CN107765497B - Light emitting device, projection system, and image modulation method - Google Patents
Light emitting device, projection system, and image modulation method Download PDFInfo
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- CN107765497B CN107765497B CN201610678344.7A CN201610678344A CN107765497B CN 107765497 B CN107765497 B CN 107765497B CN 201610678344 A CN201610678344 A CN 201610678344A CN 107765497 B CN107765497 B CN 107765497B
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- 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
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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
- H04N9/3155—Modulator illumination systems for controlling the light source
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The light emitting device can emit first color light, wherein a period of emitting the first color light by the light emitting device at least comprises a first sub-period and a second sub-period, and the light intensity of the first color light emitted by the light emitting device in the first sub-period is different from that in the second sub-period. The invention also provides a projection system and an image modulation method.
Description
Technical Field
The present invention relates to the field of projection technologies, and in particular, to a light emitting device, a projection system, and an image modulation method.
Background
The conventional projection system generally comprises a light emitting device, a light valve and a control device, wherein the light emitting device emits three colors of red, green and blue, and the control device acquires input image data and controls the light valve to receive the three colors of light and modulate an image according to the input image data. However, the light emitting device often has a problem that the brightness of a certain color picture is poor due to the insufficient color light (such as insufficient red light) caused by the poor efficiency of fluorescent powder, aging and the like, which affects the projection picture effect of the projection system.
Disclosure of Invention
In order to solve the technical problem of poor projection screen effect of the projection system in the prior art, it is necessary to provide a light emitting device, a projection system and an image modulation method applied to the projection system, which can solve the above problems.
The light emitting device can emit first color light, wherein a period of emitting the first color light by the light emitting device at least comprises a first sub-period and a second sub-period, and the light intensity of the first color light emitted by the light emitting device in the first sub-period is different from that in the second sub-period.
Further, the light emitting device includes:
a light source for emitting light;
the wavelength conversion device is arranged in a transmission path of light emitted by the light source, the wavelength conversion device can periodically emit light with different colors according to time sequence under the irradiation of the light source, the movement period of the wavelength conversion device is set to be one wavelength conversion device period, the period of emitting the first color light by the wavelength conversion device in one wavelength conversion device period at least comprises a first sub-period and a second sub-period, and the light intensity of the first color light emitted by the wavelength conversion device in the first sub-period is different from that of the light intensity of the first color light emitted by the wavelength conversion device in the second sub-period.
Further, the light emitting device further includes a light source driving module for driving the light source, and the value of the first current for driving the light source is a first current value, where the first current value is set in the first sub-period; the second current value of the light source driving module set in the second sub-time period for driving the light source is a second current value, and the first current value is different from the second current value.
Further, at least one of the first current value and the second current value is a fixed value.
Further, at least one of the first current value and the second current value is time-varying.
Further, the light intensity of the first color light emitted by the wavelength conversion device in the first sub-period is greater than the light intensity of the first color light emitted by the wavelength conversion device in the second sub-period, and the first sub-period occurs before the second sub-period.
Further, the first color is red, and the first color light is red.
A projection system comprising a light emitting device as described above, a control device capable of acquiring input image data, and a light valve for image modulating a first color of an image during a period in which the light emitting device emits the first color of the image during each frame of image display period of the input image data.
Further, the time for modulating the first color by the light valve comprises a first color on state time and a first color off state time, the input image data comprises a first color input gray scale value, and the first color on state time corresponds to the first color input gray scale value.
Further, when the first color input gray scale value is set to be 1, the first color on state time of the light valve is set to be t, and when the first color input gray scale value is set to be Hx, the first color on state time of the light valve is set to be hx×t, wherein Hx is an integer greater than or equal to 0 and less than or equal to 255;
when the first color input gray scale value is set to be Hn, the first color on state time Hn multiplied by t of the first color input gray scale value Hn modulated by the light valve is equal to the first sub-time period, and when Hx is smaller than or equal to Hn, the first color input gray scale value Hx modulates first color light emitted by the light emitting device in the first sub-time period as a light source through the light valve; when the Hx is larger than the Hn, the n gray scales of the front section of the Hx are modulated by the first color light emitted by the first sub-time period as a light source, and the (x-n) gray scales of the rear section of the Hx are modulated by the light valve by the first color light emitted by the light emitting device in the second sub-time period as a light source.
Further, for a certain pixel point in the image, the relative relation curve formed by the preset output light intensity of the pixel point and the actual output light intensity of the pixel comprises at least two segments, wherein in each segment, the preset output light intensity of the pixel and the actual output light intensity of the pixel are in linear relation, or
The relative relation curve formed by the preset output light intensity of the pixel point and the actual output light intensity of the pixel is a continuous curve which monotonically increases.
