Projector and projection method thereof

A projector and a projection method are provided. The projector is coupled to a display card and includes a light source, a light valve, a projection lens, and a processor. The light source provides an illumination beam. The light valve converts the illumination beam into an image beam. The projection lens projects the image beam to the outside of the projector to form an imaged image. The processor receives an input image signal from the display card, and generates a control signal corresponding to the input image signal according to a refresh rate of the input image signal. When the refresh rate is greater than a threshold, the imaged image has a first resolution. When the refresh rate is less than the threshold, the light valve performs a pixel shifting operation, so that the imaged image has a second resolution. The first resolution is less than the second resolution.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serial no. 201910751803.3, filed on Aug. 15, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a projector and a projection method, and in particular, to a projector having a plurality of projection modes, and a projection method.

2. Description of Related Art

With the evolution of science and technology, high-resolution (e.g., 4K) display devices (e.g., projectors) have been developed successively. The high-resolution projectors can greatly enhance the visual experiences of users. On the other hand, as the influence of games on the economy and society has gradually increased, the electronic sports industry has emerged. For the application of electronic sports, the magnitude of resolution of a display frame is not the main consideration, but the response speed and frame correctness of the display device are the most important considerations. However, there is currently no single projector capable of meeting the demands of high resolution and high response speed simultaneously.

SUMMARY OF THE INVENTION

In view of this, the invention provides a projector and a projection method, where an image with high resolution and high response speed can be provided through a single projector.

The invention provides a projector, coupled to a display card. The projector includes a light source, a light valve, a projection lens, and a processor. The light source is configured to provide an illumination beam. The light valve is provided on a transmission path of the illumination beam and configured to convert the illumination beam into an image beam according to a control signal. The projection lens is provided on a transmission path of the image beam, and configured to project the image beam to the outside of the projector to form an imaged image. The processor is coupled to the light valve, and receives an input image signal from the display card. The processor generates the control signal corresponding to the input image signal according to a refresh rate of the input image signal. When the refresh rate is greater than a threshold, the imaged image has a first resolution. When the refresh rate is less than the threshold, the light valve performs a pixel shifting operation, so that the imaged image has a second resolution. The first resolution is less than the second resolution.

The invention provides a projection method, applicable to a projector. The projector is coupled to a display card. The projector includes a light source, a light valve, a projection lens, and a processor. The processor is coupled to the light valve. The projection method includes: providing, by the light source, an illumination beam; converting the illumination beam into an image beam according to a control signal by providing the light valve on a transmission path of the illumination beam; projecting the image beam to the outside of the projector to form an imaged image by providing the projection lens on a transmission path of the image beam; and receiving, by the processor, an input image signal from the display card, and generating, by the processor, the control signal corresponding to the input image signal according to a refresh rate of the input image signal. When the refresh rate is greater than a threshold, the imaged image has a first resolution. When the refresh rate is less than the threshold, the light valve performs a pixel shifting operation, so that the imaged image has a second resolution. The first resolution is less than the second resolution.

Based on the above, according to the projector and the projection method of the invention, a processor of the projector generates the control signal corresponding to the input image signal according to the refresh rate of the input image signal. The light valve of the projector converts the illumination beam into the image beam according to the control signal, and the projection lens of the projector projects the image beam to the outside of the projector to form the imaged image. When the refresh rate is greater than a threshold, the imaged image has a first resolution. When the refresh rate is less than the threshold, the light valve performs the pixel shifting operation, so that the imaged image has a second resolution. The first resolution is less than the second resolution. In this way, high-definition imaging or high-refresh rate imaging can be performed according to a determination result without increasing the resolution specification of the light valve, so that the light valve of the same specification achieves more benefits.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1is a block diagram of a projector100according to an embodiment of the invention.

