加亮场的亮度，以此来增加亮场部分的色阶和亮度。
可以理解，当光导向元件采用相位调制液晶时，由于光导向元件22的保偏性，从光导向元件22出射的光一般具有偏振态。因此，亦可采用具有另一偏振态的第一光源1与第二光源2进行偏振态合光。
例如，可以选择第一光源1是能发出偏振态A和偏振态B中的任何一种的线偏振光的激光装置，而选择第二光源2中的发光单元21是能发出偏振态A和偏振态B中另一种的激光装置，光导向元件22出射的光束的偏振态则为偏振态A与偏振态B中另一种。也就是说，当所述第一光源1及光导向元件22中的一个(例如第一光源1)出射的光束的偏振态为偏振态A和偏振态B中的一种时，所述第一光源1及光导向元件22中的另外一个(例如光导向元件22)出射的光束的偏振态为偏振态A和偏振态B中的另外一种。偏振态A和偏振态B为正交偏振态。可以理解，偏振态A和偏振态B分别为s偏振态或者p偏振态中的一种。利用能够反射偏振态B的光而透射偏振态A的光的合光器件就能实现两者的顺利合光。
请参阅图2所示，在图2所示具体实施中，第一光源1产生的照明光场与第二光源2产生的照明光场采用偏振态合光的方式形成复合光场。
第一光源1为短波长光源，出射短波长偏振态为A的激发光。第二光源2的发光单元21为短波长光源，提供均匀的短波长照明，偏振态为B。光学处理组件3包括中继整形组件31、位于中继整形组件31出射光路上的合光装置32、位于光导向元件22出射光路上的第一光引导元件33、位于合光装置32出射光路上的第一中继透镜组34、位于第一中继透镜组34出射光路上的波长转换装置35、位于波长转换装置35出射光路上的收光中继透镜组36、位于收光中继透镜组36出射光路上的散射元件37、及位于散射元件37主要出射光路上的第二中继透镜组38。
在本实施方式中，所述合光装置32能透射偏振态为A的光而反射偏振态为B的光，所述合光装置32可以为一二向色镜。
在本实施方式中，中继整形组件31位于第一光源1的出射光路上。所述中继整形组件31包括位于第一光源1出射光路上的光斑压缩透镜组310以及位于光斑压缩透镜组310出射光路上的匀光组件320。
光斑压缩透镜组310用于对第一光源1发出的阵列光斑进行压缩以获得 面积更小的阵列光斑，避免光斑之间出现交叠导致出光不均匀。光斑压缩透镜组310可以是反射镜组成的阵列，也可以是正负透镜组成的阵列。在本实施方式中，光斑压缩透镜组310包括位于第一光源1出光方向上的一个平凸镜以及一个平凹凸镜，平凸镜的凸面与平凹凸镜的凹面正对设置。
匀光组件320用于对光斑压缩透镜组310发出的阵列光斑进行匀光。在本实施方式中，匀光组件320包括依次位于光斑压缩透镜组310出射光路上的双复眼匀光透镜322以及聚光透镜阵列324。双复眼匀光透镜322包括两个镜像设置的复眼透镜326。每个复眼透镜326由多个微小透镜形成阵列排列。两个复眼透镜326中的微小透镜背离彼此方向设置，且两个复眼透镜326中的多个微小透镜形状相同、一一对应。两个复眼透镜326的间距等于单个微小透镜的焦距。
可以理解，所述第一光源1产生的离散化的光斑经过所述双复眼匀光透镜322能形成具固定间距的方形光斑。光斑阵列中的光斑的间距、尺寸大小、形状由复眼透镜326的单个透镜焦距、大小和形状决定，如此来实现第一光源1的出光均匀化。
当然，在其他实施方式中，所述双复眼匀光透镜322还可以是单片双面的复眼透镜，即在单片透镜的相背的两个表面设置多个微小透镜。
所述聚光透镜阵列324中的每个透镜与第一光源1中的光源阵列的每个光源一一对应，也形成m×n的阵列。所述聚光透镜阵列324中的每个透镜的光轴与对应光源的光轴平行，所述聚光透镜阵列324用于将入射其表面的光束进行聚焦。
在本实施方式中，第一光源1出射的光束经过中继整形组件31整形后入射至合光装置32。从光导向元件22出射的光束经过第一光引导元件33的引导后入射至合光装置32，具体地，在本实施方式中，所述合光装置32包括第一面(未标示)及与第一面相背的第二面(未标示)，第一光源1出射的光束由合光装置32的第一面透射，第二光源2出射的光束由合光装置32的第二面反射，由此第一光源1出射的偏振态为A的光束与第二光源2出射的偏振态为B的光束在合光装置32处合光形成一复合的照明光场。
