JP6364609B2 - Projection-type image display device and image signal generation device - Google Patents

Description

  The present disclosure relates to a projection type image display apparatus such as a projector.

  Conventionally, an optical path changing unit and a drive unit that moves the optical path changing unit are provided between the rear lens group and the front lens group, and the optical path changing unit moves the optical path of the image light in a direction perpendicular to the optical axis. A projection type image display apparatus for shifting is known.

  Thereby, this projection type image display apparatus can provide an image having a resolution higher than the resolution of the image displayed by the light valve without deterioration in quality (for example, Patent Document 1).

JP 2005-227334 A

  Provided is a projection type image display device capable of optimal display regardless of the type of input image signal.

  The projection-type image display device of the present disclosure receives either a first image signal that is a high-resolution image signal or a second image signal that is a lower-resolution image signal than the first image signal and that has been subjected to pixel shift processing. An image signal input unit that is input as an image signal, a signal determination unit that determines whether the input image signal input to the image signal input unit is a first image signal or a second image signal, and an input to the image signal input unit A re-sampling unit that generates a re-sampled image signal that has the same resolution as the second image signal and is displayed at the same frame rate by re-sampling the first image signal of one frame at different sample positions; Based on the determination result of the signal determination unit, the image signal processing unit that performs any one of the process of generating the resampled image signal in the resampling unit and the process of outputting the second image signal, A light modulation element that generates image light obtained by modulating light from a source based on a resampled image signal or a second image signal obtained from the image signal processing unit; and image light emitted from the light modulation element in units of frames And an image shift unit for pixel shift.

  According to the present disclosure, in a projection image display apparatus capable of projecting a high-resolution image, optimal display is possible regardless of the type of input image signal.

The figure which shows an example of the optical structure of a projection type image display apparatus The block diagram which shows the image display system used by embodiment Schematic of an optical element driving device used in the embodiment The figure which shows the components used with the optical element drive The figure for explaining the principle of the optical path change by the parallel plate glass Plan view of parallel flat glass used in the embodiment The figure for demonstrating the motion of the parallel plate glass used in embodiment Schematic diagram of the base image signal that is the base of the projected image The figure which shows the sub-frame image for 2 times dense images produced | generated from a base image signal The figure which shows the state which shifted the sub-frame image so that it may become a 2 times dense image. The figure which shows the sub-frame image for 4 times dense images produced | generated from a base image signal The figure which shows the state which shifted the sub-frame image so that it may become a 4 times dense image. Block diagram of control to switch processing according to input signal The figure which shows the specific example of the control which switches a process by an input signal The figure which shows another specific example of the control which switches a process with an input signal Block diagram showing the PC system The figure which shows the technique of image generation with PC The figure which shows the production | generation method of the 1st sub-frame image by PC The figure which shows the production | generation method of the 2nd sub-frame image by PC Block diagram when configuring separate systems based on input image signals

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

Hereinafter, embodiments will be described with reference to FIGS.
[Optical configuration of projector]
An outline of the projector 100 will be described with reference to a schematic diagram of an optical configuration in FIG.

  The projector 100 includes a light source 130 including an arc tube 110 and a reflector 120 that reflects white light emitted from the arc tube 110. The arc tube 110 emits a white light beam including red light, green light, and blue light having different wavelength ranges. The arc tube 110 is composed of, for example, an ultrahigh pressure mercury lamp or a metal halide lamp. The reflector 120 reflects the light beam emitted from the arc tube 110 arranged at one focal position, and emits it as parallel light forward.

  White light from the light source 130 is input to the illumination optical system. The illumination optical system includes a lens 160, a rod 170, a lens 180, and a mirror 190. The illumination optical system guides the light beam emitted from the light source 130 to digital mirror devices (hereinafter referred to as DMD) 240, 250, and 260. The rod 170 is a columnar glass member that totally reflects light inside. The light beam emitted from the light source 130 is reflected in the rod 170 a plurality of times. Thereby, the light intensity distribution on the exit surface of the rod 170 becomes substantially uniform.

  The lens 180 is a relay lens that forms an image of the light beam on the exit surface of the rod 170 on the DMDs 240, 250, and 260. The mirror 190 reflects the light beam that has passed through the lens 180. The reflected light beam enters the field lens 200. The field lens 200 is a lens that converts incident light into a substantially parallel light beam. The light beam that has passed through the field lens 200 enters the total reflection prism.

  The total reflection prism includes a prism 270 and a prism 280. An air layer 210 exists on the proximity surface between the prism 270 and the prism 280. The air layer 210 is a thin air layer. The air layer 210 totally reflects a light beam incident at an angle greater than the critical angle. The totally reflected light beam enters the color prism.

  The color prism includes a prism 221, a prism 231 and a prism 290. A dichroic film 220 that reflects blue light is provided on the adjacent surface of the prism 221 and the prism 231. Further, a dichroic film 230 that reflects red light is provided on the adjacent surface of the prism 231 and the prism 290. DMDs 240, 250, and 260 are disposed in the color prism.