An image modulation method applied to a projection system, a light emitting device of the projection system capable of generating a first color light, the image modulation method comprising:
acquiring a frame of input image data signal, and generating a first color light modulation signal according to the input image data signal, wherein the first color light modulation signal corresponds to first color gray scale image data, and the first color gray scale image data comprises first color input gray scale values of a first color at each pixel point;
the first color light modulation signal is input to a light valve of the projection system, the light valve carries out image modulation on corresponding light emitted by a light emitting device of the projection system according to the first color light modulation signal, a period of emitting the first color light by the light emitting device at least comprises a first sub-period and a second sub-period, and the light intensity of the first color light emitted by the light emitting device in the first sub-period is different from that of the light emitting device in the second sub-period.
Further, the step of inputting the first color light modulation signal to a light valve of the projection system, where the light valve performs image modulation on corresponding light emitted by a light emitting device of the projection system according to the first color light modulation signal further includes: the first color light modulation signal is input to a light valve of the projection system, and when the light valve carries out image modulation on corresponding light emitted by a light emitting device of the projection system according to the modulation signal, the method further comprises detecting the light emitted by the light emitting device of the projection system, generating a synchronization signal, and inputting the synchronization signal and the light modulation signal to the light valve so that the modulation signal of the light valve is synchronous with the corresponding light emitted by the light emitting device.
Further, the light intensity of the first color light emitted by the light emitting device in the first sub-period is greater than the light intensity of the first color light emitted by the light emitting device in the second sub-period, and the first sub-period occurs before the second sub-period.
An image modulation method applied to a projection system, a light emitting device of which is capable of emitting light of a first color at two different light intensities of the light of the first color, the image modulation method comprising:
Acquiring a frame of input image data signal, and generating a first color light modulation signal according to the input image data signal, wherein the first color light modulation signal corresponds to first color gray scale image data, and the first color gray scale image data comprises first color input gray scale values of a first color at each pixel point;
comparing a first color input gray level value of a pixel point with a preset gray level value, if the first color input gray level value is smaller than the preset gray level value, enabling the light-emitting device to emit light with higher first color light intensity when emitting first color light, and if the first color input gray level value is larger than or equal to the preset gray level value, enabling the light-emitting device to emit light with lower first color light intensity when emitting first color light;
the first color light modulation signal is input to a light valve of the projection system, the light emitting device is controlled to emit first color light according to the corresponding first color light intensity according to the comparison result, and the light valve carries out image modulation on the first color light emitted by the light emitting device of the projection system according to the first color light modulation signal.
Compared with the prior art, the light-emitting device, the projection system and the image modulation method applied to the projection system can emit the first color light with different light intensities, and the light valve is controlled to modulate the first color image according to the input image data, so that the first color picture with low gray scale can be matched with the subarea with stronger light intensity, the purpose of increasing the brightness of the first color picture with low gray scale is achieved, the brightness of the first color picture is higher, and the projection picture effect displayed by the projection system is better.
Drawings
Fig. 1 is a schematic view of a projection system according to a preferred embodiment of the present invention.
Fig. 2 is a plan view of a wavelength conversion device.
FIG. 3 is a timing diagram of a light valve and wavelength conversion device of the present invention.
Fig. 4 is a relative relationship between a preset output light intensity of a first color of a pixel of an output image and an actual output light intensity of the first color of the pixel according to an embodiment of the present invention.
Fig. 5 is a relative relationship between a preset output light intensity of a first color of a pixel of an output image and an actual output light intensity of the first color of the pixel according to another embodiment of the present invention.
Fig. 6 is a flowchart of an image modulation method applied to a projection system according to the present invention.
Fig. 7 is a flowchart of another image modulation method applied to a projection system according to the present invention.
Description of the main reference signs
Projection system 100
Light emitting device 10
Light source 11
Wavelength conversion device 13
Light source driving module 14
Wavelength conversion device driving module 15
First color region 131
First sub-region 1311
Second subregion 1313
Second color region 133
Third color region 135
Dodging device 16
Light valve 20
Control device 30
Projection lens 50
The invention will be further described in the following detailed description in conjunction with the above-described figures.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The following embodiments and features of the embodiments may be combined with each other without conflict.
In the present invention, when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element through a intervening element.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Referring to fig. 1, a projection system 100 according to a preferred embodiment of the present invention includes a light emitting device 10, a light valve 20, and a control device 30. The light emitting device 10 can emit light of different colors in time sequence. The light valve 20 is located in a transmission path of light emitted from the light emitting device 10, and is configured to perform image modulation on the light emitted from the light emitting device 10. The control device 30 is used for controlling the operation of the light emitting device 10, the light valve 20, and other functional modules of the projection system 100.
The light emitting device 10 includes a light source 11 and a wavelength conversion device 13. A light source 11 for emitting light; the wavelength conversion device 13 is configured to receive light emitted from the light source 11 and emit light of different colors in time sequence.
The light source 11 may be a conventional lamp or a solid state light source comprising a laser or a Light Emitting Diode (LED). For solid state light sources, the wavelength of light is typically in the range from 300nm to 500nm. For example, many LED manufacturers produce light emitting diodes (so-called blue LEDs) that emit light at 460 nm. One of the main advantages of solid state light sources compared to conventional bulbs, including mercury lamps, is its modulation capability. Both the laser and the LED may be modulated at frequencies above 1 Mhz. In this embodiment, the light source 11 emits blue excitation light.