第一中继透镜组34由一个或多个凸透镜及/或一个或多个凹透镜组成。在本实施方式中，第一中继透镜组34由三个平凸透镜组成，第一中继透镜组34用于将自所述合光装置32出射的光斑中继至波长转换装置35上。
在本实施方式中，波长转换装置35为透射式波长转换装置。波长转换装置35将至少部分第一中继透镜组34出射的光转换成受激光。波长转换装置35包含基板和设置于基板上的波长转换层，基板能以恒定速率带动波长转换层高速转动。所述波长转换层可以包括受激发后能够产生宽谱光的荧光粉。
其中，所述波长转换层可分为一个或多个区段。所述多个区段具体可为三区段、四区段、六区段等。每个区段可设置一种荧光粉或散射粉，不同种的荧光粉可用于将入射光转换成不同波长的可见光，散射粉可将入射光散射。例如，所述三区段的波长转换层可用于接收蓝色激光(激发光)并按时序输出红色、绿色、及蓝色的可见光。所述四区段的波长转换层可用于接收蓝色激光并按时序输出红色、绿色、蓝色、及黄色的可见光。所述六区段的波长转换层可用于接收蓝色激光并按时序输出红色、绿色、蓝色、红色、绿色、及蓝色的可见光。
在本实施方式中，每个光源所发出的光束的空间亮度分布只改变图像光的空间灰阶分布，而不改变图像光的色域空间分布，因此保证了三原色空间的强度分布不变，从而保证了投影画面颜色的均匀性。所述波长转换装置35可以被驱动而做圆周运动，从而光束在波长转换层上形成的光斑沿着预定路径作用于波长转换层，而被转换为不同波长的可见光或被散射至后续的收光中继透镜组36。
在图2所示实施方式中，将波长转换装置35设置在合光装置32之后。若将波长转换装置35设置在所述合光装置32的光路之前，光束经过波长转换装置35后，光源的偏振态不能被保持，且由于要保持阵列光源的光场分布，无法通过PCS等高效的起偏器件起偏，而用吸收或反射行的起偏器会存在效率减半的问题，因此，将波长转换装置35设置在所述合光装置32的光路之前的方案不适合激光激发荧光作为阵列光源的情况，仅适用于纯激光作为阵列光源。
所述收光中继透镜组36设置在所述波长转换装置35的出光光路上。在本实施方式中，所述收光中继透镜组36由一个凸透镜组成。所述收光中继透镜组36用于收集通过所述波长转换装置35转换后的基色光并投射至所述散射元件37。
所述散射元件37的主要目的是能增大入射角的角度，柔化入射光斑的边缘，以实现匀光，以实现照明光场的均匀性以及减少阵列光源交界处的不自 然。所述散射元件37的作用是相当于对收光中继透镜组36出射的光斑施加了一个高斯模糊，使得边缘锐利的方形光斑产生扩散并在预留区域相互叠加以形成均匀照明光场，经过所述散射元件37的匀光后再投射至所述第二中继透镜组38。
所述第二中继透镜组38设置在所述散射元件37的出光光路上。所述第二中继透镜组38由一个或多个凸透镜及/或一个或多个凹透镜组成。在本实施方式中，所述第二中继透镜组38由两个平凸镜组成，两个平凸镜的凸面相背对设置。所述第一中继透镜组34、所述波长转换装置35、所述收光中继透镜组36及所述第二中继透镜组38皆不改变投射在其上的光斑的分布形状。
成像系统5位于第二中继透镜组38的出射光路上，除空间光调制器51与投影镜头52外，在本实施方式中，成像系统还包括光机系统53。光机系统53位于第二中继透镜组38的出射光路上，空间光调制器51与投影透镜52位于光机系统53的出射光路上，在本实施方式中，光机系统53一方面将来自第二中继透镜组38的照明光引导至空间光调制器51上，另一方面，将空间光调制器51调制的图像光引导至投影透镜52。可以理解，所述空间光调制器51可以为数字微镜装置(DMD)空间光调制器、反射式液晶面板(Lcos)空间光调制器或LCD空间光调制器等。
图2所示光路结构同样适用于通过波长合光的方式将第一照明光场与第二照明光场进行复合。通过波长合光时，第一光源1和第二光源2为不同波长的短波长光源，例如，第一光源1选择445nm的蓝光而第二光源2采用455nm的蓝光，合光装置32为一波长选择器件，通过反射和透射来将第一照明光场与第二照明光场复合。波长合光亦不限于蓝光的合光。比如第一光源1还可以采用520nm的绿激光或者635nm的红激光；而第二光源21可以采用532nm的绿激光或者655nm的红激光，如此，第一光源1和第二光源21也可以合光。