  DMD 240, DMD 250 and DMD 260 have 1920 × 1080 micromirrors. DMD 240, DMD 250, and DMD 260 deflect each micromirror according to an image signal. Thereby, DMD 240, DMD 250, and DMD 260 divide the light incident on DMD into light that is incident on projection optical system 300 and light that is reflected outside the effective range of projection optical system 300 according to the image signal. Modulate. Note that green light is incident on the DMD 240. Red light is incident on the DMD 250. Blue light is incident on the DMD 260.

  Of the light beams reflected by DMD 240, DMD 250, and DMD 260, the light beams that enter projection optical system 300 are combined by a color prism. The synthesized light beam enters the total reflection prism. The light beam incident on the total reflection prism enters the air layer 210 at a critical angle or less. Accordingly, this light beam passes through the air layer 210 and enters the projection optical system 300.

  The projection optical system 300 is an optical system for expanding an incident light beam. The projection optical system 300 has a focus function and a zoom function, and projects an image on the projection surface by projecting image light from the DMD onto the projection surface.

The projector 100 includes a parallel plate glass 400 as an optical element that is disposed in a plane perpendicular to the optical axis of the projection optical system and can operate as described below. The projector 100 operates the parallel flat glass 400 to shift the display position on the projection plane (screen) of the pixels constituting the image generated by the DMD at intervals equal to or less than the pixel pitch. Thereby, the projector 100 can project a high-resolution image.
[Configuration between prism and projection lens]
Next, an optical element driving device for driving the parallel flat glass 400 disposed between the prism block including the total reflection prism and the color prism and the projection optical system 300 will be described.

  FIG. 2 is a block diagram showing an overall circuit configuration of the optical element driving apparatus according to the present embodiment, and FIG. 3 is a diagram showing a schematic configuration of the optical element driving apparatus driven by the circuit of FIG. The circuit configuration shown in FIG. 2 is provided in the projector except for an external device such as a personal computer (PC) connected thereto.

  In the present embodiment, a plane circular parallel flat glass 400 is used as the optical element. The end portions of the parallel flat glass 400 are connected to the movable portions 407a, 407b, 407c, and 407d of the four actuators A401a, B401b, actuator C401c, and actuator D401d by connecting members 406a, 406b, 406c, and 406d, respectively.

  In this embodiment, a voice coil motor (VCM) is used as the actuator 401. FIG. 4 shows an example of the structure of the VCM, in which a permanent magnet having different magnetic poles (N-pole permanent magnet 4012 and S-pole permanent magnet 4013) is separated from the inside of a U-shaped yoke 4011 by a certain distance. The movable part 407 is arranged between the permanent magnets 4012 and 4013 arranged so as to face each other.

  A guide window 4070 is provided in the movable portion 407, a yoke 4011 is inserted into the guide window 4070, and a coil 4014 provided in the movable portion 407 is disposed between the permanent magnets 4012 and 4013 arranged to face each other. Is done. When a drive signal current is passed through the coil 4014, the movable portion 407 moves in the uniaxial direction of the arrow. The moving amount of the movable portion 407 moves from the reference position in the positive direction or the negative direction according to the magnitude of the signal current flowing in the coil 4014. The amount of movement of the movable part 407 is detected by detecting the position sensor 402 attached to the movable part 407 by the position detection circuit 403 shown in FIG. There is a slight gap between the movable part 407 to which the coil 4014 is attached and the permanent magnets 4012 and 4013. Therefore, even if a force in a direction perpendicular to the uniaxial direction driven by the drive signal current is applied to the movable portion 407, the movable portion 407 can be displaced by an allowable distance by a slight gap, and the movable portion 407 can tilt. it can.

  The connecting member 406 to which the movable portion 407 of the actuator 401 is coupled is formed at the center of each side on the A-C axis and the B-D axis that are orthogonal to each other at the plane center O of the parallel plate glass 400 as shown in FIG. The ends EA, EB, EC, and ED are connected.

  The four actuators A 401 a, actuator B 401 b, actuator C 401 c, and actuator D 401 d are driven by drive circuits 404 a, 404 b, 404 c, and 404 d controlled by a control signal from one microcomputer 405. The actuators A401a to D401d are driven by the drive signal currents from the drive circuits 404a to 404d so that the movable portions 407a to 407d advance and retreat in one axis direction. The positions of the movable parts 407a to 407d are detected by the position detection circuits 403a to 403d by the position sensors 402a to 402d provided therein. The detection outputs of the position detection circuits 403a to 403d are input to the microcomputer 405. The microcomputer 405 constantly monitors the positions of the movable parts 407a to 407d of the actuators A401a to D401d based on the detection signals, and the actuators A401a. -Servo control of the actuator D401d is performed.

