JP7809936B2 - Projection device, projection method, and program - Google Patents

Description

The present invention relates to a projection device, a projection method, and a program.

Commercially available projectors place a rapidly rotating color wheel (or phosphor wheel) between the projector's light source unit and a micromirror element called a DMD (Digital Micromirror Device). The output of each light source is switched on and off at the timing of the segment switch within the color wheel (the middle timing of the spoke period). This allows the light source unit to emit primary color light consisting of, for example, red light (R), green light (G), and blue light (B) toward the DMD in a time-division manner. The projection processing unit that controls the DMD outputs light source pulses to instruct the output of each light source to be switched on and off at the timing of the segment switch within the color wheel (the middle timing of the spoke period).

This light source pulse is output in the middle of the spoke period, not in time with the start of the spoke period. This creates a period in which the two colors of light mix. If this mixed light is discarded unused, it could cause degradation of image quality, resulting in a loss of light source energy (loss of brightness).

JP 2016-81819 A

The present invention provides a projection device, projection method, and program that effectively controls the timing of light output from a light source unit.

A projection device according to one aspect of the present invention comprises a light source driving unit including a plurality of D flip-flops, wherein a first of the plurality of D flip-flops receives a first light emission signal at an input terminal for emitting light of a first color, and when receives an enable signal at a clock terminal for switching from emitting the first color to emitting a second color during a spoke period, outputs a second light emission signal from an output terminal for emitting the second color, and controls the light source unit to emit light of the second color based on the output second light emission signal .

The present invention provides a projection device, projection method, and program that effectively controls the timing of light output from a light source unit.

FIG. 1 is a block diagram of a projection device according to an embodiment of the present invention. FIG. 2 is a block diagram of the light source unit shown in FIG. FIG. 3 is a plan view of the phosphor wheel shown in FIG. FIG. 4 is a block diagram of the projection processing unit and the light source driving unit shown in FIG. FIG. 5 is a timing chart illustrating the light source switching operation of the projection device according to the comparative example. FIG. 6 is a timing chart illustrating the light source switching operation of the projection device according to the embodiment.

Embodiments will be described below with reference to the drawings. However, the drawings are schematic or conceptual, and the dimensions and proportions of each drawing are not necessarily the same as those in reality. The several embodiments shown below are examples of devices and methods that embody the technical concepts of the present invention, and the shape, structure, arrangement, etc. of the components do not define the technical concepts of the present invention. In the following description, elements with the same function and configuration will be given the same reference numerals, and duplicate explanations will be omitted.

[1] Configuration of Projection Device 10 Fig. 1 is a block diagram of a projection device 10 according to an embodiment of the present invention. The projection device 10 is configured as a projector that complies with the DLP (registered trademark) (Digital Light Processing) system, for example.

The projection device 10 includes an input/output connector 11, an input/output interface (I/F) 12, a bus 13, an image conversion unit 14, a VRAM (Video RAM) 15, a projection processing unit 16, a light source driving unit 17, a light source unit 18, a micromirror element (also called a display element) 19, a mirror 20, a projection lens unit 21, an audio processing unit 22, a speaker 23, a CPU (Central Processing Unit) 24, a memory unit 25, an operation unit 26, and a power supply circuit 27.

The input/output interface 12, image conversion unit 14, VRAM 15, projection processing unit 16, audio processing unit 22, and CPU 24 are connected via bus 13 so that they can send and receive data to and from each other.

The input/output connector 11 is a terminal through which the projection device 10 inputs image data to be projected from an external device. The input/output connector 11 is implemented, for example, by an HDMI (registered trademark) (High-Definition Multimedia Interface) terminal, a pin jack (RCA) type video input terminal, a D-sub15 type RGB input terminal, or a USB (Universal Serial Bus) connector. Furthermore, removable media such as a magnetic disk, optical disk, magneto-optical disk, or semiconductor memory that stores programs, image data, etc., can be attached to the input/output connector 11 as appropriate.

Programs read from removable media via the input/output connector 11 are stored in the memory unit 25 as needed. The removable media can also store various data stored in the memory unit 25 in the same way as the memory unit 25.