请参阅图3所示，为投影系统100另一种具体光路结构，在本具体实施方式中，第一光源1产生的照明光场与第二光源2产生的照明光场采用空间合光的方式形成复合光场。与图2所示通过偏振态合光的方式相比，本具体实施方式中光路结构更加简单。具体地，在本实施方式中，所述投影系统100包括第一光源1、第二光源2、光学处理组件3a、处理单元4(图未示)、及成像系统5a，其中第一光源1为阵列光源，包括多个照明区域。第二光源2 包括发光单元21与光导向元件22。光学处理组件3a包括位于第一光源1出光光路上的中继整形组件31及位于中继整形组件31出光光路上的第一中继透镜组34。中继整形组件31包括光斑压缩透镜组310及匀光组件320。成像系统5a包括空间光调制器51a、投影镜头52a及光机系统53a，在本实施方式中，光机系统53a包括全内反射棱镜(Total Internal Reflection，TIR)，位于第一中继透镜组34出光光路上。省略的处理单元4仍然与所述第一光源1、第二光源2及空间光调制器51a电性连接。
第一光源1与第二光源2均采用激光作为光源，具有很小的扩展量，因而照射到空间光调制器51a上的锥角可以控制得很小。在本实施方式中，通过选择偏转较大的微镜阵列DMD作为空间光调制器51a再配合较小光圈值(F-number)的投影镜头52a，能够使得第一光源1与第二光源2的锥角小于微镜阵列偏转角的一半及投影镜头52a收光角度的一半，从而使得第一光源1与第二光源2能够以不同的角度照射空间光调制器51a且能够被投影镜头52a所收集，从而实现成像。
具体地，第一光源1发出的光束，经过中继整形组件31整形后得到具固定间距的方向光斑。所述方形光斑经过第一中继透镜组34后投射至全内反射棱镜。第二光源2发出的光束与第一光源1发出的光束呈一锐角。从而，第二光源2发出的光束与第一光源1发出的光束均能到达全内反射棱镜，经全内反射棱镜反射后到达空间光调制器51a。在处理单元4的控制下，空间光调制器51a对入射光进行调制，调制后的图像光经全内反射棱镜透射后，最终通过投影镜头52a投影至一荧幕上。
请参阅图4，图4为投影系统100的第三具体光路结构示意图，本实施方式中，投影系统100的光路结构与图2所示的光路结构基本相同，即投影系统100包括第一光源1、第二光源2、光学处理组件3b、处理单元4及成像系统5。其中，光学处理组件3b包括中继整形组件31、位于中继整形组件31出光光路上的合光装置32、位于光导向元件22出光光路上的第一光引导元件33、以及沿合光装置32出光光路依次设置的第一中继透镜组34、波长转换装置350、收光中继透镜组36、散射元件37、以及第二中继透镜组38。成像系统5包括空间光调制器51、投影镜头52a及光机系统53。在本具体实施方式中，投影系统100与图2所示的不同之处在于：本实施方式中波长转换装置350为反射式波长转换装置，且投影系统100还包括第二光引导元件 43及第三中继透镜组45。
第三中继透镜组45与第一中继透镜组34相对设置。第二光引导元件43设置在第一中继透镜组34及第三中继透镜组45之间的光路上。第三中继透镜组45由一个或多个凸透镜及/或一个或多个凹透镜组成。从所述合光装置32合光后的照明光场光斑通过第三中继透镜组45、第二光引导元件43、第三中继透镜组45后进入波长转换装置350。由波长转换装置350出射的光束通过第三中继透镜组45、然后被第二光引导元件43反射至被所述收光中继透镜组36收光。通过所述收光中继透镜组36之后的光路与图2所示相同，在此不再赘述。
