CN110873995B

CN110873995B - Projection method, projection system and projector

Info

Publication number: CN110873995B
Application number: CN201811014160.6A
Authority: CN
Inventors: 陈许; 吴凯; 吴超
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2018-08-31
Filing date: 2018-08-31
Publication date: 2021-07-23
Anticipated expiration: 2038-08-31
Also published as: CN110873995A

Abstract

The application discloses a projection method, a projection system and a projector. The projection system includes: a first digital mirror device DMD, a second DMD; the first DMD is used for outputting the illumination light beams from the light source, which are incident to the first DMD, in a partition mode according to the three-primary-color display time sequence and the light output quantity of each partition corresponding to the corresponding primary color; and the second DMD is used for modulating the light beam output by the first DMD in a subarea mode according to a driving signal generated based on the image to be projected, and the modulated light beam enters the projection lens for imaging.

Description

Projection method, projection system and projector

Technical Field

The present disclosure relates to the field of projection display, and in particular, to a projection method, a projection system, and a projector.

Background

Projectors are becoming more popular as computer graphic image output devices in teaching, demonstration, entertainment, work, and the like. A Digital Light Processing (DLP) projector is a projector adopting a special Light source modulation method, and because a full Digital reflection method is used, the DLP projector not only can make a projection display image more detailed, but also can effectively reduce the volume and weight of the projector, thereby being widely used.

DLP projectors use a Digital Micromirror Device (DMD) as a main component to implement Digital optical processing. The DMD is controlled by an image display driving signal to switch thousands of micromirrors back and forth between "on" and "off" states. The micro-mirror in the 'on' state reflects light into the lens, and accordingly generates a bright point on the projection screen; the "off" state of the micro-mirror will cause light to be reflected off the lens and absorbed as stray light, which in turn creates a dark spot on the projection screen. Therefore, the light quantity entering the lens is determined by the overturning angle and the overturning time length of each micro-reflector, and a projection display image is formed on the projection screen after the light quantity is reflected by all the micro-reflectors on the DMD and passes through the lens.

The existing three-primary-color ultra-short-focus laser projector has the problem of uneven chromaticity of a projection picture, so how to improve the chromaticity uniformity of the projection picture is a problem to be solved urgently.

Summary of the invention

The invention provides a projection method, a projection system and a projector, which are used for reducing the chromaticity difference of different areas in a projection picture.

In a first aspect, a projection system is provided, comprising: a first DMD, a second DMD; the first DMD is used for outputting the illumination light beams from the light source, which are incident to the first DMD, in a partition mode according to the three-primary-color display time sequence and the light output quantity of each partition corresponding to the corresponding primary color; and the second DMD is used for modulating the light beam output by the first DMD in a subarea mode according to a driving signal generated based on the image to be projected, and the modulated light beam enters the projection lens for imaging.

In one possible implementation, the first DMD is coupled to a first drive controller and the second DMD is coupled to a second drive controller. The first driving controller is used for determining the light output quantity respectively corresponding to the three primary colors in the corresponding subarea in the first DMD according to the brightness of different subareas in the projection image of the three primary colors in the projection area of the debugging image; according to the three-primary-color display time sequence, a driving signal is sent to the first DMD at the time corresponding to a primary color according to the light output quantity corresponding to the primary color in each partition in the first DMD; wherein a segment in the projected image of a primary color corresponds uniquely to a segment of the array of micro-mirrors in the first DMD. And the second driving controller is used for generating a driving signal acting on the second DMD according to the image to be projected and sending the generated driving signal to the second DMD.

In one possible implementation, the first driving controller includes: the image acquisition module is used for acquiring the projection images of the three basic colors of the debugging image in the projection area; the image analysis module is used for respectively partitioning the projection images of the three primary colors and determining the brightness of each partition; and respectively determining the deflection amount of the micro-mirror in each partition in the first DMD according to the brightness difference of different partitions aiming at the projected image of each basic color to obtain the deflection amount of the micro-mirror corresponding to each of the three basic colors; and the driving control module is used for sending a driving signal to the first DMD according to the deflection amount of the micro-mirror corresponding to the first basic color at the time corresponding to the first basic color according to the three-primary-color display time sequence, sending a driving signal to the first DMD according to the deflection amount of the micro-mirror corresponding to the second basic color at the time corresponding to the second basic color, and sending a driving signal to the first DMD according to the deflection amount of the micro-mirror corresponding to the third basic color at the time corresponding to the third basic color.

In a possible implementation manner, the image analysis module is specifically configured to: performing, for the projected image of each primary color: determining a minimum brightness among the brightness of all the partitions and a brightness difference between the brightness of other partitions and the minimum brightness; and determining the deflection amount of the micro-mirror in each partition according to the brightness difference of each partition in the other partitions, wherein the deflection amount of the micro-mirror in the partition corresponding to the minimum brightness enables the micro-mirror to be in an on state.

In a possible implementation manner, the image acquisition module is an image acquisition device, and is configured to acquire projection images of three primary colors.

In a possible implementation manner, the number of the partitions of the first DMD is less than or equal to the number of the micromirrors of the first DMD, and the number of the micromirrors included in one partition of the first DMD is less than or equal to the number of the pixel points of one partition in the first projected image.

In a possible implementation manner, the lighting system further includes an illumination light path, and the first DMD is arranged in the illumination light path or arranged in front of the illumination light path; the illumination light path is used for shaping the light beam emitted by the first DMD, and the shaped light beam meets the light spot size and the incident angle required by the incident of the second DMD.