Image data conforming to various standards input to the input/output connector 11 is sent to the image conversion unit 14 via the input/output interface 12 and bus 13.

The image conversion unit 14 converts the image data sent from the input/output connector 11 into an image signal in a predetermined format suitable for projection. The image conversion unit 14 also sends the converted image signal to the projection processing unit 16.

VRAM 15 is a buffer memory for image processing. VRAM 15 is used as a buffer when transmitting image signals from the image conversion unit 14 to the projection processing unit 16.

The projection processing unit 16 drives the micromirror element 19 using time-division driving that multiplies the frame rate, number of color component divisions, and number of display gradations that conform to a predetermined format in response to the image signal transmitted from the image conversion unit 14.

The micromirror element 19 is a spatial light modulation element that is driven under the control of the projection processing unit 16. The micromirror element 19 has multiple micromirrors that correspond to multiple pixels arranged in an array (for example, 1024 horizontal pixels by 768 vertical pixels corresponding to XGA). The micromirror element 19 quickly switches the tilt angle of each of the multiple micromirrors on and off. When the micromirrors are on, the micromirror element 19 forms an optical image corresponding to the image signal using reflected light emitted to the projection lens unit 21.

The light source unit 18 cyclically emits multiple colored light (including the primary color light of R (red), G (green), and B (blue)) in a time-division manner. The multiple colored light from the light source unit 18 is totally reflected by the mirror 20 and irradiated onto the micromirror element 19.

The projection processing unit 16 adjusts the time that the micromirror element 19 is on for a predetermined period of time determined for each of the multiple colors of light incident on the micromirror element 19, thereby adjusting the color to correspond to the color components of the input image signal. An optical image is then formed from the light reflected by the micromirror element 19, and the formed optical image is projected and displayed via the projection lens unit 21 onto a screen (not shown) that is the projection target.

The light source driver 17 controls the emission timing and intensity of the semiconductor lasers and LEDs included in the light source unit 18, as well as the rotation of the phosphor wheel driven by the motor, based on the timing signal in the image signal sent from the projection processor 16, the index signal input from the index sensor, and brightness information input from the optical sensor (not shown). Control by the light source driver 17 is performed under the overall control of the CPU 24.

The audio processing unit 22 includes a sound source circuit such as a PCM (Pulse Code Modulation) sound source. The audio processing unit 22 converts the audio data sent from the CPU 24 during projection operation into analog data and drives the speaker 23 to emit amplified sound.

The storage unit 25 includes ROM (Read Only Memory) as non-volatile memory and RAM (Random Access Memory) as volatile memory. The ROM stores various programs and data. The ROM also stores the drive current values of the LEDs and semiconductor lasers when emitting R, G, and B as rated current values when the white balance is achieved at the time of factory shipment. The RAM is used as work memory for the CPU 24.

The CPU 24 comprehensively controls the operation of each of the above circuits. The CPU 24 is also called a control unit. The CPU 24 executes various processes based on programs stored in ROM or programs loaded into RAM from removable media. The RAM stores data necessary for the CPU 24 to execute various processes as appropriate.

The CPU 24 performs various adjustment operations for the projection operation in response to operation signals, which are signals based on key operations received by the operation unit 26 from the user.

The operation unit 26 includes a key operation unit provided on the main body of the projection device 10 and a laser light receiving unit that receives infrared light between the key operation unit and a remote controller (not shown) dedicated to the projection device 10. The operation unit 26 transmits operation signals to the CPU 24 based on key operations entered by the user on the key operation unit of the main body or the remote controller.

The operation unit 26, including the key operation unit and the remote controller, includes, for example, a focus adjustment key, a zoom adjustment key, an input switching key, a menu key, a cursor key, a set key, and a cancel key.

The power supply circuit 27 uses an externally supplied power source to generate various voltages required for the operation of the multiple circuits included in the projection device 10. The power supply circuit 27 supplies the generated voltages to the corresponding circuits. The power supply circuit 27 is equipped with a battery. When the supply of external power is stopped, the power supply circuit 27 uses the battery to generate various voltages and supplies them to the corresponding circuits.