Fig. 2 is a schematic plan view of the wavelength conversion device 13. In the present embodiment, the wavelength conversion device 13 is a substantially circular color wheel, and includes a first color region 131, a second color region 133, and a third color region 135 disposed along the circumferential movement direction thereof, and is configured to receive the light of the light source 11 and emit the first color light, the second color light, and the third color light, respectively. The first color region 131 includes a first sub-region 1311 and a second sub-region 1313. The first sub-region 1311, the second sub-region 1313, the second color region 133, and the third color region 135 are sequentially arranged in the circumferential direction. The first color region 131 is a red region, the second color region 133 is a green region, and the third color region 135 is a blue region. The first color light is red light, the second color light is green light, and the third color light is blue light.
In the present embodiment, the wavelength conversion device 13 is a transmissive wavelength conversion device, that is, light from the light source 11 enters from one side of the wavelength conversion device 13, and light of at least two colors is emitted from the other side of the wavelength conversion device 13. Preferably, at least one area (e.g. 131, 133, 135) on the wavelength conversion device 13 carries a wavelength conversion material, and the wavelength conversion material irradiated by the light source 11 onto the wavelength conversion device 13 is absorbed for wavelength conversion to generate light of other colors, so that the wavelength conversion device 13 emits light of different colors.
Specifically, in one embodiment, the first color region 131 of the wavelength conversion device 13 is provided with a first color light fluorescent material (e.g., a first color phosphor), the second color region 133 is provided with a second color light fluorescent material (e.g., a second color phosphor), and the third color region 135 is a transmissive region. Referring to fig. 3, a timing diagram of the light emitting device 10 of the present invention is shown. Specifically, fig. 3 is a light emission timing chart of the respective colors of light emitted from the light source 11 via the wavelength conversion device 13. When the light emitting device 10 is in operation, the wavelength conversion device 13 rotates around the center of its circumference, such that the first color region 131, the second color region 133, and the third color region 135 sequentially receive the light emitted from the light source 11, and sequentially emit the first color light, the second color light, and the third color light. It will be appreciated that when the light source 11 is an ultraviolet laser light source, the third color region 135 carries a third color light fluorescent material, and the third color light fluorescent material is a third color fluorescent powder, and when the light of the light source 11 irradiates the third color region 135, the third color fluorescent powder is excited to emit third color light. The wavelength converting material of the first, second and third color regions preferably emits light in the wavelength ranges 580nm to 700nm, 500nm to 580nm and 400nm to 500nm, respectively.
In this embodiment, the structure, shape, size, material composition, density, etc. of the first sub-area 1311 and the second sub-area 1313 are the same, i.e. the first color area 131 does not actually include two sub-areas, which is only convenient for the following description.
The first color region 131, the second color region 133, and the third color region 135 have the same shape and size on the wavelength conversion device 13. It is understood that the shapes and sizes of the first color region 131, the second color region 133 and the third color region 135 may be different. The area of the wavelength conversion device 13 receiving the excitation light is changed continuously, such as from red to green to blue, resulting in different colors of light. The rate of change of the color of the emitted light is directly related to the rotational speed of the wavelength converting device 13.
It will be appreciated that in another embodiment, the wavelength conversion device 13 may be a ribbon structure, or a cylindrical structure capable of being periodically rotated, which is capable of emitting light of different colors periodically and in time sequence.
The light source driving module 14 is configured to drive the light source 11, and to control the magnitude of the current value driving the light source 11 so as to change the intensity of the light emitted from the wavelength conversion device 13. In this embodiment, the period of time for which the wavelength conversion device 13 rotates one revolution is defined as one wavelength conversion device period, and the period of time for which the wavelength conversion device 13 emits the first color light in one wavelength conversion device period includes at least a first sub-period and a second sub-period. The light source driving module 14 is arranged in the first sub-time period, and drives the current value of the first color light R1 emitted by the light source 11 in the first color area 131 to be a first current value I1; the light source driving module 14 is disposed in the second sub-period, and drives the current value of the light source 11 irradiating the first color region 131 to emit the first color light R2 to be the second current value I2, where the first current value I1 is different from the second current value I2, so that the light intensities of the first color light emitted in the first sub-period and the second sub-period are different. Let the light emitted by the wavelength conversion device 13 in the first sub-period be the first color light R1, and let the light emitted by the wavelength conversion device 13 in the second sub-period be the first color light R2. The first color light R1 is different from the first color light R2 in light intensity. The period in which the first sub-region 1311 emits the first color light R1 is a first sub-period, and the period in which the second sub-region 1313 emits the first color light R2 is a second sub-period.
The wavelength conversion device driving module 15 is used for the wavelength conversion device 13 is driven to rotate.