请参阅图5，图5所示为投影系统100运行时，处理单元4所需执行的软件模块，以生成对所述第一光源1、第二光源2及空间光调制器51、51a进行控制的控制信号。所述软件模块存储于存储单元6中、由处理单元4调用。所述软件模块包括第一光源亮度控制模块401与第二光源亮度控制模块402，其中第一光源亮度控制模块401用于至少根据待投影图像帧的像素灰度信号与第一光源1的最大亮度生成对应第一光源1的照明区域的亮度分布信号(下称“第一光源亮度分布信号”)，并输出第一光源亮度分布信号至第一光源1的照明区域以产生第一照明光场。具体地，在一种实施方式中，第一光源亮度控制模块401根据对应待投影图像帧像素灰度信号的亮度分布信号(下称“图像亮度分布信号”)与第一光源1的最大亮度生成第一光源亮度分布信号。第二光源亮度控制模块402用于根据所述图像帧的像素灰度信号以及第一光源亮度分布信号，生成控制光导向元件22的亮度分布信号(下称“第二光源亮度分布信号”)，以控制光导向元件22生成第二照明光场。第一照明光场与第二照明光场在合光装置32处合光，形成复合光场。
具体地，第二光源亮度控制模块402根据图像亮度分布信号与第一光源亮度分布信号的差值计算剩余照明光分布，再根据剩余照明光分布生成第二光源亮度分布信号。
进一步地，所述软件模块还包括电光转换模块403，电光转换模块403用于将所述图像帧的像素灰度信号转换成图像亮度分布信号，所述图像亮度分布信号被发送给第一光源亮度控制模块401与第二亮度控制模块402，以使第一光源亮度控制模块401与第二亮度控制模块402分别生成第一光源亮度分布信号与第二光源亮度分布信号。所述电光转换模块403根据一电光转 换函数(EOTF)实施上述功能，电光转换函数根据后期制作和图像信号的特点生成，例如PQ函数，HLG函数以及根据图像内容动态生成的转换函数。
进一步地，所述软件模块还包括复合照明光分布计算模块404与补偿像素灰度模块405。复合照明光分布计算模块404用于根据第一光源亮度分布信号与第二光源亮度分布信号计算一复合的亮度分布信号(下称“总亮度分布信号”)。补偿像素灰度模块405用于根据图像亮度分布信号与总亮度分布信号之间的差异，补偿所述图像帧的像素灰度信号以生成并输出图像信号至空间光调制器51、51a。
可以理解，第二光源2的发光单元21的亮度可设置为可调或不可调。当发光单元21的亮度可调时，处理单元4还可进一步根据待投影图像帧的亮度需求调节发光单元21的亮度。过程具体可为：第二光源亮度控制模块根据第二光源亮度分布信号，生成对应发光单元21的亮度控制信号，以根据光导向元件22所需的亮度调节发光单元21的亮度。
可以理解，由于光导向元件22的特性，光导向元件22并不能将所有的光能均集中至需増亮的区域，相反的，其他不需要增亮的区域亦会有一定量的残留亮度(下称“滞留亮度”)。针对这种情况，在一种实施方式中，第一光源亮度控制模块401根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)与第一光源最大亮度确定光导向元件22的光减小区域与光增加区域，并根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)、第一光源最大亮度及光导向元件22的光减小区域的滞留亮度生成第一光源亮度分布信号。
具体地，第一光源亮度控制模块401根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)与第一光源最大亮度生成前置亮度分布信号，再计算前置亮度分布信号与光导向元件22光减小区域的滞留亮度的差值获得第一光源亮度分布信号。
当发光单元21的亮度不可调时，在光导向元件22的光增加区域的亮度增加已满足需求、发光单元21输出的光能还有剩余的情况下，第二光源亮度控制模块402还可根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)以及第一光源亮度分布信号确定光导向元件22的光减小区域与光增加区域，计算光增加区域所需增加的亮度，及根据发光单元21输出的光能以及光增加区域所需增加的亮度计算光减小区域的亮度分布，从而获得 第二光源亮度分布信号。
具体地，在一种实施方式中，第二光源亮度控制模块402将满足光增加区域所需增加的亮度后的剩余光能均分至光减小区域的每一单位区域。