In a second aspect, there is provided a projector including: a light source, a projection lens, and a projection system as described in any of the above first aspects; the light source provides illumination for the projection system, and the projection system modulates light source beams, outputs the light source beams to the projection lens for imaging, and projects the light source beams to a projection medium to form a projection picture.

In a possible implementation manner, the light source is a laser light source or a mixed light source of laser and fluorescence, and the laser light source includes a bicolor laser light source or a tricolor laser light source.

In a third aspect, there is provided a projection method implemented by the projection system of any of the first aspect or the projector of any of the second aspect, including: according to the three-primary-color display time sequence and the display time of a primary color, a driving signal is sent to the first DMD according to the light output quantity corresponding to the primary color in each partition of the first DMD to drive the micro-mirrors in the corresponding partitions, the driving signal is generated according to the image to be projected and sent to the second DMD so that the second DMD modulates the light beam of the primary color emitted from the first DMD partition, and the modulated light beam enters the projection lens to be imaged. Wherein the amount of light output corresponding to a key color in each section of the first DMD is determined based on the brightness of the different sections of the debug image in the projected image of the key color in the projection area.

In one possible implementation, determining the light output amount corresponding to a primary color in each of the partitions in the first DMD according to the brightness of different partitions in a projected image of the primary color in the projection area of the debug image includes: partitioning a projected image of one basic color of the debugging image in a projection area, and determining the brightness of each partition; and respectively determining the deflection amount of the micro-mirrors in each partition of the first DMD according to the brightness difference of different partitions, wherein the polarization amount of the micro-mirrors in one partition corresponds to the light output amount of the partition.

In a possible implementation manner, the separately determining the deflection amount of the micro mirrors in each of the sub-areas in the first DMD according to the brightness difference of the different sub-areas includes: determining a minimum brightness among the brightness of all the partitions and a brightness difference between the brightness of other partitions and the minimum brightness; and determining the deflection amount of the micro-mirrors in the subareas according to the brightness difference of each of the other subareas.

In the above embodiments of the present application, the projection system is provided with the first DMD for controlling the color map of the projection screen in addition to the second DMD for projecting an image. When projection is carried out, the first DMD can output the illumination light beams from the light source entering the first DMD in a partitioning mode according to the three-primary-color display time sequence and the light output quantity of each partition corresponding to the corresponding primary color, the second DMD can modulate the light beams output by the first DMD in the partitioning mode according to the driving signal generated based on the image to be projected, and the modulated light beams enter the projection lens for imaging. The first DMD can output the illumination light beams from the light source, which are incident to the first DMD, in the subareas according to the light output quantity of each subarea corresponding to the corresponding basic color according to the three-primary-color display time sequence, so that the brightness of different subareas in different primary-color display time can be controlled, the brightness of a projection picture tends to be uniform in the three-primary-color display time, and further, the chromaticity of the projection picture tends to be uniform.

Drawings

FIG. 1 is a schematic diagram of a DMD used in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a projection system according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of another projection system according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of another projection system according to an embodiment of the present disclosure;

FIG. 5 is a schematic view of a partition in an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a first control drive controller in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a projector according to an embodiment of the present application;

FIG. 8 is a schematic diagram illustrating a positional relationship between a three-primary-color laser light source including a light uniformizing element and a first DMD according to an embodiment of the present disclosure;

fig. 9 is a schematic flowchart of determining deflection amounts of micro mirrors corresponding to three primary colors according to an embodiment of the present application;

fig. 10 is a schematic projection flow chart provided in an embodiment of the present application.

Detailed Description

For the chromaticity uniformity of the projection picture, under an ideal condition, the tricolor brightness of each pixel point in a frame of projection image is the same. In order to improve the chromaticity uniformity of the projection picture, a DMD for controlling the light output amount is arranged between a light source and the DMD for projection display, so that the light output amount of a light beam incident to a rear-stage DMD (i.e., the DMD for projection display) is controlled by the DMD, and the three primary colors of the projection picture are adjusted in brightness, so that the chromaticity uniformity of the projection picture is realized.

The DMD is a bistable spatial light modulator composed of thousands of micro-mirrors (precision, micro-mirrors) formed by adding a rotating mechanism that can modulate the reflective surface to a standard Semiconductor process of Complementary Metal Oxide Semiconductor (CMOS). Data is loaded into a memory cell positioned below the micro-mirrors, the data electrostatically controls the deflection states of the micro-mirrors in a binary manner, and the angle and duration of deflection of each micro-mirror are independently controlled, thereby directing reflected light and modulating gray scale. Fig. 1 exemplarily shows deflection of two micromirrors on the DMD and a case of reflecting light. It can be seen that the micro mirrors 10 are deflected at different angles from the micro mirrors 20, and the micro mirrors 10 are deflected at angles by which the light emitted from the light source 30 can be reflected onto the light absorption unit 40, and the micro mirrors 20 are deflected at angles by which the light emitted from the light source 30 can be reflected onto the lens 50.

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

Referring to fig. 2, a schematic structural diagram of a projection system provided in an embodiment of the present application is shown. The projection system is applicable to short-focus projectors.

As shown, projection system 100a may include a first DMD 101 and a second DMD 102.

The first DMD 101 is configured to output the illumination light beam from the light source incident to the first DMD 101 in a divided manner according to the light output amount of each divided region corresponding to the corresponding primary color based on the three primary color display timing. And the second DMD 102 is used for modulating the light beam output by the first DMD 101 in a partitioning manner according to a driving signal generated based on the image to be projected, and the modulated light beam enters the projection lens for imaging.