Further, the light emitting device 10 further includes a light uniformizing device 16 for uniformizing the light emitted from the wavelength converting device 13.
The light valve 20 is located in the transmission path of the light emitted from the wavelength conversion device 13. The light emitted from the wavelength conversion device 13 can enter the light valve 20. The first color light, the second color light, and the third color light modulated by the light valve 20 are projected to form a pre-display image. It is understood that the light valve 20 may be LCD, LCoS, DMD, etc. Preferably, the light valve is selected to be a DMD.
The control device 30 is connected to the light source driving module 14 so that light source light of a predetermined wavelength band required for image generation can be emitted from the light emitting device 10. The control device 30 is connected to the wavelength conversion device driving module 15, and is used for controlling the rotation speed of the wavelength conversion device 13. The control device 30 is configured to receive input image data, and generate a first color light modulation signal to enable the light valve 20 to perform first color image modulation according to the first color light modulation signal during a period when the light emitting device 10 emits the first color light R1 and the first color light R2; the control device 30 can generate a second color light modulation signal according to the input image data to control the light valve 20 to perform second color image modulation according to the second color light modulation signal in a period when the light emitting device 10 emits the second color light; the control means 30 can generate a third color light modulation signal based on said input image data to cause the light valve 20 to perform a third color image modulation based on said third color light modulation signal during a period when the light emitting means 10 emits third color light. The input image data comprises input gray scale values of a first color, a second color and a third color at each pixel point.
In this embodiment, one frame of image display period corresponds to one frame of modulation output image period, one frame of image display period also corresponds to one wavelength conversion device period, and in each frame of image display period of the input image data, the light valve 20 performs image modulation on the first color of the image in the period when the light emitting device 10 emits the first color light.
In this embodiment, the first sub-time Duan Fa occurs before the second sub-time period.
Referring to fig. 3, in a period when the light valve 20 modulates a frame of output image, the light valve 20 includes a first color ON state time (e.g., an ON period) and a first color OFF state time (e.g., an OFF period), the frame of input image data includes first color gray scale data, the first color gray scale data includes a first color input gray scale value of each pixel point, the first color input gray scale value set at a certain pixel point is Hx, and the first color ON state time of the light valve 20 for the corresponding pixel point corresponds to the first color input gray scale value. For example, when the first color input gray level value is 1 gray level, the first color on-state time of the light valve 20 is t, and when the first color input gray level value is Hx, the first color on-state time of the light valve 20 is hx×t, where Hx may be any integer greater than or equal to 0 and less than or equal to 255 (i.e. the maximum gray level value Hm).
In this embodiment, the start point of the first color on state time of the light valve 20 is the same as the start point of the first sub-period no matter what the first color input gray scale value is, that is, when the first sub-region 1311 starts emitting the first color light R1, the light valve 20 starts entering the first color on state time, so as to perform image modulation according to the first color input gray scale value.
For example, let the first color input gray-scale value of a certain pixel point of a certain frame of input image data be Hn, the first color on-state time of the light valve 20 be hn×t, the first color on-state time hn×t is equal to the first sub-period, when the first color input gray-scale value of a certain pixel point is smaller than or equal to Hn, the first color on-state time hχ corresponding to the light valve 20 is smaller than or equal to hn×t, the first sub-period is fixed, and the starting point of the first color on-state time of the light valve 20 is the same as the starting point of the first sub-period, so that the first color input gray-scale value Hx of the corresponding pixel point is all modulated by the first color light R1 of the first sub-period as a light source, and the light with higher intensity for the smaller gray-scale value Hx in the input image data can be modulated by the light with higher intensity as the light source, thereby the lower gray-scale value Hx in the input image data can obtain a higher gray-scale area in the input image data.
Further, when the first color input gray scale value Hx is greater than Hn, the first color on state time hx×t corresponding to the light valve 20 is greater than hn×t, so that all the first n gray scales of the first color input gray scale value Hx are modulated by the light valve 20 by using the first color light R1 emitted by the wavelength conversion device 13 in the first sub-period as a light source, and the (x-n) gray scales of the second segment are modulated by the light valve 20 by using the first color light R2 emitted by the wavelength conversion device 13 in the second sub-period as a light source. Since the intensity of the first color light R2 is low, for a large input gray-scale value Hx, the light valve 20 is modulated by using not all the first color light R1 with high intensity as the light source but part of the first color light R2 with low intensity as the light source.