请参阅图6所示，为本发明实施方式提供的投影显示方法的方法流程图，所述方法可用于上述介绍的投影系统100，以下结合投影系统100介绍所述投影显示方法，所述方法具体包括步骤如下。
步骤S601，第一光源亮度控制模组401至少根据待投影图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)以及第一光源1的最大亮度生成第一光源亮度分布信号，并输出第一光源亮度分布信号至第一光源1的多个照明区域以生成第一照明光场。
步骤S602，第二光源亮度控制模块402根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)及第一光源亮度分布信号，生成控制光导向元件22的第二光源亮度分布信号，以控制光导向元件22生成第二照明光场。
步骤S603，合光装置32复合所述第一照明光场与第二照明光场以生成一复合光场。所述合光方式可以是偏振态合光、波长合光或者空间角度合光。
步骤S604，通过光学处理组件3、3a继续将复合光场引导至空间光调制器51、51a，利用复合光场照明空间光调制器51、51a，以使空间光调制器51、51a在对应所述图像帧的图像信号的控制下，输出携带图像信息的图像光。
可以理解，光学处理组件3、3a在将复合光场引导至空间光调制器51、51a的过程中，还可包括对复合光场进行波长转换之类的处理。
可以理解，步骤S602还可包括：第二光源亮度控制模块402根据图像亮度分布信号与第一光源亮度分布信号的差值计算剩余照明光分布，根据剩余照明光分布生成控制所述光导向元件的第二光源亮度分布信号。
可以理解，在步骤S601之前，所述方法还可包括步骤S600：电光转换模块403将所述图像帧的像素灰度信号转换成图像亮度分布信号。
可以理解，所述方法还可包括步骤：步骤S605，复合照明光分布计算模块404根据第一光源亮度分布信号与第二光源亮度分布信号计算总亮度分布信号；步骤S606，补偿像素灰度模块405根据对应所述图像帧的像素灰度信号的亮度分布信号与总亮度分布信号，补偿所述图像帧的像素灰度信号以生 成所述图像信号、及输出所述图像信号至所述空间光调制器51、51a。
可以理解，当发光单元21亮度可调时，所述方法还可包括步骤：第二光源亮度控制模块根据第二光源亮度分布信号生成对应发光单元21的亮度控制信号，以根据光导向元件22所需的亮度调节发光单元21的亮度。
可以理解，步骤S601还可包括如下步骤，请参阅图7所示。
步骤S701，第一光源亮度控制模组401根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)与第一光源最大亮度确定光导向元件22的光减小区域与光增加区域。
步骤S702，第一光源亮度控制模组401根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)、所述第一光源最大亮度及光导向元件22的光减小区域的滞留亮度生成第一光源亮度分布信号。
可以理解，步骤S702可进一步包括步骤如下，请参阅图8所示。
步骤S801，第一光源亮度控制模组401根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)与所述第一光源最大亮度生成一前置亮度分布信号。
步骤S802，第一光源亮度控制模组401计算前置亮度分布信号与光导向元件22光减小区域的滞留亮度的差值获得第一光源亮度分布信号。
可以理解，步骤S602可进一步包括步骤如下，请参阅图9所示。
步骤S901，第二光源亮度控制模块402根据所述图像帧的像素灰度信号(具体可以为：根据图像亮度分布信号)以及第一光源亮度分布信号确定光导向元件22的光减小区域与光增加区域。
步骤S902，第二光源亮度控制模块402计算光增加区域所需增加的亮度。
步骤S903，第二光源亮度控制模块402根据发光单元21输出的光能以及光增加区域所需增加的亮度，计算光减小区域的亮度分布，从而获得第一光源亮度分布信号。
可以理解，步骤S903还可包括：将满足所述光增加区域所需增加的亮度后的剩余光能均分至所述光减小区域的每一单位区域。