  The sub-frame image signal obtained after the input image signal is processed by the image signal processing unit 410 is input to the microcomputer 405, and a synchronization signal to be supplied to the drive circuits 404a to 404d is generated based on this image signal, and DMD A DMD driving signal and a synchronization signal for controlling the driving unit 411 are generated.

  As for the movement amounts of the movable portions 407a to 407d of the actuators A to D, a signal indicating the adjustment amount is input to the microcomputer 405 by operating the shift amount operation unit 412, and the microcomputer 405 controls the drive circuits 404a to 404d. It is adjusted by doing. The shift amount operation unit 412 may be, for example, an operation key provided in the main body of the projector 100, or may be a key assigned to a remote controller that operates the projector 100.

  The operation of the optical element driving apparatus configured as described above will be described below.

  As shown in FIG. 5, when the plane of the parallel plate glass 400 is orthogonal to the input light beam Li, the input light beam Li travels straight without being refracted at the interface between the parallel plate glass 400 and the air. The input light beam passes through the parallel flat glass 400 without being refracted, and also at the interface exiting to the air, since the parallel flat glass 400 is a parallel plane, the light beam and the interface are orthogonal to each other. To do. For this reason, when the input light beam is image light, movement (shift) of the image does not occur.

  On the other hand, when the parallel flat glass 400 is not orthogonal to the input light as shown by the broken line in FIG. 5, the input light is refracted at the interface between the parallel flat glass 400 and the air. The input light beam Li is refracted and incident on the parallel flat glass plate 400, and then passes through the parallel flat glass plate 400 and exits to the air. Since the parallel flat glass plate 400 is a parallel flat surface, the light beam and the interface are not orthogonal. Therefore it is refracted.

  Since the angle of refraction when entering the parallel plate glass 400 and the angle of refraction when exiting from the parallel plate glass 400 are equal, if the input light beam Li is image light, the image light of the output light Lo is parallel plate glass. Translate in the direction of the tilt. As a result, the display position of the image output from the parallel flat glass 400 and projected is moved (shifted).

  Utilizing such a principle, glass end portions EA and EC on the A-C and B-D axes perpendicular to each other passing through the center O of the parallel flat glass 400 used in the present embodiment shown in FIG. , And EB and ED are slidably connected to the movable part by a connecting member of each actuator. Then, by driving the actuator, while maintaining the position of the center O constant, for example, the A-C axis shown in FIG. 7 is moved up the end EA by a predetermined amount about the B-D axis as the rotation axis center. The end EC is moved downward by a predetermined amount, the BD axis is moved downward by a predetermined amount about the A-C axis as the rotation axis, and the end ED is moved upward by a predetermined amount. Let Thereby, the optical path of the image light incident on the glass plate is changed, and the pixel is displayed at a predetermined position. From this state, by similarly controlling each end in the vertical direction, a pixel shift that moves the display position of the pixel can be performed.

The image signal processing unit 410 generates two or four sub-frame image signals corresponding to the movement of the projection position by the optical element driving device for each frame of the input image signal. Note that the number of pixels of the sub-frame image signal is the same as the number of corresponding pixels of the DMDs 240, 250, and 260.
[Double dense image output operation]
The microcomputer 405 generates synchronization signals for the DMD driving unit 411 and the actuator driving circuits 404 a to 404 d from the two subframe signals generated by the image signal processing unit 410. The DMD driving unit 411 generates a DMD driving signal so that the two subframe signals generated by the image signal processing unit 410 are output at a speed twice the output frame rate. The actuator drive circuits 404a to 404d drive the actuators 404a to 404d in synchronization with the DMD drive unit 411, and generate actuator drive signals so as to move the projection positions of the pixels.

  A specific operation example of the image output system 4000 will be described with reference to FIGS. Here, in the projector 100, the DMDs 240, 250, and 260 can output an image of horizontal 1920 pixels × vertical 1080 pixels. Further, the projection position is set to be shifted (shifted) by ½ pixel in the horizontal direction and ½ pixel in the vertical direction by driving the parallel flat glass 400 with an actuator. Here, to shift by 1/2 pixel (or half pixel) means to move the pixel to a position half the pitch between pixels.

  FIG. 8 shows an image signal serving as a base for creating a subframe image in the image output system 4000 of the projector 100, which is a so-called 4K2K image of 3840 pixels in the horizontal direction × 2160 pixels in the vertical direction. The number of pixels of the base image signal is four times the number of pixels of the DMDs 240, 250, and 260. The base image signal may be an image signal directly input from an external device, or may be a signal obtained by up-converting a lower resolution input image inside the system.