It should be noted that fig. 2 only exemplarily illustrates the structure of the projection system, and in practical applications, the positions or the placement angles of the first DMD 101 and the second DMD 102 are not limited to those illustrated in fig. 2. In addition, in the path of the light beam propagating in the projection system, other devices may also be provided, which is not limited in this application.

Alternatively, based on projection system 100a shown in fig. 2, in some embodiments, in order to make the light beam incident on second DMD 102 conform to the spot size and incident angle required for second DMD 102 to be incident, an illumination light path 103 may be provided between first DMD 101 and second DMD 102, as shown in fig. 3. This configuration is suitable for the case where the resolution of first DMD 101 is greater than the resolution of second DMD 102, and in this case, the incident light spot of first DMD 101 is greater than the incident light spot of second DMD 102. Of course, this configuration is also applicable to the case where the resolution of first DMD 101 is less than or equal to the resolution of second DMD 102.

In the projection system 100b shown in fig. 3, an illumination optical path 103 is provided between the first DMD 101 and the second DMD 102 in addition to the projection system 100 a. The light beam emitted from the first DMD 101 enters the illumination light path 103, is shaped by the illumination light path 103, and is emitted to the second DMD 102 after being processed to conform to the spot size and the incident angle required by the incident of the second DMD 102.

The illumination light path 103 may be implemented by one or more optical devices, such as a collecting mirror, and the like, which is not limited to this embodiment.

Of course, the first DMD 101 may also be disposed within the illumination light path.

Alternatively, in some embodiments, a first driver controller is coupled to first DMD 101 and a second driver controller is coupled to second DMD 102 based on projection system 100a shown in fig. 2 or projection system 100b shown in fig. 3.

Fig. 4 schematically shows a projection system 100c, which further includes a first driving controller 104 and a second driving controller 105 on the basis of the projection system 100a shown in fig. 2.

As shown in fig. 4, in projection system 100c, first DMD 101 and second DMD 102 are provided in this order in the light beam propagation direction. First DMD 101 is coupled to first drive controller 104 and second DMD 102 is coupled to second drive controller 105.

Based on the projection system, the outgoing light beam of the light source is incident to the first DMD 101, the first DMD 101 reflects the incoming light beam to the second DMD 102, the second DMD 102 reflects the incoming light beam to the projection lens, and the projection lens projects the light beam on the projection screen.

The first driving controller 104 is configured to determine light output amounts respectively corresponding to three primary colors in corresponding partitions in the first DMD 101 according to luminances of different partitions in three primary color projection images of the debug image in the projection area; according to the three-primary-color display time sequence, a driving signal is sent to the first DMD 101 at the time corresponding to the first primary color according to the light output quantity corresponding to the first primary color in each area of the first DMD 101 so as to drive the micro mirrors in the corresponding subareas, and therefore the brightness of the projection picture of the first primary color is controlled at the first primary-color display time; sending a driving signal to the first DMD 101 according to the light output quantity corresponding to the second primary color in each area in the first DMD 101 at the time corresponding to the second primary color to drive the micro mirrors in the corresponding subarea, so as to control the brightness of the projection picture of the second primary color at the second primary color display time; and sending a driving signal to the first DMD 101 according to the light output amount corresponding to the third primary color in each area in the first DMD 101 at the time corresponding to the third primary color to drive the micromirrors in the corresponding sub-area, thereby controlling the brightness of the projected picture of the third primary color at the third primary color display time. Thus, the chromaticity of the projection picture can be controlled.

In particular, the amount of light output of each sub-area in the projection picture of the first primary color may be controlled by adjusting the amount of deflection of the micromirrors in each sub-area in the first DMD 101, so that the brightness of each sub-area in the projection picture of the first primary color tends to be equal, thereby reducing or even eliminating the brightness difference between the different sub-areas.

The deflection amount of the micro mirror may include one or more of a deflection angle of the micro mirror and a deflection time of the micro mirror (which may also be referred to as a deflection time period of the micro mirror). The reflection angle of the light incident on the surface of the micro-mirror can be changed by adjusting the deflection angle of the micro-mirror, so that the light is incident on the second DMD 102 or is not incident on the second DMD 102, and the brightness of the pixel point is changed. The more the number of flips of the micromirrors in the first DMD 101 is, the higher the brightness is, and vice versa. Taking the deflection angle of the micro-mirrors as an example, if the deflection angle of a certain micro-mirror in the first DMD is 12 degrees, the micro-mirror is in an on state, and light reflected by the micro-mirror can be incident to the second DMD, that is, the light output quantity of the emergent light is higher; if the deflection angle of a micro-mirror in the first DMD is-12 degrees, the micro-mirror is in the off state, and the light reflected by the micro-mirror cannot enter the second DMD but enters the light absorption unit, the light output quantity of the emergent light is zero. Taking the deflection times of the micro-reflector as an example, if the deflection times of the micro-reflector in unit time are higher, so that the total duration of the micro-reflector in the opening state is longer, the light output quantity of emergent light is higher; if the deflection times of the micro-mirror in unit time are lower, so that the total duration of the micro-mirror in the opening state is shorter, the light output quantity of the emergent light is lower.

The second driving controller 105 is configured to generate a driving signal acting on the second DMD 102 in accordance with an image to be projected, and send the generated driving signal to the second DMD 102.