[1-1] Configuration of light source unit 18 Fig. 2 is a block diagram of the light source unit 18 shown in Fig. 1. The light source unit 18 includes a semiconductor laser 31 for emitting B light, an LED 32 for emitting R light, a mirror 33, a dichroic mirror 34, a phosphor wheel 35, an index sensor 36, a motor (M) 37, a mirror 38, a mirror 39, a dichroic mirror 40, an integrator 41, and a mirror 42. The semiconductor laser 31 is also called a laser diode (LD).

The light source unit 18 is equipped with two types of light-emitting elements (light sources). Specifically, the light source unit 18 is equipped with a semiconductor laser 31 that emits blue laser light (also called blue light) and an LED 32 that emits red light. Note that in Figure 2, the letters R, G, and B and the arrows indicate the color of light (either R, G, or B) and the direction of travel of the light.

The blue laser light emitted by the semiconductor laser 31 is totally reflected by the mirror 33, then passes through the dichroic mirror 34 and is irradiated onto a portion of the circumference of the phosphor wheel 35.

The phosphor wheel 35 is made of an annular member and is connected to the rotation shaft of the motor 37. The phosphor wheel 35 is rotated at a constant speed by the motor 37. The circumference of the phosphor wheel 35, onto which the laser light is irradiated, is provided with a transmissive area that transmits the light and a reflective area that reflects the light. The transmissive area of the phosphor wheel 35 functions as a diffuser that diffuses the light. The reflective area of the phosphor wheel 35 is coated with fluorescent paint, and this reflective area functions as a green fluorescent reflector. The specific configuration of the phosphor wheel 35 will be described later.

When the transmission area of phosphor wheel 35 is located at the laser light irradiation position, the laser light is diffused in this transmission area and passes through phosphor wheel 35, after which it is totally reflected by mirrors 38 and 39. This laser light then passes through dichroic mirror 40, is converted into a light beam with a substantially uniform brightness distribution by integrator 41, is totally reflected by mirror 42, and is emitted to mirror 20.

When the reflective area of phosphor wheel 35 is located at the position where the laser light is irradiated, the laser light (blue light) is converted to green light, and the converted green light is reflected by phosphor wheel 35 and then reflected by dichroic mirror 34. This green light is then reflected by dichroic mirror 40, converted into a light beam with a substantially uniform brightness distribution by integrator 41, and then totally reflected by mirror 42 and emitted to mirror 20.

The red light emitted by the LED 32 passes through the dichroic mirror 34, is reflected by the dichroic mirror 40, is converted into a light beam with a substantially uniform brightness distribution by the integrator 41, is then totally reflected by the mirror 42, and is emitted to the mirror 20.

As described above, dichroic mirror 34 has the spectral characteristics of transmitting blue and red light while reflecting green light. Dichroic mirror 40 also has the spectral characteristics of transmitting blue light while reflecting red and green light.

A rotational position detection mark is provided on the rotation shaft of the motor 37. An index sensor 36 is positioned at a position where the rotational position detection mark can be detected. The index sensor 36 is, for example, a reflective photointerrupter (also called a reflective photosensor). The index sensor 36 generates an index signal that indicates the timing of detection of the rotational position detection mark. The index sensor 36 then outputs the generated index signal to the light source driver 17.

In addition, an optical sensor (not shown) is disposed facing the light output side of the integrator 41. This optical sensor detects only the brightness, regardless of the color of the light. Information on the brightness detected by the optical sensor is output to the light source driver 17.

The light source driver 17 includes a counter 28. The counter 28 counts pulses of the lamp enable signal LAMP_ENBL generated by the projection processor 16. The light source driver 17 executes light emission processing based on the count value of the counter 28. Details of the lamp enable signal LAMP_ENBL will be described later.

[1-2] Configuration of the Phosphor Wheel 35 FIG. 3 is a plan view of the phosphor wheel 35 shown in FIG.

The phosphor wheel 35 is configured in a circular ring shape. A hole-shaped bearing 51 is provided at the center of the phosphor wheel 35. The bearing 51 is attached to the rotation shaft of the motor 37. The phosphor wheel 35 can be rotated by being driven by the motor 37.