本发明的投影系统100，处理单元4接收一幅待投影图像的像素灰度信号，并且对应第一光源1照明区域的分区分割图像得到多个图像分区。处理单元4计算每个图像分区的亮度，并且生成对应每个图像分区的第一光源1与第二光源2的控制信号。处理单元4根据所述控制信号控制所述第一光源 1，以使第一光源1根据待投影图像实现区域照明局部减暗的效果。处理单元4控制第二光源2的光导向元件22，进行相位调制或改变光程差亦得到一明暗分布的照明光场。所述处理单元4根据第一光源1与第二光源2复合后的照明光源的亮度分布及待投影图像的像素灰度信号产生补偿控制信号。空间光调制器51、51a依据补偿后的控制信号调制所述第一光源1及第二光源2发出的光束对应的亮度来获得图像光，进而通过所述投影镜头52投影显示画面。
本发明通过区域照明局部减暗(Local Dimming)及光导向技术，能够大大增加光导向元件22所在分支的峰值亮度，再以叠加均匀光场以大大增加画面的峰值亮度。而通过第一光源1的均匀照明分支来增加画面的平均亮度。
请参阅图10A-10D，所示为区域照明局部减暗(Local Dimming)及光导向技术各自及结合能够呈现的光场亮度分布示意图。图10A所示为采用区域照明局部减暗技术(local dimming)的光场调制所能达到的亮度分布。其中标号1001代表了显示匀色画面时投影系统100能达到的最大亮度。标号1002为各区域减暗的比例。标号1003为减暗后各个区域的亮度分布。可以看到，区域照明局部减暗技术无法突破均匀白场时的亮度，画面的峰值亮度即等于白场时的最大亮度。通过局部减暗，只能够减少画面暗场的漏光，从而降低了黑色区域的亮度，达到增加对比度的目的。
图10B所示为光导向技术的亮度分布示意图。其中标号1004表示了单独利用光导向技术时投影系统100显示均匀白场时的最大亮度。由于光导向技术能够控制输出光场的空间亮度分布，因此可以把画面中暗场的照明光导向到亮场部分。因此光导向技术能够达到的峰值亮度要远大于显示均匀白场时的亮度，如图标号1006所示。标号1005表示其他区域剩余亮度。但是光导向技术并不能增加投影系统100输出的总流明数，即画面的总流明数是常数。因此画面中暗场越暗，亮场所占的比例越小，则峰值亮度越高，对比度越高。对于画面中大部分是亮场或中灰亮度的像素的情况下，光导向技术不得不分出大部分流明数来照明中灰和较暗区域，使得能够用于峰值亮度像素的流明数不足，限制了光导向技术在一般应用场景下的最大亮度(峰值亮度)。
同时由于光导向元件的限制，一般能够承受的光通量并不大，为了增加画面的总流明数，在光导向技术的基础上会加入均匀照明的补光光场1007，如图10C所示。则画面中的中灰、较暗像素的亮度主要由均匀补光光场提供， 光导向设备能够把大部分能够导向控制的光都集中到峰值亮度像素附近，从而能够在大部分的场景下显示很高的峰值亮度。但是由于均匀照明光场的加入，使得画面中黑场的照明光大大增加，从而加重了黑场时候的漏光，增加了画面中黑像素的亮度，从一个方面降低了画面能够达到的对比度。
图10D为本发明实施方式介绍的光导向技术和区域照明局部减暗技术相结合后的亮度空间分布示意图，也即是图10A与图10B的叠加后的技术效果。画面首先由局部减暗技术生产低频的照明光场，保证画面中中灰和低亮度像素的照明，然后对于超出局部减暗光源最大亮度的像素，由光导向技术分配光场进行补光，从而达到降低黑场亮度，增加峰值亮度的目的，能够达到比这两项技术单独使用更好的效果。
综上所述，本发明提供的投影系统是将利用两个照明光源产生第一和第二两个照明光场，第一照明光场使用区域照明局部减暗技术根据画面的内容产生明暗分布的背景照明光；第二照明光场利用光导向技术产生另一明暗分布的照明光，第一和第二照明光在空间光调制器前合光后形成复合照明光场照明空间光调制器，从而达到同时增加画面峰值亮度和降低画面黑场亮度的目的，从而增加投影系统的顺序和帧内对比度，以实现高亮度高动态范围图像的功能。