The second DMD 102 modulates the light beam of the first keycolour emitted from the first DMD 101 to the second DMD 102 in accordance with the drive signal applied to the second DMD 102 at the first keycolour display time in accordance with the three-color display timing, modulates the light beam of the second keycolour emitted from the first DMD 101 to the second DMD 102 in accordance with the drive signal applied to the second DMD 102 at the second keycolour display time, and modulates the light beam of the third keycolour emitted from the first DMD 101 to the second DMD 104 in accordance with the drive signal applied to the second DMD 102 at the third keycolour display time.

According to the above-described embodiments of the present application, the projection system is provided with the first DMD for projection picture color map control in addition to the second DMD for image projection. The first driving controller connected with the first DMD can respectively determine light output quantities corresponding to the three primary colors in the corresponding partitions in the first DMD according to the brightness of different partitions in the projection image of the three primary colors, and when projection is performed, according to a display time sequence of the three primary colors, at the time corresponding to the first primary color, a driving signal is sent to the first DMD according to the light output quantity corresponding to the first primary color, and a driving signal acting on the second DMD is generated according to an image to be displayed and sent to the second DMD, so that the second DMD modulates the light beam of the first primary color emitted from the first DMD to the second DMD, and the brightness of each area in the projection picture tends to be uniform within the display time of the first primary color. Similar operations are performed at the display times of the second basic color and the third basic color. Because the brightness of the projection picture tends to be uniform in the display time of the three basic colors, the chromaticity of the projection picture tends to be uniform.

Based on the above projection system, before projection using the projection system, the first drive controller 104 analyzes the brightness of the projected images of the three primary colors (including the red projected image, the green projected image, and the blue projected image) from the projected images of the three primary colors acquired in the field, and generates the amount of deflection of each micromirror in the first DMD 101 corresponding to each of the three primary colors (including the amount of deflection of each micromirror in the first DMD 101 corresponding to each of the red, green, and blue colors) from the analysis result. When performing projection, the first driving controller 104 sends a driving signal to the first DMD 101 according to the deflection amount of each micro-mirror in the first DMD 101 corresponding to red when displaying red (that is, when the light beams incident to the first DMD 101 and the second DMD 102 are red light beams) according to the display timing sequence of the three primary colors, and the second driving controller 105 generates a driving signal according to the image to be projected and sends the driving signal to the second DMD 102 so as to modulate the red light beam emitted from the first DMD 101 to the second DMD 102; when displaying green (that is, when light beams incident to the first DMD 101 and the second DMD 102 are green light beams), a driving signal is sent to the first DMD 101 according to the deflection amount of each micro-mirror in the first DMD 101 corresponding to the green, and the second driving controller 105 generates a driving signal according to an image to be projected and sends the driving signal to the second DMD 102 to modulate the green light beam emitted from the first DMD 101 to the second DMD 102; when displaying blue (that is, when the light beams incident on the first DMD 101 and the second DMD 102 are blue light beams), a driving signal is sent to the first DMD 101 according to the deflection amount of each micromirror in the first DMD 101 corresponding to blue, and the second driving controller 105 generates a driving signal according to an image to be projected and sends the driving signal to the second DMD 102 to modulate the blue light beam emitted from the first DMD 101 to the second DMD 102. In this way, the micromirrors in the first DMD 101 are caused to perform state switching in accordance with the display timings of the three primary colors by the deflection amounts corresponding to the respective three primary colors. In this way, in the red display period, the uniformity of the red projection screen luminance can be achieved based on the state of the micromirrors in the first DMD 101 (the amount of deflection corresponding to red), in the green display period, the uniformity of the green projection screen luminance can be achieved based on the state of the micromirrors in the first DMD 101 (the amount of deflection corresponding to green), and in the blue display period, the uniformity of the blue projection screen luminance can be achieved based on the state of the micromirrors in the first DMD 101 (the amount of deflection corresponding to blue). Since the brightness of the three primary color projection pictures is uniform, the chromaticity of the projection picture with the mixed three primary colors is uniform.

The projection image of the debugging image for brightness control in the projection area can be obtained by shooting the projection image of the debugging image in the projection area on site. In practical application, when the chromaticity control is carried out, a red image can be projected in the projection area as a debugging image, so that a red field image of the projection area can be shot. The red field image is an image in which RGB of pixels in the image is (255,0, 0), that is, each pixel is displayed in red, and is referred to as a red field image. Based on a similar method, a green image (RGB of pixel point is (0,255,0,)) is projected as a debugging image to obtain a green field image, and a blue image (RGB of pixel point is (0,255,)) is projected as a debugging image to obtain a blue field image.

Of course, the debug image may also be a white field image. Since the white field image is obtained by projection based on the three primary color display timing, according to the three primary color display timing, a red field image whose primary color is red is captured when the red light beam is incident on the first DMD 101, a green field image whose primary color is green is captured when the green light beam is incident on the first DMD 101, and a blue field image whose primary color is blue is captured when the blue light beam is incident on the first DMD 101.

In order to facilitate brightness control, in the embodiment of the present application, the projection images of three primary colors may be separately partitioned.

In specific implementation, the three primary colors of projection images can be divided into 9 areas in a 3 × 3 array, 16 areas in a 4 × 4 array, or 36 areas in a 6 × 6 array as shown in fig. 5, respectively. The number of divisions and the division manner of the projected images of the three basic colors are kept consistent. In fig. 5, a shows the division of the red field image, b shows the division of the green field image, and c shows the division of the blue field image. The embodiment of the application does not limit the dividing mode and the number of the partitions.