A subframe image signal creation method in the image signal processing unit 410 will be described. FIG. 9 shows a method of creating two subframe signals (resampled image signals) by resampled from one frame of the base image signal shown in FIG. 8 at different sample positions. In the base image signal of FIG. 8, the pixel column numbers are assigned as 0, 1, 2, 3, 4, 5,... In the horizontal direction, and the pixel row numbers are 0, 1, 2, 3, in the vertical direction. It is marked with.
1) The remainder obtained by dividing the numerical value indicating the number of the column number counted from column number 0 in the horizontal direction by 2 is 0, and the number of the row number counted from row number 0 in the vertical direction A signal obtained by sampling a pixel whose remainder is 0 after dividing a numerical value indicating whether or not by 2 is a first subframe signal.
2) The remainder of dividing the numerical value indicating the number of the column number counted from column number 0 in the horizontal direction by 2 is 1, and the number of the row number counted from row number 0 in the vertical direction A signal obtained by sampling a pixel having a remainder of 1 obtained by dividing the numerical value indicating “2” by 2 is defined as a second subframe signal.

DMDs 240, 250, and 260 output two subframes at twice the output frame rate. Specifically, if the output frame rate is 60 Hz, the subframe is output at 120 Hz, and the actuator is driven at 60 Hz. FIG. 10 schematically shows the displacement (VCM displacement amount) instructed to the actuator and the movement of the sub-frame image at this time. In this case, as shown in FIG. 10, a displacement A is instructed to the actuator A, and a displacement C obtained by inverting the displacement A is instructed to the actuator C. The actuator B and the actuator D do not change the displacement. As a result, the parallel flat glass 400 is swung with the BD axis as the rotation axis, so that the optical path of the input image light is changed, and the first sub-frame image (first SF) and the first sub-frame image shifted by half a pixel from each other. Two sub-frame images (second SF) are projected.
[4x dense image output operation]
The image signal processing unit 410 generates four subframe image signals corresponding to the movement of the projection position by the parallel flat glass 400 and the actuators 401a to 401d for each frame of the input image signal.

  The four subframe image signals generated by the image signal processing unit 410 are sent from the microcomputer 405 to the DMD driving unit 411, and a DMD driving signal is generated so as to be output at a speed four times the output frame rate. The microcomputer 405 generates an actuator drive signal so as to drive the parallel flat glass 400 in synchronization with the DMD drive unit 411 and move the projection position of the pixel, and outputs the actuator drive signal to the drive circuits 404a to 404d.

  The operation of the image output system when the projection position can be moved in two directions will be described with reference to FIGS. The corresponding resolution of the display element and the resolution of the base image signal are the same as those described in the case of the double density image output operation.

  A subframe signal generation method in the image signal processing unit 410 will be described. FIG. 11 shows a method of generating four subframe signals (resampled image signals) by resampled from one frame of the base image signal shown in FIG. 8 at different sample positions.

In the base image signal shown in FIG.
1) A remainder obtained by dividing a numerical value indicating the number counted from 0 in the horizontal direction by 2 is 0, and a remainder obtained by dividing the numerical value indicating the number counted from 0 in the vertical direction by 2 A signal obtained by sampling a pixel that is 0 is defined as a first subframe.
2) The remainder obtained by dividing the numerical value indicating the number starting from 0 in the horizontal direction by 2 is 1, and the numerical value indicating the number counting from 0 in the vertical direction is divided by 2. A signal obtained by sampling a pixel that is 0 is defined as a second subframe.
3) The remainder obtained by dividing the numerical value indicating the number counted from 0 in the horizontal direction by 2 is 1, and the remainder obtained by dividing the numerical value indicating the number counted from 0 in the vertical direction by 2 A signal obtained by sampling a pixel that is 1 is defined as a third subframe.
4) The remainder obtained by dividing the numerical value indicating the number counted from 0 in the horizontal direction by 2 is 0, and the remainder obtained by dividing the numerical value indicating the number counted from 0 in the vertical direction by 2 A signal obtained by sampling a pixel that is 1 is defined as a fourth subframe.

  DMDs 240, 250, and 260 output four subframes at a rate four times the output frame rate. Specifically, if the output frame rate is 60 Hz, the subframe is output at 240 Hz, and the actuator is driven at 60 Hz.

FIG. 12 schematically shows the displacement (VCM displacement) instructed to the actuator and the movement of the sub-frame image at this time. In this case, a displacement A is instructed to the actuator A, and a displacement C obtained by inverting the displacement A is instructed to the actuator C. A displacement B is instructed to the actuator B, and a displacement D obtained by inverting the displacement B is instructed to the actuator D. The displacement waveforms instructed to the actuator B and the actuator D are shifted in phase by 90 ° with respect to the displacement waveforms instructed to the actuator A and the actuator C. As a result, the parallel flat glass 400 is swung with the BD axis and the A-C axis as the rotation axes, so that the optical path of the input image light is displaced in the horizontal and vertical directions, and is shifted by one half pixel from each other. A sub-frame image (first SF), a second sub-frame image (second SF), a third sub-frame image (third SF), and a fourth sub-frame image (fourth SF) are projected.
[Switch processing by input signal]
In the present embodiment, appropriate image signal processing is selected depending on the type of input image signal.