The base material 50 of the phosphor wheel 35 is made of a metal such as copper or aluminum. The surface of this base material 50 facing the light source is mirror-finished by silver vapor deposition or the like. The phosphor wheel 35 has transmissive regions 52 and reflective regions 53 arranged side by side in the circumferential direction.

The reflective region 53 of the phosphor wheel 35 is provided on the mirror-finished surface of the substrate 50 and is formed by forming a green phosphor layer on the substrate 50. The reflective region 53 receives the blue laser light (blue wavelength band light) emitted by the semiconductor laser 31 as excitation light, and emits green light (green wavelength band light). This green light is reflected by the phosphor wheel 35.

The transmissive region 52 of the phosphor wheel 35 is formed by fitting a translucent member into a cutout formed in the base material 50 of the phosphor wheel 35. The transparent member is made of a transparent material such as glass or resin. The transparent member may also have a diffusion layer on the surface on the side irradiated with blue light or on the opposite side. Blue light incident on the transmissive region 52 is transmitted or diffused through the transmissive region 52.

One frame is the time it takes for the phosphor wheel 35 to make one revolution. In one frame, the multiple colors of light that the light source unit 18 can emit circulate in a time-division manner. One revolution of the phosphor wheel 35 is 360 degrees, and the timing of emitting light of each color can be expressed as an angle.

[1-3] Configuration of the Projection Processing Unit 16 and the Light Source Driving Unit 17 FIG. 4 is a block diagram of the projection processing unit 16 and the light source driving unit 17 shown in FIG.

The projection processing unit 16 outputs a lamp enable signal LAMP_ENBL. The lamp enable signal LAMP_ENBL is set to turn ON at the start of a spoke period and OFF at the end of the spoke period, and is output (also called a LAMP_ENBL pulse). In other words, the output state of the pulse signal (= lamp enable signal LAMP_ENBL) changes for each spoke period to switch the light color.

The projection processing unit 16 also outputs a red light emission signal RED_LED1, a green light emission signal GRN_LED1, and a blue light emission signal BLU_LED1. The red light emission signal RED_LED1 is a signal that instructs the emission of red light. The green light emission signal GRN_LED1 is a signal that instructs the emission of green light. The blue light emission signal BLU_LED1 is a signal that instructs the emission of blue light. The lamp enable signal LAMP_ENBL, the red light emission signal RED_LED1, the green light emission signal GRN_LED1, and the blue light emission signal BLU_LED1 are sent to the light source driving unit 17.

The light source driver 17 includes a signal conversion circuit 60. The signal conversion circuit 60 includes three D flip-flops 61 to 63. The D flip-flops transfer data on the rising edge of the clock and hold the data during other periods.

The input terminal D of this rising-edge type D flip-flop 61 receives the red light-emitting signal RED_LED1. The clock terminal of the D flip-flop 61 receives the lamp enable signal LAMP_ENBL. In response to detecting the rising edge "↑" of the lamp enable signal LAMP_ENBL and the high level "1" of the red light-emitting signal RED_LED1, the D flip-flop 61 outputs the high level "1" of the green light-emitting signal GRN_LED2 from the output terminal Q. In addition, in response to detecting the rising edge "↑" of the lamp enable signal LAMP_ENBL and the low level "0" of the red light-emitting signal RED_LED1, the D flip-flop 61 outputs the low level "0" of the green light-emitting signal GRN_LED2 from the output terminal Q. As a result, the light source driver 17 controls the emission of green light using the red light-emitting signal output from the projection processor 16.

The input terminal D of the D flip-flop 62 receives the green light-emitting signal GRN_LED1. The clock terminal of the D flip-flop 62 receives the lamp enable signal LAMP_ENBL. In response to detecting a rising edge "↑" in the lamp enable signal LAMP_ENBL and a high level "1" in the green light-emitting signal GRN_LED1, the D flip-flop 62 outputs a high level "1" in the blue light-emitting signal BLU_LED2 from the output terminal Q. In response to detecting a rising edge "↑" in the lamp enable signal LAMP_ENBL and a low level "0" in the green light-emitting signal GRN_LED1, the D flip-flop 62 outputs a low level "0" in the blue light-emitting signal BLU_LED2 from the output terminal Q. As a result, the light source driver 17 controls the emission of blue light using the green light-emitting signal output from the projection processor 16.

The input terminal D of the D flip-flop 63 receives the blue light-emitting signal BLU_LED1. The clock terminal of the D flip-flop 63 receives the lamp enable signal LAMP_ENBL. In response to detecting a rising edge "↑" in the lamp enable signal LAMP_ENBL and a high level "1" in the blue light-emitting signal BLU_LED1, the D flip-flop 63 outputs a high level "1" red light-emitting signal RED_LED2 from the output terminal Q. In addition, in response to detecting a rising edge "↑" in the lamp enable signal LAMP_ENBL and a low level "0" in the blue light-emitting signal BLU_LED1, the D flip-flop 63 outputs a low level "0" red light-emitting signal RED_LED2 from the output terminal Q. As a result, the light source driver 17 controls the emission of red light using the blue light-emitting signal output from the projection processor 16.

The light source driving unit 17 operates to generate an emission signal for a second color different from the first color using an emission signal for a first color. That is, the light source driving unit 17 generates a signal for green light using the signal for red light generated by the projection processing unit 16. The light source driving unit 17 generates a signal for blue light using the signal for green light generated by the projection processing unit 16. The light source driving unit 17 generates a signal for red light using the signal for blue light generated by the projection processing unit 16. The light source driving unit 17 then controls the operation of the light source unit 14 using the green emission signal GRN_LED2, the blue emission signal BLU_LED2, and the red emission signal RED_LED2.

[2] Operation The operation of the projection device 10 configured as described above will be described. In this embodiment, the projection device 1 performs projection processing using three segments. A segment refers to the type of color of light that can be emitted by the light source unit 18. The three segments are, for example, red (R), green (G), and blue (B).

(Operation of Comparative Example)
First, a light source switching operation according to a comparative example will be described. Fig. 5 is a timing diagram illustrating the light source switching operation of a projection device according to a comparative example. The combined light in Fig. 5 is light emitted from the light source unit. In the comparative example, the projection processing unit operates to emit red light in response to a red light emission signal RED_LED1, green light in response to a green light emission signal GRN_LED1, and blue light in response to a blue light emission signal BLU_LED1.

As an example, the projection device emits light in the order of red (R), green (G), and blue (B) in one frame.

The projection processing unit generates three LAMP_ENBL pulses per frame. The three LAMP_ENBL pulses specify the timing for switching green light, blue light, and red light. The number of LAMP_ENBL pulses is counted by a counter included in the light source driving unit. The light source driving unit determines the type of color to be emitted based on the count value of the counter. The width of the LAMP_ENBL pulse defines the spoke period SP. During the spoke period, the light source unit switches the color of light. In Figure 5, tx, which corresponds to the start timing of the spoke period, indicates the end timing of the spoke period.

At time t0, i.e., the beginning of one frame, the counter's count value is zero. The projection processing unit sets the red light-emitting signal RED_LED1 to high level "1." In this specification, a high level "1" signal indicates activation, and a low level "0" signal indicates deactivation. In response to the rising edge "↑" of the red light-emitting signal RED_LED1, the light source driving unit causes the light source unit to emit red light.

At time t1, the projection processing unit generates the first LAMP_ENBL pulse. The counter value becomes 1.

At time t2, the projection processing unit sets the red light-emitting signal RED_LED1 to low level "0" and the green light-emitting signal GRN_LED1 to high level "1." The rising edge "↑" of the green light-emitting signal GRN_LED1 is set approximately in the center of the spoke period SP. In response to the rising edge "↑" of the green light-emitting signal GRN_LED1, the light source driving unit causes the light source unit to emit green light.

At time t3, the projection processing unit generates a second LAMP_ENBL pulse. The counter value becomes 2.

At time t4, the projection processing unit sets the green light-emitting signal GRN_LED1 to low level "0" and the blue light-emitting signal BLU_LED1 to high level "1." The rising edge "↑" of the blue light-emitting signal BLU_LED1 is set approximately in the center of the spoke period SP. In response to the rising edge "↑" of the blue light-emitting signal BLU_LED1, the light source driving unit causes the light source unit to emit blue light.

At time t5, the projection processing unit generates a third LAMP_ENBL pulse. The counter value becomes 3.

At time t6, the projection processing unit sets the blue light-emitting signal BLU_LED1 to low level "0" and the red light-emitting signal RED_LED1 to high level "1." The rising edge "↑" of the red light-emitting signal RED_LED1 is set approximately in the center of the spoke period SP. The width of the third LAMP_ENBL pulse is set narrower than the width of the second LAMP_ENBL pulse, for example, but the spoke period SP corresponding to the third LAMP_ENBL pulse is set the same as the spoke period SP corresponding to the second LAMP_ENBL pulse. In response to the rising edge "↑" of the red light-emitting signal RED_LED1, the light source driving unit causes the light source unit to emit red light. Time t6 marks the end of one frame. Note that setting the width of the third LAMP_ENBL pulse narrower than the widths of the first and second LAMP_ENBL pulses makes it easier to check the frame period.

After three LAMP_ENBL pulses are generated, the index sensor activates the index signal. When the index signal is activated, the light source driver clears the counter to zero. The R, G, and B light emission processes are then repeated.

In the comparative example, the color switching timing is set to the center of the spoke period SP.

(Operation of the embodiment)
Next, a light source switching operation according to the embodiment of the present invention will be described below: Fig. 6 is a timing chart illustrating the light source switching operation of the projection device 10 according to the embodiment.

As an example, the projection device 10 emits light in the order of red (R), green (G), and blue (B) in one frame. The angles of R, Y, G, and B are examples and can be set appropriately according to specifications.

In Figure 6, the waveforms of the LAMP_ENBL pulse, red light emission signal RED_LED1, green light emission signal GRN_LED1, and blue light emission signal BLU_LED1 are the same as in the comparative example, and the projection processing unit 16 performs the same operation as in the comparative example. That is, the red light emission signal RED_LED1, green light emission signal GRN_LED1, and blue light emission signal BLU_LED1 switch on/off in the center of the spoke period SP.

At time t0, i.e., the beginning of one frame, the count value of the counter 28 is zero. The projection processing unit 16 sets the red light emission signal RED_LED1 to high level "1." The light source driving unit 17 causes the light source unit 18 to emit red light, continuing the operation of the previous frame.

At time t1, the projection processing unit 16 generates the first LAMP_ENBL pulse. The count value of the counter 28 becomes 1. At time t1, the red light-emitting signal RED_LED1 remains at high level "1." At time t1, the D flip-flop 61 included in the signal conversion circuit 60 outputs the green light-emitting signal GRN_LED2, which goes high level "1," from the output terminal Q in response to the rising edge "↑" of the LAMP_ENBL pulse and the red light-emitting signal RED_LED1 going high level "1." In response to the rising edge "↑" of the green light-emitting signal GRN_LED2, the light source driving unit 17 causes the light source unit 18 to emit green light. Furthermore, the D flip-flop 63 outputs the red light-emitting signal RED_LED2, which goes low level "0," from the output terminal Q in response to the rising edge "↑" of the LAMP_ENBL pulse and the blue light-emitting signal BLU_LED1 going low level "0." This causes the light source driving unit 17 to instruct the light source unit 18 to turn off the red light. That is, the light source driving unit 17 instructs the light source unit 18 to switch from red light to green light at the start timing of the spoke period SP.

At time t2, the projection processing unit 16 sets the red light emission signal RED_LED1 to low level "0" and the green light emission signal GRN_LED1 to high level "1." The light source driving unit 17 does not use this information.

At time t3, the projection processing unit 16 generates a second LAMP_ENBL pulse. The count value of the counter 28 becomes 2. At time t3, the green light-emitting signal GRN_LED1 remains at high level "1." At time t3, the signal conversion circuit 60 uses the D flip-flop 62 to output from the output terminal Q the blue light-emitting signal BLU_LED2, which goes to high level "1" in response to the rising edge "↑" of the LAMP_ENBL pulse and the high level "1" of the green light-emitting signal GRN_LED1. In response to the rising edge "↑" of the blue light-emitting signal BLU_LED2, the light source driving unit 17 causes the light source unit 18 to emit blue light. In other words, the light source driving unit 17 controls the light source unit 18 to switch from green light to blue light in accordance with the start timing of the spoke period SP.

At time t4, the projection processing unit 16 sets the green light emission signal GRN_LED1 to low level "0" and the blue light emission signal BLU_LED1 to high level "1." The light source driving unit 17 does not use this information.

At time t5, the projection processing unit 16 generates a third LAMP_ENBL pulse. The count value of the counter 28 becomes 3. At time t5, the blue light-emitting signal BLU_LED1 remains at high level "1." At time t5, the signal conversion circuit 60, via the D flip-flop 63, outputs from the output terminal Q a red light-emitting signal RED_LED2 (e.g., second light-emitting signal) that goes high level "1" in response to the rising edge "↑" of the LAMP_ENBL pulse and the blue light-emitting signal BLU_LED1 (e.g., first light-emitting signal) going high level "1." In response to the rising edge "↑" of the red light-emitting signal RED_LED2, the light source driving unit 17 causes the light source unit 18 to emit red light. That is, the light source driving unit 17 controls the light source to switch from blue light (e.g., first color light) to red light (e.g., second color light) in accordance with the start timing of the spoke period SP.

At time t6, the projection processing unit 16 sets the blue light-emitting signal BLU_LED1 to low level "0" and the red light-emitting signal RED_LED1 to high level "1." Time t6 marks the end of one frame.

After three LAMP_ENBL pulses are generated, the index sensor 36 activates the index signal. When the index signal is activated, the light source driver 17 clears the count value of the counter 28 to zero. The R, G, and B light emission processes are then repeated.

[3] Effects of the embodiment According to the embodiment, the projection device 10 can start the process of switching from a first color light to a second color light different from the first color at the beginning of the spoke period SP (i.e., at the timing when the LAMP_ENBL pulse rises). By starting the switching process earlier than in the comparative example, it becomes possible to use a light source with a slow startup response (taking time to reach maximum brightness). Note that by using this patent, the spoke period can theoretically be halved.

In addition, the brightness of monochromatic light can be improved within one frame, thereby improving the display characteristics of the projection device 10.

In addition, during the spoke period SP, it becomes possible to increase the light emission period of one of the RGB colors. This improves the display characteristics of RGB monochromatic colors.

[4] Other Examples In this embodiment, one functional block may be configured as a single piece of hardware, a single piece of software, or a combination thereof.

The functional configuration in this embodiment is realized by a processor that executes arithmetic processing. Processors that can be used in this embodiment include those configured as individual processing devices such as single processors, multiprocessors, and multicore processors, as well as those that combine these processing devices with processing circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays).

When a series of processes is performed by software, the programs that make up that software are installed onto a computer or other device from a network or recording medium.

The computer may be a computer built into dedicated hardware. Alternatively, the computer may be a computer capable of performing various functions by installing various programs, such as a general-purpose personal computer.

Recording media containing such programs include not only removable media distributed separately from the device itself to provide the program to the user, but also recording media provided to the user in a state where it is pre-installed in the device itself. Removable media include, for example, magnetic disks, optical disks, and magneto-optical disks. Optical disks include, for example, CD-ROMs (Compact Disk-Read Only Memory), DVDs (Digital Versatile Disks), and Blu-ray (registered trademark) Discs. Magneto-optical disks include, for example, MDs (Mini-Disks). Recording media provided to the user in a state where it is pre-installed in the device itself include, for example, semiconductor memory included in the storage unit on which the program is recorded.

The steps of writing a program to be recorded on a recording medium include not only processes that are performed chronologically in the order specified, but also processes that are not necessarily performed chronologically but are executed in parallel or individually.

Note that while the embodiments of the present invention have been described using a rising edge D flip-flop as an example, if the output signal of the LAMP_ENBL pulse is inverted, a falling edge D flip-flop may also be used.

The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the various embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the multiple elements disclosed. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention.

The inventions described in the original claims of this application are as follows:

[Claim 1]
A projection device comprising: a light source driver that controls a light source unit to emit light of a second color different from the first color based on a first light emission signal for emitting light of the first color.

[Claim 2]
the light source driving unit outputs a pulse signal whose output state changes for each spoke period for switching the color of light, and a second light emission signal for causing the light source unit to emit the second color light, based on the first light emission signal.
The projection device according to claim 1 .

[Claim 3]
the light source drive unit outputs the second light emission signal that rises when the pulse signal rises and the first light emission signal is at a high level, and controls the light source unit to emit the second color light based on the output second light emission signal.
3. The projection device according to claim 2.

[Claim 4]
the light source driver includes a rising edge type D flip-flop;
an input terminal of the D flip-flop receives the first light-emitting signal;
The clock terminal of the D flip-flop receives the pulse signal,
The projection device according to claim 2 or 3, wherein the D flip-flop outputs the second light emission signal from an output terminal.

[Claim 5]
the light source driving unit outputs the second light emission signal that rises not at the center timing of the spoke period but at the start timing of the spoke period.
5. The projection device according to claim 3 or 4.

[Claim 6]
The light emitted by the light source unit is three segments of blue light, red light, and green light.
6. A projection device according to claim 1.

[Claim 7]
The computer
controlling the light source unit to emit light of a second color different from the first color based on a first light emission signal for emitting light of the first color;
Projection method.

[Claim 8]
On the computer,
controlling the light source unit to emit light of a second color different from the first color based on a first light emission signal for emitting light of the first color;
A program that executes a process.

10... Projection device 11... Input/output connector 12... Input/output interface 13... Bus 14... Image conversion unit 14... Light source unit 15... VRAM
16...Projection processing unit 17...Light source driving unit 18...Light source unit 19...Micro mirror element 20...Mirror 21...Projection lens unit 22...Audio processing unit 23...Speaker 24...CPU
25...Memory section 26...Operation section 27...Power supply circuit 28...Counter 31...Semiconductor laser 32...LED
33...mirror 34...dichroic mirror 35...phosphor wheel 36...index sensor 37...motor 38...mirror 39...mirror 40...dichroic mirror 41...integrator 42...mirror 50...substrate 51...bearing 52...transmission area 53...reflective area 60...signal conversion circuits 61 to 63...D flip-flop

Claims (6)

a light source driver including a plurality of D flip-flops;
a first D flip-flop among the plurality of D flip-flops receives a first light emission signal at an input terminal for emitting light of a first color, and when receives an enable signal at a clock terminal for switching from emitting the first color to emitting a second color during a spoke period, outputs a second light emission signal at an output terminal for emitting the second color, and controls a light source unit to emit light of the second color based on the output second light emission signal . the light source driving unit outputs the second light emission signal that rises when the enable signal rises and the first light emission signal is at a high level, and controls the light source unit to emit the second color light based on the output second light emission signal.
The projection device according to claim 1 . the light source driving unit outputs the second light emission signal that rises not at the center timing of the spoke period but at the start timing of the spoke period.
3. The projection device according to claim 1 or 2. The light emitted by the light source unit is three segments of blue light, red light, and green light.
4. The projection device according to claim 1 . The computer
a first D flip-flop among the plurality of D flip-flops of the light source drive unit receives at an input terminal a first light-emitting signal for emitting light of a first color and at a clock terminal an enable signal for switching from light emission of the first color to light emission of a second color during a spoke period, the first D flip-flop outputs from an output terminal a second light-emitting signal for emitting light of the second color, and controls the light source unit to emit light of the second color based on the output second light-emitting signal ;
Projection method. On the computer,
a first D flip-flop among the plurality of D flip-flops of the light source drive unit receives at an input terminal a first light-emitting signal for emitting light of a first color and at a clock terminal an enable signal for switching from light emission of the first color to light emission of a second color during a spoke period, outputs from an output terminal a second light-emitting signal for emitting light of the second color, and controls the light source unit to emit light of the second color based on the output second light-emitting signal ;
A program that executes a process.