According to the principle of reversible optical path, the partitions of the projected images of the three primary colors can be mapped to the partitions of the micro mirror array in the first DMD 101, wherein one partition in the projected images of the three primary colors uniquely corresponds to one partition of the micro mirror array in the first DMD 101. For example, if the red projected image is divided into 36 areas in a 6 × 6 array as shown in fig. 5, the micromirror array in the first DMD 101 also corresponds to 36 areas in a 6 × 6 array.

The maximum number of partitions of the projected image of the three primary colors is not greater than the number of micromirrors in the first DMD 101, that is, if the resolution of the first DMD 101 is M × N (i.e., the pixel array is M × N), the micromirror array in the first DMD 101 is M × N, each micromirror corresponds to one pixel point in the M × N pixel array, the partitions of the projected image of the three primary colors are at most M × N partitions, and each partition of the projected image is mapped to one micromirror of the micromirror array in the first DMD 101.

The more the number of the divided partitions is, the finer the chromaticity control of the projection picture is, and the more easily the adjusted picture chromaticity is uniform, so that in specific implementation, a proper partition mode and the number of the partitions can be determined according to the chromaticity uniformity index of the projection picture.

Optionally, based on the above projection system provided in this embodiment of the present application, in some embodiments, the resolution of first DMD 101 is less than or equal to the resolution of second DMD 102. The number of the partitions of the first DMD 101 is smaller than or equal to the number of the micromirrors in the first DMD 101, and the number of the micromirrors included in one partition of the first DMD 101 is smaller than or equal to the number of the pixel points of one partition in the first projected image.

If the resolution of the first DMD 101 is equal to the resolution of the second DMD 102, since the resolution of the second DMD 102 is the resolution of the projected image, the partition size of the micromirror array in the first DMD 101 is the same as the partition size of the projected area image (i.e., the number of pixel points is the same) during partitioning. When the partition size is set to the pixel level, that is, one micromirror in the first DMD 101 corresponds to one pixel in the image of the projection area (one pixel forms one partition), the brightness control can be performed for each pixel in the projection image, so that higher brightness control accuracy can be achieved.

If the resolution of the first DMD 101 is smaller than the resolution of the second DMD 102, the partition size of the micromirror array in the first DMD 101 is smaller than the partition size of the image of the projection area during the partitioning (i.e., the number of pixels in one partition of the former is smaller than the number of pixels in the latter). The partition size is set to a pixel point level, that is, one micro mirror in the first DMD 101 corresponds to a plurality of pixel points in the projection area image (the plurality of pixel points form one partition in the projection area image), so that the DMD with lower resolution can be used to control the brightness of the projection picture with higher resolution, and the cost of chromaticity control can be reduced.

The following expression may represent the resolution of the first DMD and the second DMD versus the partition size:

wherein a is a constraint coefficient, is a ratio of resolutions of the first DMD and the second DMD, and takes an integer greater than or equal to 1; k is the magnification of the projection lens; s1 is the imaging area of second DMD 102; s2 is the area of the actual projected image; m is the number of pixel points in a partition of the micro-mirror matrix of the first DMD; n is the number of pixel points in a partition in the projection area image.

When a is 1, the number of pixel points in the partition of the projection area image is equal to the number of pixel points in the partition of the micro-reflector matrix of the first DMD;

when a is more than 1, the number of pixel points in the partition of the micro-reflector matrix of the first DMD is larger than the number of pixel points in the partition in the projection area image.

For example, the first DMD 101 may select a DMD chip with a resolution of 720P, 1080P, or 4K, the higher the resolution is, the higher the requirement for the accuracy of the chromaticity control is, for the first DMD 102 with a resolution of 1080P (resolution of 1920 × 1080), the chromaticity control for each pixel point may be implemented, that is, the projection image of the debug image in the three basic colors in the projection area and the micromirror array in the first DMD 101 are divided into 1920 × 1080 partitions, so as to achieve the chromaticity control at the pixel point level. Since the higher the resolution of the DMD is, the larger the effective area of the DMD (i.e., the effective photosensitive area for the partition adjustment) is, in consideration of the volume requirement and the cost of the projector in practical application, the first DMD 101 with a smaller resolution may be used to control the chromaticity of the projection picture with a higher resolution, for example, the first DMD 101 selects a DMD chip with a resolution of 720P to realize the chromaticity control of the projection picture with a resolution of 1280 × 720P.

Alternatively, based on the projection system described above, in some embodiments, the structure of the first driving controller 104 may be as shown in fig. 6.

Fig. 6 is a schematic structural diagram of a first driving controller in the embodiment of the present application. The first drive controller 104 may include: an image acquisition module 1041, an image analysis module 1042, and a drive control module 1043.

The image acquiring module 1041 is configured to acquire projection images (such as a red field image, a green field image, and a blue field image) of three basic colors of the debugging image in the projection area; the image analysis module 1042 is configured to partition the projection images of the three primary colors, and determine the brightness of each partition; respectively determining the deflection amount of the micro-mirrors in each partition in the first DMD 101 according to the brightness difference of different partitions aiming at each primary color projection image to obtain the deflection amount of the micro-mirrors corresponding to the three primary colors; the driving control module 1043 is configured to send a driving signal to the first DMD 101 according to the deflection amount of the micro mirror corresponding to the first basic color at a time corresponding to the first basic color according to the three-primary color display timing sequence, send a driving signal to the first DMD 101 according to the deflection amount of the micro mirror corresponding to the second basic color at a time corresponding to the second basic color, and send a driving signal to the first DMD 101 according to the deflection amount of the micro mirror corresponding to the third basic color at a time corresponding to the third basic color.