FIG. 13 collectively describes the drive circuit, actuator, position sensor, position detection circuit, and shift amount operation unit illustrated in FIG. 2 as one block as the shift control unit 413.
The circuit configuration of FIG. 13 is provided in the projector 100 except for the PC 417.

  In the present embodiment, an image signal supplied to the projector is generated by a personal computer (PC) 417, and an image signal output from the PC 417 is input to the image signal input unit 414. At the same time, the control signal output from the PC 417 is input to the control signal input unit 415.

  The signal determination unit 416 determines the type of image from the image signal input to the image signal input unit 414 and the control signal input to the control signal input unit 415. The discrimination of the type of image referred to here is to discriminate whether or not the image requires resampling, whether or not the image has undergone pixel shift processing, and the like.

  The image signal processing unit 410 performs a resampling process on the image signal in the resampling unit 4100 based on the result determined in the signal determination unit 416. The synchronization signal generation unit includes a microcomputer 405, and generates a synchronization signal for operating the image output by the DMD and the pixel shift in synchronization. The DMD drive unit 411 drives the DMD so that the image output from the image signal processing unit 410 is displayed according to the synchronization signal output from the synchronization signal generation unit. When the pixel shift is performed, the shift control unit 413 drives the optical element driving device so that the display position of the image projected on the projection plane is shifted according to the synchronization signal output from the microcomputer 405.

  FIG. 14 shows an example of a specific image signal generated by the PC 417.

  The resolution of the DMD of the projector 100 to which the image signal is input from the PC 417 is 1920 horizontal pixels × 1080 vertical pixels (2K), and the pixel shift causes the resolution to be 3840 horizontal pixels × 2160 vertical pixels (4K). In FIG. 14, the image signal output from the PC 417 is transmitted through one image signal cable and input to the projector 100. Further, the control signal cable inputs a timing designation signal from the PC 417 to the projector 100.

  In the case (A) of FIG. 14, the PC 417 generates an image signal with a resolution of 4K and a frame rate of 60 Hz, and inputs this image signal to the image signal input unit 414 of the projector.

  The image signal input unit 414 acquires information about the resolution and frequency (frame rate) of the input image and supplies the information to the signal determination unit 416. In addition, a constant voltage signal is input from the PC 417 to the control signal input unit 415 as a control signal.

  The image signal input unit 414 determines the frame rate of the input image signal from the number of vertical synchronization signals per second of the input image signal that has been input, and at the same time the horizontal synchronization signal, vertical synchronization signal, and pixel clock of the input image signal. Based on the above, the resolution of the input image signal is determined.

  In this case (A), since the resolution is 4K and the frequency of the image signal is 60 Hz, the signal determination unit 416 determines that the image is a high-resolution image that requires resampling and pixel shift. At this time, the control signal input from the PC 417 to the control signal input unit 415 is a low level signal. However, when it is determined that the resolution is 4K and the frame rate is 60 Hz, the input image signal is displayed in a pixel shift manner. Since it is known that the signal is a power signal, it is not determined that the signal is a pixel shift signal depending on the content of the control signal.

  The image signal input from the image signal input unit 414 to the image signal processing unit 410 is resampled (resampled) by the resampling unit 4100 of the image signal processing unit 410. As a result, the image signal processing unit 410 generates four 2K resampled image subframe images from the 4K image. This resampling process is the same as that described in the item “4 × dense image output operation”.

  The microcomputer 405 serving as the synchronization signal generation unit generates a synchronization signal based on the subframe image generation timing in the image signal processing unit 410 so that the display timing of the four subframe images and the pixel shift timing match. . Specifically, a synchronization signal indicating the display timing of the first subframe is generated. The DMD driving unit displays the first subframe in accordance with the synchronization signal, and sequentially displays the second, third, and fourth subframes. The display frequency is 240 Hz, which is four times 60 Hz.

  The shift control unit 413 controls the optical element driving device so that the first subframe is displayed on the upper left in accordance with the synchronization signal. Further, the optical element driving device is controlled so that the second, third, and fourth subframes are displayed on the upper right, lower right, and lower left, respectively. In the figure, only the pixel positions of the first subframe and the third subframe are shown as representatives. In the case (A), since the control signal is not particularly required, the same processing can be performed even when the control signal cable is not connected.

  As described above, in the case (A), the resolution of the image displayed on the projection plane is equivalent to the 4K image due to the pixel shift.

  In the case (B), the PC 417 generates an image signal with a resolution of 2K and a frame rate of 240 Hz and inputs the image signal to the image signal input unit 414.