对于本领域技术人员而言，显然本发明不限于上述示范性实施例的细节，而且在不背离本发明的精神或基本特征的情况下，能够以其他的具体形式实现本发明。因此，无论从哪一点来看，均应将实施例看作是示范性的，而且是非限制性的，本发明的范围由所附权利要求而不是上述说明限定，因此旨在将落在权利要求的等同要件的含义和范围内的所有变化涵括在本发明内。不应将权利要求中的任何附图标记视为限制所涉及的权利要求。此外，显然“包括”一词不排除其他单元或步骤，单数不排除复数。装置权利要求中陈述的多个单元或装置也可以由同一个单元或装置通过软件或者硬件来实现。
以上所述仅为本发明的实施方式，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (20)

  1. 一种投影系统，包括：
    第一光源，所述第一光源为一阵列光源，所述第一光源被分成多个照明区域，每一照明区域可被独立控制以使所述第一光源产生明暗可调制的第一照明光场；
    第二光源，所述第二光源包括发光单元与光导向元件；所述光导向元件用以将发光单元发出的照明光重新分布以产生明暗可调制的第二照明光场，所述第二照明光场与第一照明光场叠加产生一复合光场；以及
    处理单元，执行的软件模块包括：
    第一光源亮度控制模块，用于至少根据待投影图像帧的像素灰度信号与所述第一光源最大亮度生成对应所述第一光源照明区域的亮度分布信号，并输出所述亮度分布信号至所述第一光源的照明区域以产生所述第一照明光场；及
    第二光源亮度控制模块，用于根据所述图像帧的像素灰度信号以及对应所述第一光源照明区域的亮度分布信号，生成控制所述光导向元件的亮度分布信号，以控制所述光导向元件生成所述第二照明光场；及
    空间光调制器，所述空间光调制器用于根据所述处理单元输出的图像信号调制所述复合光场，以产生携带图像信息的图像光。
  2. 如权利要求1所述的投影系统，其特征在于：所述光导向元件为相位调制液晶或者变形镜。
  3. 如权利要求1所述的投影系统，其特征在于，所述第二光源亮度控制模块用于根据对应所述图像帧的像素灰度信号的亮度分布信号与对应所述第一光源照明区域的亮度分布信号的差值计算剩余照明光分布，根据剩余照明光分布生成控制所述光导向元件的亮度分布信号。
  4. 如权利要求3所述的投影系统，其特征在于，所述处理单元还执行软件模块：电光转换模块，所述电光转换模块用于将所述图像帧的像素灰度信号转换成对应的所述亮度分布信号。
  5. 如权利要求4所述的投影系统，其特征在于，所述处理单元还执行软件模块：
    复合照明光分布计算模块，用于根据对应所述第一光源照明区域的亮度分布信号与对应所述光导向元件的亮度分布信号计算一复合的亮度分布信 号；及
    一补偿像素灰度模块，用于根据对应所述图像帧的像素灰度信号的亮度分布信号与复合的亮度分布信号，补偿所述图像帧的像素灰度信号以生成所述图像信号并输出至所述空间光调制器。
  6. 如权利要求3所述的投影系统，其特征在于，所述第二光源的发光单元亮度可调，所述第二光源亮度控制模块还用于根据所述光导向元件的亮度分布信号，生成对应所述发光单元的亮度控制信号，以根据所述光导向元件所需的亮度调节所述发光单元的亮度。
  7. 如权利要求3或6所述的投影系统，其特征在于，所述第一光源亮度控制模块用于根据所述图像帧的像素灰度信号与所述第一光源最大亮度确定所述光导向元件的光减小区域与光增加区域，并根据所述图像帧的像素灰度信号、所述第一光源最大亮度及所述光导向元件的光减小区域的滞留亮度生成所述第一光源照明区域的所述亮度分布信号。
  8. 如权利要求7所述的投影系统，其特征在于，所述第一光源亮度控制模块根据所述图像帧的像素灰度信号与所述第一光源最大亮度生成一前置亮度分布信号，再计算所述前置亮度分布信号与所述光导向元件光减小区域的滞留亮度的差值获得对应所述第一光源照明区域的所述亮度分布信号。
  9. 如权利要求3所述的投影系统，其特征在于，所述第二光源亮度控制模块根据所述图像帧的像素灰度信号以及对应所述第一光源照明区域的所述亮度分布信号确定所述光导向元件的光减小区域与光增加区域及计算所述光增加区域所需增加的亮度、根据所述发光单元输出的光能以及所述光增加区域所需增加的亮度计算所述光减小区域的亮度分布，从而获得所述光导向元件的所述亮度分布信号。