Referring to fig. 4, in an embodiment, the light source driving module 14 controls the first current value I1 and the second current value I2 to be fixed values, and for a certain pixel point in the output image, a relative relationship curve formed by the preset output light intensity of the first color of the pixel point and the actual output light intensity of the first color of the pixel point includes two segments, and in each segment, the preset output light intensity of the first color of the pixel point and the actual output light intensity of the first color of the pixel point are linearly changed. The first current value I1 is greater than the second current value I2, so that the light intensity of the first color light R1 emitted in the first sub-period is greater than the light intensity of the first color light R2 emitted in the second sub-period. For a first color input gray-scale value smaller than or equal to Hn in the input image data, the light valve 20 uses the first color light R1 emitted by the wavelength conversion device 13 in the first sub-period as a light source to modulate, and the slope of a line segment (K1) formed by the preset output light intensity of the first color of the pixel point and the actual output light intensity of the first color of the pixel point is larger; for a first color input gray-scale value when the input image data is greater than Hn, the light valve 20 modulates using the first color light R1 emitted by the wavelength conversion device 13 in the first sub-period and the first color light R2 emitted by the second sub-period as light sources. Since the light intensity of the first color light R2 is smaller than that of the first color light R1, the slope of a line segment (K2) formed by the preset output light intensity of the first color of the pixel point and the actual output light intensity of the first color of the pixel is smaller than that of K1.
It can be understood that when the number of the sub-periods is greater than two, that is, the driving currents of the light source driving module 15 in the sub-periods are fixed values and different, the relative relationship curve formed by the preset output light intensity of the first color of the pixel point and the actual output light intensity of the first color of the pixel point is formed by a plurality of segments, and in each segment, the line formed by the preset output light intensity of the first color of the pixel point and the actual output light intensity of the first color of the pixel point is linearly changed.
For example, let the first color input gray-scale value Hn be 128, let the first color input gray-scale value Hx be 100 at a certain pixel, and when the light valve 20 performs image modulation, all of the first color input gray-scale values 100 at the corresponding pixel are modulated by the first color light R1 emitted by the wavelength conversion device 13 in the first sub-period as a light source. For example, when the first color input gray-scale value Hx provided at a certain pixel is 128 and the light valve 20 performs image modulation, the first color input gray-scale value 128 is modulated by the wavelength conversion device 13 as a light source in the first sub-period of the first color light R1 at the corresponding pixel. For another example, hn is 128, the first color input gray-scale value Hx set at a certain pixel is 200, and when the light valve 20 performs image modulation, at the corresponding pixel, the first 128 gray-scales of the first color input gray-scale value 200 are modulated by the first color light R1 emitted by the wavelength conversion device 13 in the first sub-period as a light source (i.e., the first color light R1 emitted by the first sub-region 1311 in the first 128 gray-scales is modulated by the first color light R2 in the second sub-period as a light source), and the second 72 gray-scales are modulated by the first color light R2 in the second sub-period (i.e., the second 72 gray-scales are modulated by the first color light R2 emitted by the second sub-region 1313 as a light source).
Further, the fluorescent materials of the first sub-region 1311 and the second sub-region 1313 have the same composition, density, area, etc., and the current for driving the light source 11 is controlled by the light source driving module 14, so that the optical density of the first color light R1 emitted from the first sub-region 1311 is 3 times that of the second sub-region 1313. For example, when the intensity of the first color light in a certain area is preset to be S in the input image data, the intensity of the emitted first color light is S. When the intensity of the first color light in a certain area is preset to be 0.5 in the input image data, the intensity of the emergent first color light is 0.75S.
It is understood that at least one of the first current value I1 and the second current value I2 is a fixed value.
It is understood that at least one of the first current value I1 and the second current value I2 is time-varying.
Further, the projection system 100 further includes a projection lens 50 for projecting and displaying the image modulated by the light valve 20.
In another embodiment, the first current value I1 is time-varying during the first sub-period, and the second current value I2 is time-varying during the second sub-period, so as to avoid a problem of uncomfortable visual experience during viewing caused by a sudden color difference change at the boundary area between the first sub-region 1311 and the second sub-region 1313. Referring to fig. 5, a relative relationship curve formed by a preset output light intensity of a first color of a certain pixel point in an output image and an actual output light intensity of the first color of the pixel is a monotonically increasing curve.
The formula of the outgoing light intensity-image light intensity curve is set as follows:
y＝f(x)，
let the formula of the "gray-scale-visual intensity curve" of the human eye for the first color light be:
Y＝F(y)，
then the first time period of the first time period,
Y＝F(f(x))，
wherein x is the gray scale value of the chromatic light, and Y is the brightness perceived by human eyes, so that the brightness seen by human eyes and the image brightness are in linear relation, and the problem of chromatic aberration caused by low resolution of the brightness of human eyes when the image brightness is low is avoided.
It is understood that the light emitting device 10 may omit the light source driving module 14, and perform driving control by providing the light source driving module to the control device 30; the light emitting device 10 may omit the wavelength conversion device driving module 15, and perform driving control by providing the wavelength conversion device driving module to the control device 30.
It will be appreciated that in an embodiment, the wavelength conversion device 13 may be arranged to be reflective.
It is understood that the number of sub-areas of the first color area 131 is not limited to two sub-areas, and may be three or more, i.e., the sub-period may be three or more.
It is understood that the period of emitting the first color light is not limited to include at least two sub-periods, the period of emitting the second color light may also include at least two sub-periods, and the period of emitting the third color light may also include at least two sub-periods.