Optionally, based on the first driving controller 104 shown in fig. 6, in some embodiments, the image acquisition module 1041 is an image acquisition device for acquiring a projection image of the debugging image. For example, the image capturing device may be a camera (e.g., a high resolution camera) disposed on the projector, and when performing brightness control, images of three primary color projection areas of the projection area may be captured by the camera first.

For another example, the image capturing device may also be an image sensor disposed in the projector, and the image sensor can capture the light beam incident to the projection lens and obtain the three primary color projection area images through digital conversion. Specifically, the debugging image is a white field image, according to a three-primary-color display time sequence, a red field image can be obtained by shooting through a camera or collecting through an image sensor when a red light beam enters the first DMD 101, a green field image can be obtained by shooting through the camera or collecting through the image sensor when a green light beam enters the first DMD 101, and a blue field image can be obtained by shooting through the camera or collecting through the image sensor when a blue light beam enters the first DMD 101.

Alternatively, based on the first driving controller 104 shown in fig. 6, in some embodiments, the image acquisition module 1041 may acquire a projection image acquired by an image acquisition device, such as a projection image receiving three primary colors acquired by a camera or a sensor.

Alternatively, based on the first driving controller 104 shown in fig. 6, in some embodiments, the image analysis module 1042 is configured to partition the projection images of the three basic colors according to a preset number of partitions and a partition manner, and determine the brightness of each partition in the projection image of each basic color.

The description of the image partition processing of the image analysis module 1042 can be referred to the foregoing embodiments, and is not repeated here.

Optionally, when determining the brightness of the partition, the image analysis module 1042 may calculate, for each partition in the projected image of each basic color, a sum of the brightness of all the pixel points in the partition according to the brightness of the pixel points in the partition (each pixel point has brightness information and color information), and use the sum of the brightness of all the pixel points in the partition as the brightness of the partition, or use an average brightness of all the pixel points in the partition as the brightness of the partition, or use the brightness of the pixel point at the center position in the partition as the brightness of the partition.

Alternatively, based on the first driving controller 104 shown in fig. 6, in some embodiments, the process of determining the deflection amount of the micro mirrors in each partition of the first DMD 101 by the image analysis module 1042 according to the brightness difference of the different partitions may specifically include: the minimum brightness among the brightness of all the partitions and the brightness difference between the brightness of the other partitions and the minimum brightness are determined, and the deflection amount of the micro mirrors in the partitions is determined according to the brightness difference of each of the other partitions, so that the light output amounts of the outgoing light beams of all the partitions in the first DMD 101 tend to be the same. The amount of deflection of the micromirror in the partition corresponding to the minimum brightness makes the micromirror in an on state (for example, the deflection angle is 12 degrees), so that the amount of deflection of the micromirror corresponding to the partition with higher brightness in the projected image of the debug image can be adjusted to make the micromirror in an off state (for example, the deflection angle is-12 degrees), thereby reducing the brightness of other partitions except the partition corresponding to the minimum brightness, and making the brightness of each partition in the projected image of the debug image uniform.

Taking 36 partitions shown in fig. 5 as an example, the process of determining the deflection amount of each micro mirror in each partition in the first DMD 101 according to the brightness difference of different partitions may specifically include: aiming at the red field image, respectively calculating the brightness sum L of all pixel points in each partition in 36 partitions in the red field image_i. The division with the highest luminance calculated by the luminance of 36 divisions is assumed to be 15 divisions and is denoted as L_maxThe partition with the lowest brightness is a 1-region and is marked as L_min. The deflection angle of the micromirrors in the region corresponding to region 1 in the first DMD 101 is set to 12 degrees (on state). Calculating the brightness L of each region and 1 region_minFor the sub-areas with the brightness difference larger than the set threshold value in the 2-36 areas, the deflection angle of the micro-mirrors in the corresponding sub-areas in the first DMD 101 is adjusted to-12 degrees (off state), so as to reduce the light output of the high-brightness sub-areas, and make the brightness of the 36 sub-areas in the red-field image tend to L_minSo as to achieve the brightness uniformity of the whole display picture. The brightness of each segment and the difference from the minimum brightness can be determined in the above manner for the green field image and the blue field image, and thus the amount of deflection of the micromirror.

The projection system provided by the above embodiment of the present application can be applied to a projector.

Referring to fig. 7, a schematic structural diagram of a projector according to an embodiment of the present application is provided.

As shown in fig. 7, the projector 200 may include a light source 106, a projection lens 107, and a projection system provided in the embodiment of the present application. The projection system may be the projection system provided in any of the above embodiments, fig. 7 illustrates a projection system 100a, and the structure shown in fig. 7 does not limit the present application.

The light source 106 provides illumination for the projection system 100a, and the projection system 100a modulates the light source beam, outputs the modulated light source beam to the projection lens 107 for imaging, and projects the modulated light source beam onto the projection medium 108 to form a projection picture.

Alternatively, based on the projector shown in fig. 7, in some embodiments, the light source 106 is a laser light source or a mixed light source of laser and fluorescent light, the laser light source may be a three-primary-color laser light source, and the mixed light source of laser and fluorescent light may be a mixed light source of laser of one primary color and fluorescent light of two primary colors, or may be a mixed light source of two-primary-color laser light and fluorescent light of one primary color.

Alternatively, based on the projector shown in fig. 7, in some embodiments, a light uniformizing member may be disposed in the light source 106. Further, if the light source 106 is a two-color laser light source or a three-color laser light source, a light combiner is further provided before the light uniformizing part. Further, if the light source 106 is a mixed light source of laser light and fluorescent light, a fluorescent wheel is also provided. The light source 106 includes a light homogenizing member, which may be a light rod or a device having a light homogenizing function, such as a fly-eye lens. Alternatively, the first DMD 101 may be disposed at the light exit position of the light unifying member in the light source 106.

Fig. 8 exemplarily shows a positional relationship between the three-primary-color laser light source 106 including the light uniformizing section and the first DMD 101. As shown in the figure, laser beams emitted by the blue laser 1061, the green laser 1062, and the red laser 1063 in the three-primary-color laser light source 106 pass through the light combiner 1064 and the light, are converged by the converging lens 1065, and then enter the light rod 1066, and are emitted from the light outlet of the light rod 1066 to the first DMD 101 located at the light outlet after being homogenized by the light rod 1066.

Referring to fig. 9, a schematic diagram of a process for determining deflection amounts of micro mirrors corresponding to three primary colors according to an embodiment of the present application is shown, where the process can be implemented based on the structure of the projector provided in the foregoing embodiment. As shown, the process may include:

s701: and acquiring a projection image of the first primary color of the debugging image in the projection area, and determining the deflection amount of the micro-mirrors respectively corresponding to the first primary color in the corresponding subarea in the first DMD according to the brightness of different subareas in the projection area image of the first primary color.

The step of acquiring the projection image may be implemented by an image acquisition module in the first driving controller in the projector, for example, the projection image of the first primary color may be acquired by the image acquisition module, and specific implementation procedures may be referred to the foregoing embodiments and will not be described in detail here.

The step of determining the deflection amount of the micro-mirror can be realized by an image analysis module in the first driving controller in the projector. For example, the image analysis module may partition the projected image of the first primary color, and determine the brightness of each partition; the deflection amount of the micro mirrors in each of the segments in the first DMD is determined separately based on the brightness difference of the different segments.

Alternatively, the process of separately determining the deflection amount of the micromirrors in each of the partitions in the first DMD may include: determining a minimum brightness among the brightness of all the partitions and a brightness difference between the brightness of other partitions and the minimum brightness; and determining the deflection amount of the micro-mirrors in the subareas according to the brightness difference of each of the other subareas.

S702: and acquiring a projection image of the second primary color of the debugging image in the projection area, and determining the deflection amount of the micro-mirrors respectively corresponding to the second primary color in the corresponding subarea in the first DMD according to the brightness of different subareas in the projection area image of the second primary color.

S703: and acquiring a projection image of the third primary color of the debugging image in the projection area, and determining the deflection amount of the micro-mirrors respectively corresponding to the third primary color in the corresponding subarea in the first DMD according to the brightness of different subareas in the projection area image of the third primary color.

The above process may be performed before projection using the projector, i.e., in a commissioning phase of the projector. The deflection amounts of the micromirrors in the first DMD 101 corresponding to the three primary colors (or the light output amounts of the corresponding sub-areas in the first DMD 101 corresponding to the three primary colors) obtained by the above procedure can be stored in the memory of the projector for use in projection.

Referring to fig. 10, a schematic diagram of a projection process provided in an embodiment of the present application is shown, where the process can be implemented based on the structure of the projector provided in the foregoing embodiment. When the projection is carried out on the image to be projected, according to the three-primary-color display time sequence, the following steps can be executed:

s801: at the time corresponding to the first basic color, the first driving controller sends driving signals to the first DMD according to the light output quantity corresponding to the first basic color in each partition of the first DMD so as to drive the micro mirrors in the corresponding partition; the second driving controller generates a driving signal according to the image to be projected and sends the driving signal to the second DMD so that the second DMD modulates the light beam of the first basic color emitted from the first DMD to the second DMD.

S802: at the time corresponding to the second basic color, the first driving controller sends driving signals to the first DMD according to the light output quantity corresponding to the second basic color in each partition of the first DMD so as to drive the micro mirrors in the corresponding partitions; the second driving controller generates a driving signal according to the image to be projected and sends the driving signal to the second DMD so that the second DMD modulates the light beam of the second basic color emitted from the first DMD to the second DMD.

S803: at the time corresponding to the third basic color, the first driving controller sends driving signals to the first DMD according to the light output quantity corresponding to the third basic color in each partition of the first DMD so as to drive the micro mirrors in the corresponding partitions; the second driving controller generates a driving signal according to the image to be projected and sends the driving signal to the second DMD so that the second DMD modulates the light beam of the third basic color emitted from the first DMD to the second DMD.

According to the process shown in fig. 10, in a specific implementation, according to a three-primary-color display sequence, when switching to display red (a red light beam enters the first DMD and the second DMD), in S801, the first driving controller generates a driving signal of the first DMD according to a deflection amount of a micro-mirror corresponding to the red color and sends the driving signal to the first DMD, and the second driving controller generates a driving signal according to an image to be projected and sends the driving signal to the second DMD so that the second DMD modulates the red light beam emitted from the first DMD to the second DMD; when the display is switched to green (the green light beam enters the first DMD and the second DMD), in S801, the first driving controller generates a driving signal of the first DMD according to the deflection amount of the micromirror corresponding to the green and sends the driving signal to the first DMD, and the second driving controller generates a driving signal according to the image to be projected and sends the driving signal to the second DMD so that the second DMD modulates the green light beam emitted from the first DMD to the second DMD; when the display is switched to blue (the blue light beam enters the first DMD and the second DMD), in S801, the first drive controller generates a drive signal for the first DMD according to the deflection amount of the micromirror corresponding to blue and sends the drive signal to the first DMD, and the second drive controller generates a drive signal according to the image to be projected and sends the drive signal to the second DMD so that the second DMD modulates the blue light beam emitted from the first DMD to the second DMD.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A projection system, comprising: the digital mirror device comprises a first digital mirror device DMD and a second digital mirror device DMD, wherein the first DMD is connected with a first driving controller, and the second DMD is connected with a second driving controller;