  10. 如权利要求9所述的投影系统，其特征在于，所述第二光源亮度控制模块将满足所述光增加区域所需增加的亮度后的剩余光能均分至所述光减小区域的每一单位区域。
  11. 一种投影显示方法，其特征在于，包括：
    至少根据待投影图像帧的像素灰度信号以及一第一光源的最大亮度生成对应所述第一光源多个照明区域的亮度分布信号，并输出所述亮度分布信号至所述第一光源的多个照明区域以生成一第一照明光场；
    根据所述图像帧的像素灰度信号以及对应所述第一光源多个照明区域的 亮度分布信号，生成控制一光导向元件的亮度分布信号，以控制所述光导向元件生成一第二照明光场；
    复合所述第一照明光场与第二照明光场以生成一复合光场；
    利用所述复合光场照明一空间光调制器，以使所述空间光调制器在对应所述图像帧的图像信号的控制下，输出携带图像信息的图像光。
  12. 如权利要求11所述的投影显示方法，其特征在于，生成控制所述光导向元件的亮度分布信号的步骤包括：根据对应所述图像帧的像素灰度信号的亮度分布信号与对应所述第一光源照明区域的亮度分布信号的差值计算剩余照明光分布，根据剩余照明光分布生成控制所述光导向元件的亮度分布信号。
  13. 如权利要求12所述的投影显示方法，其特征在于，还包括步骤：将所述图像帧的像素灰度信号转换成对应的所述亮度分布信号。
  14. 如权利要求13所述的投影显示方法，其特征在于，还包括步骤：根据对应所述第一光源照明区域的亮度分布信号与对应所述光导向元件的亮度分布信号计算一复合的亮度分布信号；
    根据对应所述图像帧的像素灰度信号的亮度分布信号与复合的亮度分布信号，补偿所述图像帧的像素灰度信号以生成所述图像信号；及
    输出所述图像信号至所述空间光调制器。
  15. 如权利要求12所述的投影显示方法，其特征在于：还包括步骤：根据所述光导向元件的所述亮度分布信号，生成照明所述光导向元件的一发光单元的亮度控制信号，以根据所述光导向元件所需的亮度调节所述发光单元。
  16. 如权利要求12或15所述的投影显示方法，其特征在于，生成对应所述第一光源多个照明区域的所述亮度分布信号的步骤包括：
    根据所述图像帧的像素灰度信号与所述第一光源最大亮度确定所述光导向元件的光减小区域与光增加区域；及
    根据所述图像帧的像素灰度信号、所述第一光源最大亮度及所述光导向元件的光减小区域的滞留亮度生成所述第一光源照明区域的所述亮度分布信号。
  17. 如权利要求16所述的投影显示方法，其特征在于，根据所述图像帧的像素灰度信号、所述第一光源最大亮度及所述光导向元件的光减小区域的滞留亮度生成所述第一光源照明区域的所述亮度分布信号的步骤包括：
    根据所述图像帧的像素灰度信号与所述第一光源最大亮度生成一前置亮度分布信号；及
    根据所述前置亮度分布信号与所述光导向元件光减小区域的滞留亮度的差值计算获得对应所述第一光源照明区域的所述亮度分布信号。
  18. 如权利要求12所述的投影显示方法，其特征在于，生成所述光导向元件的所述亮度分布信号的步骤包括：
    根据所述图像帧的像素灰度信号以及对应所述第一光源照明区域的所述亮度分布信号确定所述光导向元件的光减小区域与光增加区域；
    计算所述光增加区域所需增加的亮度；及
    根据照明所述光导向元件的一发光单元输出的光能以及所述光增加区域所需增加的亮度，计算所述光减小区域的亮度分布，从而获得所述光导向元件的所述亮度分布信号。
  19. 如权利要求18所述的投影显示方法，其特征在于，计算所述光减小区域的亮度分布包括：将满足所述光增加区域所需增加的亮度后的剩余光能均分至所述光减小区域的每一单位区域。
  20. 如权利要求11所述的投影显示方法，其特征在于，复合所述第一照明光场与第二照明光场的方式为偏振态合光、波长合光或者空间角度合光。
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