  The image signal input unit 414 acquires information about the resolution and frequency (frame rate) of the input image and supplies the information to the signal determination unit 416. In addition, a signal S indicating the timing of the first subframe is supplied from the PC 417 to the control signal input unit 415 as a control signal. The signal S is supplied after the start of the fourth subframe and before the start of the first subframe, indicating that the next frame is the first subframe. The control signal input to the control signal input unit 415 is input to the signal determination unit 416 and the image signal processing unit 410.

  The signal determination unit 416 determines that the resolution of the input image signal input to the image signal input unit 414 is 2K and the frequency (frame rate) of the image signal is 240 Hz, and determines that the image does not require resampling. To do. Therefore, in this case, the resampling unit 4100 of the image signal processing unit 410 does not perform resampling. Further, since the control signal is a signal (synchronization signal) indicating timing for distinguishing subframes, it is determined that the image has been subjected to pixel shift processing that requires pixel shift.

  The microcomputer 405 serving as a synchronization signal generation unit generates a synchronization signal so that the display of the four subframe images and the pixel shift timing are matched. Specifically, based on the signal S indicating the timing of the first subframe input to the image signal processing unit 410, a synchronization signal indicating the display timing of the first subframe is generated. The DMD driving unit displays the first subframe in accordance with the synchronization signal, and sequentially displays the second, third, and fourth subframes. The display frequency at this time is 240 Hz.

  The shift control unit controls the optical element driving device so that the first subframe is displayed on the upper left in accordance with the synchronization signal. Further, the optical element driving device is controlled so that the second, third, and fourth subframes are displayed on the upper right, lower right, and lower left, respectively. In the figure, only the pixel positions of the first subframe and the third subframe are shown as representatives.

  Thus, in the case (B), since the pixel shift is performed, the resolution of the image displayed on the projection plane corresponds to a 4K image.

  In case (C), the PC 417 generates an image signal with a resolution of 2K and a frame rate of 240 Hz, and inputs the image signal to the image signal input unit 414.

  The image signal input unit 414 acquires information about the resolution and frequency (frame rate) of the input image and supplies the information to the signal determination unit 416. In addition, a constant voltage signal is input from the PC 417 to the control signal input unit 415 as a control signal.

  The signal determination unit 416 determines that the resolution of the input image signal input to the image signal input unit 414 is 2K and the frequency (frame rate) of the image signal is 240 Hz, and determines that the image does not require resampling. To do. Further, since the control signal is a signal having a constant voltage, it is determined that the image does not require pixel shift. The image processing unit does not perform resampling. The microcomputer 405 serving as a synchronization signal generation unit generates a synchronization signal that designates the display timing of four subframe images. The DMD driving unit displays the first subframe in accordance with the synchronization signal, and sequentially displays the second, third, and fourth subframes.

  Thus, in case (C), since pixel shift is not performed, the resolution of the image displayed on the projection plane corresponds to a 2K image.

In the case (C), the same processing may be performed even when the cable of the control signal is not connected.
[Modification of Embodiment]
FIG. 15 shows a modification of the embodiment.

  The projector 1000 of this modification is different from the projector 100 in the above embodiment in that the resolution of the DMD is different. That is, the DMD resolution of the projector 1000 of this modification is 2560 pixels wide × 1440 pixels high (2.5K), and the resolution is 5120 pixels wide × 2880 pixels high (5K) due to pixel shift.

  In FIG. 15, the image output from the PC 417 is transmitted through four image signal cables and input to the projector 1000. Further, the control signal cable transmits a signal indicating whether the image is a 60 Hz image or a 240 Hz image and a signal indicating the necessity / unnecessity of the pixel shift, and inputs them to the projector 1000.

  In the case (A) of FIG. 15, the PC 417 generates an image signal with a resolution of 5K and a frame rate of 60 Hz, and divides the image signal into four 2.5K and 60 Hz partial images and inputs them to the image signal input unit 414 of the projector 1000. doing.

  The image signal input unit 414 acquires information about the resolution of the input image and supplies it to the signal determination unit 416. In addition, a signal (Low signal) indicating that the image is a 60 Hz image (2.5K 240 Hz mode OFF) is input from the PC 417 to the control signal input unit 415 as a control signal. At this time, the control signal input from the PC 417 to the control signal input unit 415 is a low level signal. However, when it is determined that the resolution is 5K and the frame rate is 60 Hz, the input image signal is displayed in a pixel shift manner. Since it is known that the signal is a power signal, it is not determined that the signal is a pixel shift signal depending on the content of the control signal.

  The signal determination unit 416 determines from the resolution information and the control signal information that the image is a high-resolution image that requires resampling and pixel shift. The image signal processing unit generates four 2.5K sub-frame images (pixel shift images) by resampling from the four 2.5K partial images. That is, the projector generates a 5K 1-frame base image (a 5K 60 Hz image generated by the PC) from the four 2.5K partial images, and the image signal processing unit 410 as in the previous embodiment. The resampling unit 4100 resamples (resamples) four 2.5K sub-frame images.