the first driving controller is used for determining the light output quantity respectively corresponding to the three basic colors in the corresponding subareas in the first DMD according to the brightness of different subareas in the projection images of the three basic colors in the projection area of the debugging image, so that the brightness of each subarea in the projection image of the same basic color tends to be equal; according to the three-primary-color display time sequence, a driving signal is sent to the first DMD at the time corresponding to a primary color according to the light output quantity corresponding to the primary color in each partition in the first DMD; wherein a segment in the projected image of a primary color corresponds uniquely to a segment of the array of micro-mirrors in the first DMD;

the first DMD is configured to output the illumination light beam from the light source, which is incident to the first DMD, in a divisional manner according to the light output amount of each division corresponding to the corresponding basic color based on a three-primary-color display timing sequence according to the driving signal sent by the first driving controller;

the second driving controller is used for generating a driving signal acting on the second DMD according to the image to be projected and sending the generated driving signal to the second DMD;

and the second DMD is used for modulating the light beam output by the first DMD in a subarea mode according to the driving signal sent by the second driving controller, and the modulated light beam enters the projection lens for imaging.

2. The projection system of claim 1, wherein the first drive controller comprises:

the image acquisition module is used for acquiring the projection images of the three basic colors of the debugging image in the projection area;

the image analysis module is used for respectively partitioning the projection images of the three basic colors and determining the brightness of each partition; and respectively determining the deflection amount of the micro-mirror in each partition in the first DMD according to the brightness difference of different partitions aiming at the projected image of each basic color to obtain the deflection amount of the micro-mirror corresponding to each of the three basic colors;

and the driving control module is used for sending a driving signal to the first DMD according to the deflection amount of the micro-mirror corresponding to the first basic color at the time corresponding to the first basic color according to the three-primary-color display time sequence, sending a driving signal to the first DMD according to the deflection amount of the micro-mirror corresponding to the second basic color at the time corresponding to the second basic color, and sending a driving signal to the first DMD according to the deflection amount of the micro-mirror corresponding to the third basic color at the time corresponding to the third basic color.

3. The projection system of claim 2, wherein the image analysis module is specifically configured to: performing, for the projected image of each primary color:

determining a minimum brightness among the brightness of all the partitions and a brightness difference between the brightness of other partitions and the minimum brightness;

and determining the deflection amount of the micro-mirror in each partition according to the brightness difference of each partition in the other partitions, wherein the deflection amount of the micro-mirror in the partition corresponding to the minimum brightness enables the micro-mirror to be in an on state.

4. The projection system of claim 2, wherein the image acquisition module is an image acquisition device for acquiring projection images of three primary colors.

5. The projection system of claim 1, wherein the number of segments of the first DMD is less than or equal to the number of micromirrors of the first DMD, and the number of micromirrors included in one segment of the first DMD is less than or equal to the number of pixel points of one segment in a projected image of any one base color.

6. The projection system of claim 1, further comprising an illumination light path, the first DMD disposed in or before the illumination light path;

the illumination light path is used for shaping the light beam emitted by the first DMD, and the shaped light beam meets the light spot size and the incident angle required by the incident of the second DMD.

7. A projector, characterized by comprising: a light source, a projection lens, and the projection system of any one of claims 1 to 6;

the light source provides illumination for the projection system, and the projection system modulates light source beams, outputs the light source beams to the projection lens for imaging, and projects the light source beams to a projection medium to form a projection picture.

8. The projection system of claim 7, wherein the light source is a laser light source or a hybrid laser and phosphor light source, the laser light source comprising a two-color laser light source or a three-primary color laser light source.

9. A projection method implemented based on the projection system of any one of claims 1 to 6, comprising:

according to a three-primary-color display time sequence and the display time of a primary color, sending a driving signal to a first DMD according to the light output quantity corresponding to the primary color in each partition of the first DMD to drive a micro mirror in the corresponding partition, generating a driving signal according to a to-be-projected image and sending the driving signal to a second DMD so that the second DMD modulates the light beam of the primary color emitted from the first DMD partition, and enabling the modulated light beam to enter a projection lens for imaging;

wherein the amount of light output corresponding to a key color in each section of the first DMD is determined based on the brightness of the different sections of the debug image in the projected image of the key color in the projection area.

10. The method of claim 9, wherein determining the amount of light output for a key color in each segment of the first DMD based on the brightness of different segments of a projected image of the key color in the projected area from the debug image comprises:

partitioning a projected image of one basic color of the debugging image in a projection area, and determining the brightness of each partition;

and respectively determining the deflection amount of the micro-mirrors in each partition of the first DMD according to the brightness difference of different partitions, wherein the polarization amount of the micro-mirrors in one partition corresponds to the light output amount of the partition.

11. The method of claim 10, wherein the separately determining the amount of deflection of the micromirrors in each of the segments in the first DMD based on the differences in brightness of the different segments comprises:

and determining the deflection amount of the micro-mirrors in the subareas according to the brightness difference of each of the other subareas.