It will be appreciated that the first color region of the wavelength conversion device 13 includes at least a first sub-region and a second sub-region, where the phosphor material or density of the first sub-region is different from the phosphor material or density of the second sub-region, so that the light intensity of the first color light emitted by the first sub-region is different from the light intensity of the first color light emitted by the second photon region under the same excitation light irradiation.
It will be appreciated that the first sub-time Duan Fa is not limited to be before the second sub-time period, that is, the first sub-time Duan Fa is after the second sub-time period, and the order of emitting the color light by the wavelength conversion device 13 is the first color light R2, the first color light R1, the third color light, the second color light, and the first color light R2 … ….
It is understood that the start point of the first color on state time may be different from the start point of the first sub-period.
It will be appreciated that the phosphor material or density of the first sub-region 1311 is different from the phosphor material or density of the second sub-region 1313 such that under illumination by the light source 11, the intensity of the first color light emitted by the first sub-region 1311 is different from the intensity of the first color light emitted by the second sub-region 1313. In this embodiment, the density of the phosphor of the first subregion 1311 is 3 times that of the phosphor of the second subregion 1313. The phosphor density of both the first sub-region 1311 and the second sub-region 1313 is uniform. Let the first color light emitted by the first sub-region 1311 be the first color light R1, and let the first color light emitted by the second sub-region 1313 be the first color light R2.
It will be appreciated that the phosphor density on both the first and second sub-regions 1311, 1313 of the wavelength conversion device 13 of the projection system 100 is varied.
The invention also provides an image modulation method applied to the projection system, referring to figure 6 of the drawings in which, the light emitting device of the projection system is capable of generating a first color light, and the image modulation method comprises:
step 601, obtaining a frame of input image data signal, and generating a first color light modulation signal according to the input image data signal, wherein the first color light modulation signal corresponds to first color gray scale image data, and the first color gray scale image data comprises first color input gray scale values of a first color at each pixel point.
Step 602, inputting the first color light modulation signal to a light valve of the projection system, wherein the light valve performs image modulation on corresponding light emitted by a light emitting device of the projection system according to the first color light modulation signal, a period of emitting the first color light by the light emitting device at least includes a first sub-period and a second sub-period, and light intensities of the first color light emitted by the light emitting device in the first sub-period and the second sub-period are different.
In this embodiment, the first color light modulation signal is input to a light valve of the projection system, and when the light valve performs image modulation on corresponding light emitted by a light emitting device of the projection system according to a modulation signal, the method further includes detecting the light emitted by the light emitting device of the projection system, generating a synchronization signal, and inputting the synchronization signal and the light modulation signal to the light valve so that the modulation signal of the light valve is synchronized with the corresponding light emitted by the light emitting device.
In the period of modulating the one-frame output image, the light valve includes a first color ON-state time (for example, an ON period) and a first color OFF-state time (for example, an OFF period), where the first color input gray scale value of the one-frame input image data at a certain pixel point is Hx, and the first color ON-state time of the corresponding pixel point corresponds to the first color input gray scale value. For example, when the first color input gray level value is 1 gray level, the first color on-state time of the light valve 20 is t, and when the first color input gray level value is Hx, the first color on-state time of the light valve 20 is hx×t, where Hx may be any integer greater than or equal to 0 and less than or equal to 255 (i.e. the maximum gray level value Hm).
In this embodiment, no matter how many first color input gray-scale values are, the starting point of the first color on-state time of the light valve is the same as the starting point of the first sub-period, that is, when the light emitting device starts emitting the first color light R1, the light valve starts entering the first color on-state time, so that image modulation is performed according to the first color input gray-scale values.
For example, let the first color input gray-scale value of a certain pixel point of a certain frame of input image data be Hn, the first color on-state time of the light valve be hn×t, the first color on-state time hn×t is equal to the first sub-time period, when the first color input gray-scale value of a certain pixel point is smaller than or equal to Hn, the first color on-state time hx×t corresponding to the light valve is smaller than or equal to hn×t, the first sub-time period is fixed, and the starting point of the first color on-state time of the light valve is the same as the starting point of the first sub-time period, so that the first color input gray-scale value Hx at the corresponding pixel point is all modulated by the first color light R1 of the first sub-time period, and because the intensity of the first color light R1 is higher, the smaller gray-scale value Hx in the input image data can be modulated by the higher intensity, so that the lower gray-scale area in the input image data can obtain higher brightness.
Further, when the first color input gray scale value Hx is greater than Hn, the first color on state time hx×t corresponding to the light valve is greater than hn×t, so that all the n gray scales in the front section of the first color input gray scale value Hx modulate the first color light R1 emitted by the wavelength conversion device in the first sub-period by the light valve as a light source, and the (x-n) gray scales in the rear section modulate the first color light R2 emitted by the wavelength conversion device in the second sub-period by the light valve as a light source. Since the intensity of the first color light R2 is low, the gray scale value Hx is input for the larger first color, and the light valve is modulated by using the lower first color light R2 as the light source instead of using the higher first color light R1 as the light source.
In another embodiment, the present invention further provides an image modulation method applied to a projection system, where the light emitting device of the projection system can emit light of a first color with two different light intensities of the light of the first color, referring to fig. 7, the image modulation method includes:
step 701, obtaining a frame of input image data signal, and generating a first color light modulation signal according to the input image data signal, where the first color light modulation signal corresponds to first color gray scale image data, and the first color gray scale image data includes a first color input gray scale value of a first color at each pixel point.
Step 702, comparing a first color input gray level value of a pixel with a preset gray level value. If the first color input gray scale value is smaller than the preset gray scale value, the light emitting device emits light with higher first color light intensity when emitting first color light; if the first color input gray level value is greater than or equal to the preset gray level value, the light emitting device emits light with a lower first color light intensity when emitting the first color light. In this embodiment, the preset gray-scale value is pre-stored in the control device of the projection system, where the preset gray-scale value is 128, so that the light valve of the projection system uses brighter light as the light source when modulating the first color input value with a lower value.
Step 703, inputting the first color light modulation signal to a light valve of the projection system, and controlling the light emitting device to emit first color light according to the corresponding first color light intensity according to the comparison result, wherein the light valve performs image modulation on the first color light emitted by the light emitting device of the projection system according to the first color light modulation signal. In this embodiment, the actual first color light intensity value is increased by adjusting and increasing the driving current of the light source driving the light emitting device.
Compared with the prior art, the wavelength conversion device 13, the light emitting device 10, the projection system 100 and the image modulation method applied to the projection system 100 provided by the invention have the advantages that the wavelength conversion device 13 is adopted, the period of emitting the first color light by the light emitting device 10 at least comprises two sub-periods, the light intensities of the first color light emitted by the two sub-periods are different, the light valve 20 is controlled to modulate the first color image according to the input image data, the first color picture with low gray level can be matched with the light with stronger intensity, the purpose of increasing the brightness of the first color picture with low gray level is achieved, and therefore the brightness of the first color picture is higher, and the projection picture effect displayed by the projection system 100 is better.
It will be appreciated by those skilled in the art that other variations may be made in the design of the present invention without departing from the technical effects of the invention. Such variations, which are in accordance with the spirit of the invention, are intended to be included within the scope of the invention as claimed.
Claims (14)
1. A projection system, comprising:
the light emitting device can emit first color light, the period of emitting the first color light by the light emitting device at least comprises a first sub-period and a second sub-period, and the light intensity of the first color light emitted by the light emitting device in the first sub-period is different from that in the second sub-period;
A control device capable of acquiring input image data including a first color input gray scale value;
a light valve for image-modulating a first color of the image during a period in which the light emitting device emits the first color light in each frame image display period of the input image data,
wherein, for the input image data having a lower first color input gray scale value, the light valve modulates with the first color light of which the light emitting device emits a stronger light intensity in the first sub-period and the second sub-period as a light source.
2. The projection system of claim 1, wherein: the light emitting device includes:
a light source for emitting light;
the wavelength conversion device is arranged in a transmission path of light emitted by the light source, the wavelength conversion device can periodically emit light with different colors according to time sequence under the irradiation of the light source, the movement period of the wavelength conversion device is set to be one wavelength conversion device period, the period of emitting the first color light by the wavelength conversion device in one wavelength conversion device period at least comprises a first sub-period and a second sub-period, and the light intensity of the first color light emitted by the wavelength conversion device in the first sub-period is different from that of the light intensity of the first color light emitted by the wavelength conversion device in the second sub-period.
3. The projection system of claim 2, wherein: the light-emitting device further comprises a light source driving module for driving the light source, wherein the value of a first current for driving the light source is a first current value, and the first current value is set in the first sub-time period; the second current value of the light source driving module set in the second sub-time period for driving the light source is a second current value, and the first current value is different from the second current value.
4. A projection system according to claim 3, wherein: at least one of the first current value and the second current value is a fixed value.
5. A projection system according to claim 3, wherein: at least one of the first current value and the second current value is time-varying.
6. The projection system of claim 2, wherein: the light intensity of the first color light emitted by the wavelength conversion device in the first sub-period is larger than the light intensity of the first color light emitted by the wavelength conversion device in the second sub-period, and the first sub-period occurs before the second sub-period.
7. The projection system of any of claims 1-6, wherein: the first color is red, and the first color light is red.
8. The projection system of claim 1, wherein: the time for modulating the first color by the light valve comprises first color on-state time and first color off-state time, and the first color on-state time corresponds to the first color input gray scale value.
9. The projection system of claim 8, wherein: when the first color input gray scale value is set to be 1, the first color on state time of the light valve is set to be t, and when the first color input gray scale value is set to be Hx, the first color on state time of the light valve is set to be Hx multiplied by t, wherein Hx is an integer which is more than or equal to 0 and less than or equal to 255;
when the first color input gray scale value is set to be Hn, the first color on state time Hn multiplied by t of the first color input gray scale value Hn modulated by the light valve is equal to the first sub-time period, and when Hx is smaller than or equal to Hn, the first color input gray scale value Hx modulates first color light emitted by the light emitting device in the first sub-time period as a light source through the light valve; when the Hx is larger than the Hn, the n gray scales of the front section of the Hx are modulated by the first color light emitted by the first sub-time period as a light source, and the (x-n) gray scales of the rear section of the Hx are modulated by the light valve by the first color light emitted by the light emitting device in the second sub-time period as a light source.
10. The projection system of claim 8, wherein: for a certain pixel point in the first color image, the relative relation curve formed by the preset output light intensity of the pixel point and the actual output light intensity of the pixel comprises at least two segments, wherein in each segment, the preset output light intensity of the pixel and the actual output light intensity of the pixel are in linear relation, or
The relative relation curve formed by the preset output light intensity of the pixel point and the actual output light intensity of the pixel is a continuous curve which monotonically increases.
11. An image modulation method applied to a projection system, a light emitting device of the projection system capable of generating a first color light, the image modulation method comprising:
acquiring a frame of input image data signal, and generating a first color light modulation signal according to the input image data signal, wherein the first color light modulation signal corresponds to first color gray scale image data, and the first color gray scale image data comprises first color input gray scale values of a first color at each pixel point;
the first color light modulation signal is input to a light valve of the projection system, the light valve carries out image modulation on corresponding light emitted by a light emitting device of the projection system according to the first color light modulation signal, a period of emitting the first color light by the light emitting device at least comprises a first sub-period and a second sub-period, the light intensity of the first color light emitted by the light emitting device in the first sub-period is different from that of the first color light emitted by the light emitting device in the second sub-period, aiming at the input image data with lower first color input gray scale value, the light valve carries out modulation by taking the first color light with stronger light intensity emitted by the light emitting device in the first sub-period and the second sub-period as a light source.
12. The image modulation method of claim 11, wherein: the step of inputting the first color light modulation signal to a light valve of the projection system, wherein the light valve performs image modulation on corresponding light emitted by a light emitting device of the projection system according to the first color light modulation signal, further comprises: the first color light modulation signal is input to a light valve of the projection system, and when the light valve carries out image modulation on corresponding light emitted by a light emitting device of the projection system according to the modulation signal, the method further comprises detecting the light emitted by the light emitting device of the projection system, generating a synchronization signal, and inputting the synchronization signal and the light modulation signal to the light valve so that the modulation signal of the light valve is synchronous with the corresponding light emitted by the light emitting device.
13. The image modulation method of claim 11, wherein: the light intensity of the first color light emitted by the light emitting device in the first sub-period is larger than the light intensity of the first color light emitted by the light emitting device in the second sub-period, and the first sub-period occurs before the second sub-period.
14. An image modulation method applied to a projection system, a light emitting device of which is capable of emitting light of a first color at two different light intensities of the light of the first color, the image modulation method comprising:
Acquiring a frame of input image data signal, and generating a first color light modulation signal according to the input image data signal, wherein the first color light modulation signal corresponds to first color gray scale image data, and the first color gray scale image data comprises first color input gray scale values of a first color at each pixel point;
comparing a first color input gray level value of a pixel point with a preset gray level value, if the first color input gray level value is smaller than the preset gray level value, enabling the light-emitting device to emit light with higher first color light intensity when emitting first color light, and if the first color input gray level value is larger than or equal to the preset gray level value, enabling the light-emitting device to emit light with lower first color light intensity when emitting first color light;
the first color light modulation signal is input to a light valve of the projection system, the light emitting device is controlled to emit first color light according to the corresponding first color light intensity according to the comparison result, and the light valve carries out image modulation on the first color light emitted by the light emitting device of the projection system according to the first color light modulation signal.
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| CN112114478B (en) * | 2019-06-20 | 2022-02-08 | 青岛海信激光显示股份有限公司 | Projection display method and system |
| CN114305861B (en) * | 2022-03-14 | 2022-08-12 | 常州迅安科技股份有限公司 | Light valve color number control method of automatic light-changing filter |
| CN117930574A (en) * | 2024-03-21 | 2024-04-26 | 宜宾市极米光电有限公司 | Light source device and projection apparatus |
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| CN1784622A (en) * | 2003-05-09 | 2006-06-07 | 汤姆森特许公司 | Image projection system with imager provided with a colour wheel having a plurality of sub-sets of coloured segments, and corresponding projection appliance |
| CN101937164A (en) * | 2009-06-30 | 2011-01-05 | 卡西欧计算机株式会社 | Light supply apparatus and projector |
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| CN1784622A (en) * | 2003-05-09 | 2006-06-07 | 汤姆森特许公司 | Image projection system with imager provided with a colour wheel having a plurality of sub-sets of coloured segments, and corresponding projection appliance |
| CN101937164A (en) * | 2009-06-30 | 2011-01-05 | 卡西欧计算机株式会社 | Light supply apparatus and projector |
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