  The microcomputer 405 serving as the synchronization signal generation unit generates a synchronization signal based on the subframe image generation timing in the image signal processing unit 410 so that the display timing of the four subframe images and the pixel shift timing match. . Specifically, a synchronization signal indicating the display timing of the first subframe is generated. The DMD driving unit displays the first subframe in accordance with the synchronization signal, and sequentially displays the second, third, and fourth subframes. The display frequency is 240 Hz, which is four times 60 Hz.

  The shift control unit 413 controls the optical element driving device so that the first subframe is displayed on the upper left in accordance with the synchronization signal. Further, the optical element driving device is controlled so that the second, third, and fourth subframes are displayed on the upper right, lower right, and lower left, respectively. In the figure, only the pixel positions of the first subframe and the third subframe are shown as representatives.

  Thus, in the case (A), the resolution of the image displayed on the projection plane is equivalent to a 5K image due to pixel shift.

  In the case (B), the PC 417 generates an image signal having a resolution of 2.5K and a frame rate of 240 Hz, and then generates four image signals having a frame rate of 60 Hz from the video signal. Video 1, video 2, video 3, and video 4) are input to the image signal input unit 414. The four image signals are first, second, third, and fourth subframe images, respectively.

  The image signal input unit 414 acquires information about the resolution of the input image and supplies it to the signal determination unit 416. In addition, a signal (High signal) indicating that the image is a 240 Hz image (2.5K 240 Hz mode ON) and a signal indicating that a pixel shift is necessary (High signal) are input from the PC 417 to the control signal input unit 415 as control signals. Is done.

  The signal determination unit 416 determines from the resolution information and the control signal information that the pixel shift image does not require resampling and requires pixel shift. Therefore, resampling is not performed in the image signal processing unit.

  The microcomputer 405 serving as a synchronization signal generation unit generates a synchronization signal so that the display of the four subframe images and the timing of pixel shift are matched. Specifically, a synchronization signal indicating the display timing of the first subframe is generated. The DMD driving unit displays the first subframe in accordance with the synchronization signal, and sequentially displays the second, third, and fourth subframes. The display frequency is 240 Hz.

  The shift control unit controls the optical element driving device so that the first subframe is displayed on the upper left in accordance with the synchronization signal. Further, the optical element driving device is controlled so that the second, third, and fourth subframes are displayed on the upper right, lower right, and lower left, respectively. In the figure, only the pixel positions of the first subframe and the third subframe are shown as representatives.

  Thus, in the case (B), the resolution of the image displayed on the projection plane is equivalent to a 5K image due to the pixel shift.

  In this case, the PC 417 generates an image signal with a resolution of 2.5K and a frame rate of 240 Hz, and then generates four image signals with a frame rate of 60 Hz from the video signal, each of which is composed of four cables ( Video 1, Video 2, Video 3, and Video 4) are input to the image signal input unit 414. The PC 417 generates an image signal having a resolution of 2.5K and a frame rate of 240 Hz. The video signal may be input to the image signal input unit 414 in the order of video 1, video 2, video 3, video 4, video 1, video 2, video 3, video 4 using a cable.

  In the case (C), the PC 417 generates an image signal having a resolution of 2.5K and a frame rate of 240 Hz, and then generates four image signals having a frame rate of 60 Hz from the video signal, and each of them includes four cables ( Video 1, video 2, video 3, and video 4) are input to the image signal input unit 414. The four image signals are first, second, third, and fourth subframe images, respectively.

  The image signal input unit 414 acquires information about the resolution of the input image and supplies it to the signal determination unit 416. In addition, a signal (High signal) indicating that the image is a 240 Hz image (2.5K 240 Hz mode ON) and a signal (Low signal) indicating that pixel shift is unnecessary are input to the control signal input unit 415 as control signals. .

  The signal determination unit 416 determines from the resolution information and control signal information that the image does not require resampling and does not require pixel shift. Therefore, resampling is not performed in the image processing unit.

  The microcomputer 405 serving as a synchronization signal generation unit generates a synchronization signal that designates the display timing of four subframe images. The DMD driving unit displays the first subframe in accordance with the synchronization signal, and sequentially displays the second, third, and fourth subframes.

  Thus, in the case (C), the resolution of the image displayed on the projection surface corresponds to a 2.5K image.

  Next, an example of an image generation method in the PC will be shown. As shown in FIG. 16, the PC 417 includes an image generation unit 417a and an image signal output unit 417b that outputs an image signal generated by the image generation unit 417a.

  Image generation processing by computer graphics (CG) will be described with reference to FIGS. As shown in FIG. 17, CG arranges model data in a virtual space. Also, the viewpoint, line-of-sight direction, and angle of view are set, and the projection plane and resolution are specified. From the above information, the position of each pixel on the projection plane is determined. Further, the number of times (frequency) of generating an image per second is designated. Then, as shown in FIG. 18, the intersection of the line connecting the viewpoint and each pixel of the projection plane and the model data is calculated, and the color information of the intersection closest to the viewpoint is used as the pixel information of each pixel.