Referring toFIG. 1, the projector100is coupled to a display card (not shown in the figure), and includes a light source110, a light valve120, a projection lens130, a processor140, a buffer150, and a storage device160. The display card refers to the source of an image signal. The display card is, for example, provided in a personal computer or a portable computer, and coupled to the projector100by the personal computer or the portable computer. The so-called coupling may be defined as transfer of an electrical signal or data. The processor140is coupled to the light valve120, the buffer150and the storage device160. The light source110provides an illumination beam L1. The light valve120is provided on a transmission path of the illumination beam L1, and controls, according to a control signal of the processor140, the light valve120to convert the illumination beam L1into an image beam L2. The projection lens130is provided on a transmission path of the image beam L2, and projects the image beam L2to the outside of the projector100to form an imaged image20.

The light source110is, for example, a bulb, a light emitting diode (LED), a laser diode (LD), or other similar light emitting elements. The light valve120is, for example, a digital micromirror device (DMD), a reflective liquid crystal on silicon (LCOS) device, a transparent liquid crystal panel, or other similar elements. The processor140is, for example, a micro controller unit (MCU), or other programmable general-purpose or special-purpose microprocessors, digital signal processors (DSP), programmable controllers, application specific integrated circuits (ASIC), programmable logic devices (PLD), or other similar devices or processing software or control software, but the invention is not limited to the above hardware or software. The storage device160is, for example, a programmable read only memory (PROM), an electronically erasable programmable read only memory (EEPROM), or other similar elements. In the present embodiment, the buffer150is, for example, a memory in which output or input data is temporarily placed. The buffer150is provided outside the processor140and coupled to the processor140, but the invention is not limited thereto. In another embodiment, the buffer150may also be provided in the processor140or in the storage device160.

The processor140may receive an input image signal from a display card (not shown) provided outside the projector100, and generate a control signal corresponding to the input image signal according to a refresh rate of the input image signal. When the refresh rate is greater than a threshold, the imaged image20has a first resolution. When the refresh rate is less than the threshold, the light valve120performs a pixel shifting operation, so that the imaged image20has a second resolution. The first resolution is less than the second resolution. In detail, the light valve120may use the same light valve refresh rate such that the imaged image20has a first resolution or a second resolution.

In an embodiment, when the processor140receives an input image signal, the processor140may convert the resolution of the input image signal into a preset resolution (e.g., 1080P resolution) in advance. When the processor140determines that the refresh rate (e.g., 60 Hz) of the input image signal is less than a threshold (e.g., 100 Hz), the processor140may instruct the light valve120to perform a pixel shifting operation. The pixel shifting operation includes resolution up-sampling.FIG. 2is a schematic diagram showing an example of resolution up-sampling according to an embodiment of the invention. Referring toFIG. 2, the processor140may instruct the light valve120to cooperate with the projection lens130to shift an original image pixel210of a 1080P-resolution image diagonally by half a pixel to obtain a displacement image pixel220, so that the resolutions in a horizontal direction and a vertical direction are simultaneously doubled to obtain a 4K-resolution image. For example, the pixel shifting operation may be implemented by digital or optical technologies known to those skilled in the art such as expanded pixel resolution (XPR), pixel shift (e-shift), or 4K enhancement.

Specifically, the pixel shifting operation may include: dividing each frame of the input image signal into a plurality of sub-frames, and projecting the sub-frames with a displacement shift by half a pixel.FIG. 3is a schematic diagram showing an example of a pixel shifting operation according to an embodiment of the invention. Referring toFIG. 3, the pixel shifting operation includes: dividing a 4K-resolution and 60 Hz-refresh rate frame300into a sub-frame310, a sub-frame320, a sub-frame330, and a sub-frame340, and sequentially projecting the sub-frame310, the sub-frame320, the sub-frame330, and the sub-frame340with 1080P resolution and 240 Hz. The projected sub-frame320is shifted rightwards by half a pixel from the sub-frame310. The projected sub-frame330is shifted downwards by half a pixel from the sub-frame320. The projected sub-frame340is shifted leftwards by half a pixel from the sub-frame330. The projected sub-frame310is shifted upwards by half a pixel from the sub-frame340. Due to the effect of persistence of vision, the sub-frame310, the sub-frame320, the sub-frame330, and the sub-frame340that are sequentially displayed at a refresh rate of 240 Hz can bring a visual effect of 4K resolution to users. Although the resolution of the imaged image20is quadrupled by the pixel shifting operation by the light valve120in the present embodiment, the invention is not limited thereto. In other embodiments, the resolution of the imaged image20may be increased to other multiples (e.g., double or octuple) by other operations on the pixel through the light valve120.

When the processor140determines that the refresh rate (e.g., 240 Hz) of the input image signal is larger than a threshold (e.g., 100 Hz), the processor140may instruct the light valve120to project the 1080P-resolution imaged image20at a refresh rate of 240 Hz by means of the projection lens130without performing the pixel shifting operation. In this way, when the imaged image20has a 1080P resolution (first resolution) or a 4 k resolution (or second resolution), the imaged image20is projected at the same light valve refresh rate (e.g., 240 Hz). Specifically, the light valve120is configured to convert the illumination beam L1into the image beam L2. Each image beam L2may correspond to a frame or a sub-frame. The light valve refresh rate may refer to the number of frames which can be imaged by the light valve120per second.

In an embodiment, when the refresh rate is greater than the threshold and the refresh rate is greater than a predetermined rate, the processor140obtains, from the buffer150of the projector100, a latest frame of the input image signal received from the display card, and transmits the latest frame to the light valve120. Specifically, the refresh rate of the input image signal transmitted by the display card may be greater than a maximum refresh rate (i.e., predetermined rate) that can be supported by the light valve120. In this case, the processor140may perform a fast synchronization operation. Specifically, when the refresh rate (e.g., 300 Hz) of the input image signal is greater than a threshold (e.g., 100 Hz) and the refresh rate (e.g., 300 Hz) of the input image signal is greater than a predetermined rate (e.g., 240 Hz, or referred to as a maximum refresh rate that can be supported by the light valve120), the processor140obtains, from the buffer150of the projector100, a latest frame of the input image signal received from the display card every 1/240 seconds, and transmits the latest frame to the light valve120.

In an embodiment, the storage device160may store identification data. The identification data is, for example, extended display identification data (EDID). The identification data includes at least a high-definition mode and a high-refresh rate mode. When the processor140determines that the refresh rate of the input image signal is greater than the threshold, the processor140may access configuration data corresponding to the high-refresh rate mode, and instruct the light valve120to cooperate with the projection lens130to project an imaged image20with a high refresh rate (e.g., 240 Hz). When the processor140determines that the refresh rate of the input image signal is less than the threshold, the processor140may access configuration data corresponding to the high-definition mode, and instruct the light valve120to perform a pixel shifting operation to project an imaged image20with high definition (e.g., 4K resolution) by cooperating with the projection lens130.

FIG. 4is a flow chart of a projection method according to an embodiment of the invention.

Referring toFIG. 4, in step S401, a light source provides an illumination beam.

In step S402, the illumination beam is converted into an image beam according to a control signal by providing a light valve on a transmission path of the illumination beam.

In step S403, the image beam is projected to the outside of the projector to form an imaged image by providing a projection lens on a transmission path of the image beam.

In step S404, a processor receives an input image signal from a display card, and the processor generates the control signal corresponding to the input image signal according to a refresh rate of the input image signal.

In step S405a, when the refresh rate is greater than a threshold, the imaged image has a first resolution. In step S405b, when the refresh rate is less than the threshold, the light valve performs a pixel shifting operation, so that the imaged image has a second resolution, and the first resolution is less than the second resolution.

Based on the above, according to the projector and the projection method of the invention, a processor of the projector generates the control signal corresponding to the input image signal according to the refresh rate of the input image signal. The light valve of the projector converts the illumination beam into the image beam according to the control signal, and the projection lens of the projector projects the image beam to the outside of the projector to form the imaged image. When the refresh rate is greater than a threshold, the imaged image has a first resolution. When the refresh rate is less than the threshold, the light valve performs a pixel shifting operation, so that the imaged image has a second resolution. The first resolution is less than the second resolution. According to the projector and the projection method of the invention, a high-definition mode and a high-refresh rate mode may be automatically switched according to the refresh rate of the input image signal, so that a single projector meets different demands of users.