  In case (A) of FIG. 14, the PC 417 generates an image by CG with a resolution of 4K and a frequency of 60 Hz.

  In the cases (B) and (C) of FIG. 14, the PC 417 generates an image by CG with a resolution of 2K and a frequency of 240 Hz.

  In case (A) of FIG. 15, the PC 417 generates an image by CG with a resolution of 5K and a frequency of 60 Hz.

  In case (B) and case (C) of FIG. 15, the PC 417 generates an image by CG with a resolution of 2.5K and a frequency of 240 Hz.

  Further, in the case (B) of FIG. 14 and the case (B) of FIG. 15, while performing pixel shift processing for periodically switching the pixel position in a range of less than one pixel (for example, 1/2 of the pixel pitch) for each frame. Image generation is performed to obtain a frame image signal. In this case, since the frequency is 240 Hz, frame images with frame numbers 0 to 239 are generated per second. A frame with a remainder of 0 obtained by dividing the frame number by 4 is designated as a first subframe, and similarly, a frame with a remainder of 1, 2, and 3 obtained by dividing the frame number by 4 is designated as a second, third, and fourth subframe, respectively. To do. Then, the pixel positions of the first, second, third, and fourth subframes are changed. The pixel positions of the first frames, the second frames, the third frames, and the fourth frames are the same.

  As shown in FIG. 19, the pixel position of the second frame is shifted to the right with respect to the pixel position of the first frame. Although not shown, the pixel position of the third frame is shifted downward with respect to the pixel position of the second frame. Similarly, the pixel position of the fourth frame is shifted to the left with respect to the pixel position of the third frame. All shift amounts are half the pixel pitch. The pixel position can be shifted by changing the viewing direction and the angle of view.

  In the above configuration, a case where resampling is performed and a case where it is not performed are mixed. These are essentially different systems. For example, as shown in FIG. 20A, the configuration differs depending on whether an image signal having a resolution of 4K and a frequency of 60 Hz is received, and receiving an image signal having a resolution of 2K and a frequency of 240 Hz as shown in FIG. The method of taking can be considered.

  In the present disclosure, by using a single system as shown in FIG. 13, the configuration other than the image processing unit can be shared and the two systems can coexist. And it becomes possible to cope with various inputs without preparing separate systems.

  For example, in a PC, a 4K60 Hz image and a 2K240 Hz image are selectively output. In desktop display, an image of 4K60 Hz is output. On the other hand, when software that uses computer graphics is started, an image of 2K240 Hz can be output. Furthermore, software that does not have a pixel shift function simply outputs a 2K240 Hz image, but software that has a pixel shift function can output an image that is pixel-shifted at 2K240 Hz. In the present disclosure, in any of these cases, the optimum display can be automatically performed.

  As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments that have been changed, replaced, added, omitted, and the like. Moreover, it is also possible to combine each component demonstrated in the said embodiment and it can also be set as a new embodiment.

  The present disclosure is applicable to a projection-type image display device that can shift a pixel display position and display a high-definition projection image.

100, 1000 Projector 130 Light source 240, 250, 260 DMD
400 Parallel flat glass 405 Microcomputer 410 Image signal processing unit 411 DMD driving unit 413 Shift control unit 414 Image signal input unit 415 Control signal input unit 416 Signal discrimination unit 417 PC
417a Image generation unit 417b Image signal output unit 4000 Image output system 4100 Resampling unit

Claims (2)

An image signal input in which one of a first image signal that is a high-resolution image signal and a second image signal that is a lower-resolution image signal that has been subjected to pixel shift processing is input as an input image signal. And
A signal discriminating unit for discriminating whether the input image signal input to the image signal input unit is a first image signal or a second image signal;
Resampled images having the same resolution as the second image signal and displayed at the same frame rate by resampling the first image signal of one frame input to the image signal input unit at different sample positions. A resampling unit for generating a signal;
Based on the determination result of the signal determination unit, an image signal processing unit that performs any one of a process of generating a resampled image signal in the resampling unit and a process of outputting a second image signal;
A light modulation element that generates image light obtained by modulating light from a light source based on a resampled image signal or a second image signal obtained from the image signal processing unit;
An image shift unit that shifts the image light emitted from the light modulation element in units of frames;
A projection-type image display device comprising: An image signal generation device for generating an input image signal to be input to the projection type image display device according to claim 1,
An image generation unit that generates a frame image signal by performing image generation while performing pixel shift processing that periodically switches a pixel position to be generated for each frame within a range of less than one pixel;
An image signal output unit that outputs an image signal generated by the image generation unit as the second image signal;
An image signal generation device comprising: