Projection devices and projection methods applicable to liquid crystal silicon-coated panels

Abstract

The projection apparatus disclosed herein includes a light source, a liquid crystal silicon-coated panel, and circuitry. The circuitry acquires a target image and generates two content images. The target image contains a target pattern, and each content image includes a copy of the target pattern. When a computer-generated hologram algorithm is executed, these copy patterns are off-axis displaced to the same coordinates to generate a phase image. The liquid crystal silicon-coated panel is driven to display a reconstructed image at a reconstruction distance based on the phase image.

Description

Technical Field

[0001] This disclosure relates to projection devices capable of reducing speckle noise, including liquid crystal silicon-coated panels. Background Technology

[0002] Liquid crystal on silicon (LCoS) displays are miniaturized diffraction active array liquid crystal displays that achieve image formation by forming a liquid crystal layer on a silicon substrate. Originally developed for projection televisions, LCoS displays are now used for wavelength selective switching, structured illumination, near-eye displays, and light pulse shaping. When used as a holographic display, LCoS images are formed using the principle of optical diffraction, achieved through constructive and destructive interference. An LCoS display has multiple pixels; when a laser line is incident on the LCoS display, each pixel can change the phase of the laser line, reconstructing a diffraction image at a specific distance. The constructive and destructive interference mentioned above can produce bright and dark spots; reducing these bright and dark spots is a concern for those skilled in the art. Summary of the Invention

[0003] Embodiments of this disclosure provide a projection device including a light source, a liquid crystal silicon-coated panel, and circuitry. The light source provides light. The circuitry acquires a target image, which includes a first target pattern. The circuitry generates a first content image and a second content image based on the target image, wherein the first content image includes a first copy of the first target pattern, and the second content image includes a second copy of the first target pattern, the coordinates of the first copy being different from the coordinates of the second copy. The circuitry also sets a first off-axis displacement of the first copy and a second off-axis displacement of the second copy, such that the coordinates of the first copy after displacement are the same as the coordinates of the second copy. The circuitry also executes a computer-generated hologram (CGH) algorithm to generate a phase image based on the first content image, the first off-axis displacement, the second content image, the second off-axis displacement, the wavelength of the light, and a first reconstruction distance. The liquid crystal silicon-coated panel receives the light, and the circuitry drives the liquid crystal silicon-coated panel to display the first reconstructed image at the first reconstruction distance based on the phase image.

[0004] In some embodiments, the first off-axis displacement is in a first direction, and the circuit is used to gradually increase the intensity of the first replicated pattern along the first direction.

[0005] In some embodiments, the second off-axis displacement is in a second direction, and the circuit is used to gradually increase the intensity of the second replicated pattern along the second direction.

[0006] In some embodiments, the target pattern is located at a first coordinate, which is within the range corresponding to the liquid crystal silicon-coated panel. The circuit sets a first off-axis displacement such that the coordinates of the first replicated pattern after displacement are different from the first coordinate and outside the range corresponding to the liquid crystal silicon-coated panel.

[0007] In some embodiments, the liquid crystal silicon-coated panel includes a plurality of pixels, and the circuitry is used to determine the upper limit of the first off-axis displacement based on the first reconstruction distance, wavelength, and pixel size.

[0008] In some embodiments, the target image further includes a second target pattern. The circuit is configured to generate a third content image and a fourth content image based on the target image. The third content image includes a third copy of the second target pattern, and the fourth content image includes a fourth copy of the second target pattern. The coordinates of the third copy are different from the coordinates of the fourth copy. The circuit is further configured to set a third off-axis displacement of the third copy and a fourth off-axis displacement of the fourth copy, such that the coordinates of the third copy after displacement are the same as the coordinates of the fourth copy. The circuit is further configured to execute a computer-generated hologram algorithm based on a second reconstruction distance, so that the liquid crystal silicon-coated panel displays a second reconstructed image at the second reconstruction distance, and the second reconstructed image corresponds to the second target pattern.

[0009] From another perspective, embodiments of this disclosure propose a projection method applicable to a liquid crystal silicon-coated panel, which is executed by a circuit. The projection method includes: acquiring a target image; generating a first content image and a second content image based on the target image, wherein the target image includes a first target pattern, the first content image includes a first copy pattern of the first target pattern, and the second content image includes a second copy pattern of the first target pattern, the coordinates of the first copy pattern being different from the coordinates of the second copy pattern; setting a first off-axis displacement of the first copy pattern and a second off-axis displacement of the second copy pattern such that the coordinates of the first copy pattern after displacement are the same as the coordinates of the second copy pattern after displacement; executing a computer-generated hologram (CGH) algorithm to generate a phase image based on the first content image, the first off-axis displacement, the second content image, the second off-axis displacement, the wavelength of a light source, and a first reconstruction distance; and driving the liquid crystal silicon-coated panel according to the phase image, the liquid crystal silicon-coated panel receiving light and displaying the first reconstructed image at the first reconstruction distance.

[0010] In some embodiments, the first off-axis displacement is in a first direction, and the projection method further includes gradually increasing the intensity of the first replicated pattern along the first direction.

[0011] In some embodiments, the second off-axis displacement is in a second direction, and the projection method further includes gradually increasing the intensity of the second replicated pattern along the second direction.

[0012] In some embodiments, the target pattern is located at a first coordinate, which is within the range corresponding to the liquid crystal silicon-coated panel. The projection method further includes setting a first off-axis displacement such that the coordinates of the first replicated pattern after displacement are different from the first coordinate and outside the range corresponding to the liquid crystal silicon-coated panel.

[0013] In some embodiments, the liquid crystal silicon-coated panel includes a plurality of pixels, and the projection method further includes determining an upper limit of the first off-axis displacement based on a first reconstruction distance, wavelength, and pixel size.

[0014] In some embodiments, the target image further includes a second target pattern, and the projection method further includes generating a third content image and a fourth content image based on the target image, wherein the third content image includes a third copy pattern of the second target pattern, and the fourth content image includes a fourth copy pattern of the second target pattern, and the coordinates of the third copy pattern are different from the coordinates of the fourth copy pattern; setting a third off-axis displacement of the third copy pattern and a fourth off-axis displacement of the fourth copy pattern, such that the coordinates of the third copy pattern after displacement are the same as the coordinates of the fourth copy pattern after displacement; and executing a computer-generated hologram algorithm based on a second reconstruction distance, so that the liquid crystal silicon-coated panel displays the second reconstructed image at the second reconstruction distance. Attached Figure Description

[0015] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings.

[0016] Figure 1 This is a schematic diagram illustrating a projection device according to one embodiment.

[0017] Figure 2 This is a schematic diagram illustrating the generation of a reconstructed image according to one embodiment.

[0018] Figure 3 The reconstructed image is shown according to one embodiment.

[0019] Figure 4 This is a schematic diagram illustrating off-axis displacement according to one embodiment.

[0020] Figure 5 This is a schematic diagram illustrating the generation of two reconstructed images according to one embodiment.

[0021] Figure 6 This is a flowchart illustrating a projection method according to one embodiment.

[0022] Explanation of reference numerals in the attached figures:

[0023] 110: Circuit

[0024] 120: Liquid crystal silicon-coated panel

[0025] 130: Light source

[0026] 132: Light

[0027] 134: Imaging X-ray

[0028] 140: Optical beam splitter

[0029] 150: Projection lens

[0030] 160: Reconstructed Image

[0031] 170: Reconstruction Distance

[0032] 210: Target Image

[0033] 211: Target Pattern

[0034] 220: First Content Image

[0035] 221,231: Copy pattern

[0036] 222,232: Off-axis displacement

[0037] 230: Second Content Image

[0038] 240: Algorithm for Computer-Generated Holograms

[0039] 250: Phase Image

[0040] 310, 320: Reconstructed Images

[0041] θ: Angle

[0042] 511: Target Pattern

[0043] 520: Third Content Image

[0044] 521, 531: Copy pattern

[0045] 522, 532: Off-axis displacement

[0046] 530: Fourth Content Image

[0047] 550: Phase Image

[0048] 560: Reconstructed Images

[0049] 570: Reconstruction Distance

[0050] 601-604: Steps Detailed Implementation

[0051] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence; they are merely used to distinguish elements or operations described using the same technical terms.

[0052] Figure 1 This is a schematic diagram illustrating a projection device according to one embodiment. Please refer to... Figure 1 The projection device includes circuitry 110, a liquid crystal silicon-coated panel 120, a light source 130, a beam splitter device 140, and a projection lens 150. Circuitry 110 can be designed using hardware description languages ​​(HDL) or any digital circuit design method, or it can be implemented using a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), or an application-specific integrated circuit (ASIC). The light source 130 is, for example, a laser source, used to emit light 132 to the beam splitter device 140. The beam splitter device 140 is, for example, a polarizing beamsplitter (PBS), used to reflect the light 132 with a first polarization back to the liquid crystal silicon-coated panel 120. The liquid crystal silicon-coated panel 120 includes multiple pixels, each pixel being used to change the phase of light 132. Circuit 110 drives the liquid crystal silicon-coated panel 120 according to a phase image, thereby converting the light 132 into image rays 134. A beam splitter 140 receives the image rays 134 and transmits the image rays 134 with a second polarization to a projection lens 150. For example, the first polarization is S-polarization, and the second polarization is P-polarization, but this disclosure is not limited thereto. The phase image is also referred to as a Kinoform. The projection lens 150 includes, for example, a collimator and one or more lenses. The image rays 134 emitted from the projection lens 150 can form a reconstructed image 160, which can be projected onto a screen at a reconstruction distance 170, a human eye, a translucent material, or other suitable material, but this disclosure is not limited thereto.

[0053] In this embodiment, when a target image is to be displayed, circuit 110 copies the pattern in the target image to generate multiple content images, and overlaps the patterns in these content images at the same position by means of off-axis operation, thereby reducing speckles in the reconstructed image 160. The operation of circuit 110 is described below.

[0054] Figure 2 This is a schematic diagram illustrating the generation of a reconstructed image according to one embodiment. Please refer to... Figure 2First, a target image 210 is obtained. This target image 210 includes a target pattern 211, which can be text, numbers, symbols, images, or a combination thereof. This disclosure does not limit the content of the target pattern 211. Next, a first content image 220 and a second content image 230 are generated based on the target image 210. The first content image 220 includes a copy pattern 221 of the target pattern 211, meaning that the shape and color of the copy pattern 221 are the same as those of the target pattern 211. Similarly, the second content image 230 also includes a copy pattern 231 of the target pattern 211. In particular, the coordinates of the copy pattern 221 are different from the coordinates of the copy pattern 231. In this embodiment, the target pattern 211 is moved to the left to generate the copy pattern 221, and the target pattern 211 is moved to the right to generate the copy pattern 231.

[0055] Specifically, an off-axis shift 222 is set for the copied pattern 221, and an off-axis shift 232 is set for the copied pattern 231, ensuring that the coordinates of the copied pattern 221 after the shift are the same as those of the copied pattern 231 after the shift. For example, if the coordinates of the target pattern 211 are (x, y), the coordinates of the copied pattern 221 are (xa, y), and the coordinates of the copied pattern 231 are (x+a, y), the off-axis shift 222 is (+a, -b), therefore the coordinates of the copied pattern 221 after the shift are (x, yb); the off-axis shift 232 is (-a, -b), therefore the coordinates of the copied pattern 231 after the shift are (x, yb), where x, y, a, and b are real numbers. It is important to note that the coordinates (x, yb) of the copied pattern 221 after the shift are different from the coordinates (x, y) of the target pattern 211. In some embodiments, the coordinates (x, y) are located within the range corresponding to the liquid crystal silicon-coated panel 120; however, the coordinates (x, yb) of the replicated pattern 221 after displacement are outside the range corresponding to the liquid crystal silicon-coated panel 120. For example, (yb) < 0 indicates that the Y coordinate exceeds the range of the liquid crystal silicon-coated panel 120. This is because there are some uncontrollable optical effects in the spacing between pixels, which can affect the imaging within the panel area. Therefore, in this embodiment, the displacement coordinates are set to be outside the panel area.

[0056] Next, the first content image 220, off-axis displacement 222, second content image 230, off-axis displacement 232, the wavelength of the aforementioned light ray 132, and the reconstruction distance 170 can be input into a computer-generated hologram (CGH) algorithm 240 to generate a phase image 250. The CGH algorithm can calculate the value of each pixel in the phase image 250 based on the principles of constructive and destructive interference. Any suitable CGH algorithm can be used here, and this disclosure is not limited thereto. The pixels on the phase image 250 correspond to the pixels on the liquid crystal silicon-coated panel 120, thereby changing the phase of the light ray passing through the corresponding pixel. The liquid crystal silicon-coated panel 120 can then be driven based on this phase image 250 to display the reconstructed image 160.

[0057] Generally, the reconstructed image 160 has speckles (which may be bright spots or dark spots). In this embodiment, since the copied pattern 221 and the copied pattern 231 are overlapped by off-axis means, the speckle noise in the reconstructed image 160 is reduced. Figure 3 The reconstructed image is shown according to one embodiment. Please refer to... Figure 3 The reconstructed image 310 is generated using existing methods, that is, the corresponding phase image is generated directly from the target image 210. On the other hand, the reconstructed image 320 is generated using the method described in the above embodiment, from... Figure 3 As can be seen, the speckles in reconstructed image 320 have been suppressed compared to reconstructed image 310. The degree of speckle suppression can be measured by the standard deviation of pixel intensity; in this example, the standard deviation of reconstructed image 310 is 0.2, while the standard deviation of reconstructed image 320 is 0.15.

[0058] Figure 4 This is a schematic diagram illustrating off-axis displacement according to one embodiment. Please refer to... Figure 4 Taking the replicated pattern 221 as an example, the corresponding off-axis displacement 222 has an upper limit, which is determined by the off-axis angle θ and the reconstruction distance 170. The angle θ is limited by the pixel size and the wavelength of the light. In some embodiments, the upper limit of the off-axis displacement 222 can be determined based on the reconstruction distance 170, the wavelength of the light, and the pixel size. For example, when the wavelength is 520nm and the pixel size is 4.25μm, the maximum value of the angle θ is 7 degrees, from which the corresponding upper limit can be calculated.

[0059] In addition, when the replicated pattern 221 is displaced off-axis, the intensity decreases more with distance, so compensation can be made based on the displacement distance. For example, if the off-axis displacement 222 is in the first direction, the intensity of the replicated pattern 221 can be gradually increased along the first direction, for example, through a linear function. In this example, the intensity of the number "3" will be compensated more than that of the number "1". Similarly, if Figure 2 If the off-axis displacement 232 of the replicated pattern 231 is in the second direction, then the intensity of the replicated pattern 232 can be gradually increased along the second direction.

[0060] In some embodiments, if the target image contains multiple target patterns, images at different distances can be reconstructed using the methods described above. For example, please refer to... Figure 5 ,exist Figure 5 In this embodiment, the target image 210 further includes a target pattern 511, and the circuit 110 also generates a third content image 520 and a fourth content image 530. The third content image 520 includes a copy pattern 521 of the target pattern 511, and the fourth content image 530 includes a copy pattern 531 of the target pattern 511, but the coordinates of the copy pattern 521 are different from the coordinates of the copy pattern 531. Similarly, the circuit 110 also sets an off-axis displacement 522 for the copy pattern 521 and an off-axis displacement 532 for the copy pattern 531, so that the coordinates of the copy pattern 521 after displacement are the same as the coordinates of the copy pattern 531 after displacement. When executing the computer-generated hologram algorithm, in addition to the content images 220, 230, 520, and 530, reconstruction distances 170 and 570 are also set to generate a phase image 550, which causes the reconstructed image 160 to be imaged at reconstruction distance 170, and the reconstructed image 560 to be imaged at reconstruction distance 570. For example, a reconstruction distance of 170 could be 5 meters, while a reconstruction distance of 570 could be 10 meters. In this way, the user can see two target patterns at different depths of field.

[0061] The above method reduces speckle noise through spatial multiplexing. In some embodiments, this spatial multiplexing can also be combined with temporal multiplexing. For example, when there is only one liquid crystal silicon-coated panel 120, temporal multiplexing must be used to display red, green, and blue images separately. These three images can also use the above-mentioned spatial multiplexing to reduce speckle noise. Alternatively, when there are three liquid crystal silicon-coated panels 120 displaying red, green, and blue images respectively, the images displayed on each panel can also use spatial multiplexing technology.

[0062] Figure 6 This is a flowchart illustrating a projection method according to one embodiment. Please refer to... Figure 6In step 601, a target image is acquired, and a first content image and a second content image are generated based on the target image. The target image includes a first target pattern, the first content image includes a first copy of the first target pattern, and the second content image includes a second copy of the first target pattern. The coordinates of the first copy are different from the coordinates of the second copy. In step 602, a first off-axis displacement of the first copy and a second off-axis displacement of the second copy are set, such that the coordinates of the first copy after displacement are the same as the coordinates of the second copy after displacement. In step 603, a computer-generated hologram algorithm is executed to generate a phase image based on the first content image, the first off-axis displacement, the second content image, the second off-axis displacement, the wavelength of the light, and a first reconstruction distance. In step 604, a liquid crystal silicon-coated panel is driven based on the phase image. The liquid crystal silicon-coated panel receives light and displays the first reconstructed image at the first reconstruction distance. However, Figure 6 Each step has been explained in detail above and will not be repeated here. It is worth noting that... Figure 6 Each step can be implemented as multiple program codes or circuits, but this invention is not limited thereto. Furthermore, Figure 6 The method can be used in conjunction with the above embodiments, or it can be used alone. In other words, Figure 6 Other steps can also be added between the various steps.

[0063] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes and modifications without departing from the concept and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A projection device, comprising: A light source, used to provide a ray of light; A liquid crystal silicon-coated panel; as well as A circuit is used to acquire a target image, the target image including a first target pattern. The circuit is used to generate a first content image and a second content image based on the target image. The first content image includes a first copy of the first target pattern, and the second content image includes a second copy of the first target pattern. The coordinates of the first copy are different from the coordinates of the second copy. The circuit is used to set a first off-axis displacement of the first replicated pattern and a second off-axis displacement of the second replicated pattern, such that the coordinates of the first replicated pattern after displacement are the same as the coordinates of the second replicated pattern after displacement. The circuit is used to execute a computer-generated hologram algorithm to generate a phase image based on the first content image, the first off-axis displacement, the second content image, the second off-axis displacement, the wavelength of the light, and a first reconstruction distance. The liquid crystal silicon-coated panel receives the light, and the circuit is used to drive the liquid crystal silicon-coated panel to display a first reconstructed image at the first reconstruction distance according to the phase image.

2. The projection device of claim 1, wherein the first off-axis displacement is in a first direction, and the circuit is used to gradually increase the intensity of the first replicated pattern along the first direction.

3. The projection device of claim 2, wherein the second off-axis displacement is in a second direction, and the circuit is used to gradually increase the intensity of the second replicated pattern along the second direction.

4. The projection device as claimed in claim 2, wherein the target pattern is located at a first coordinate, the first coordinate is located within the range corresponding to the liquid crystal silicon-coated panel, and the circuit sets the first off-axis displacement such that the coordinate of the first replicated pattern after displacement is different from the first coordinate and is outside the range corresponding to the liquid crystal silicon-coated panel.

5. The projection device of claim 1, wherein the liquid crystal silicon-coated panel includes a plurality of pixels, and the circuit is configured to determine the upper limit of the first off-axis displacement based on the first reconstruction distance, the wavelength, and the size of the pixels.

6. The projection apparatus of claim 1, wherein the target image further comprises a second target pattern, the circuit being configured to generate a third content image and a fourth content image based on the target image, wherein the third content image comprises a third copy pattern of the second target pattern, the fourth content image comprises a fourth copy pattern of the second target pattern, and the coordinates of the third copy pattern are different from the coordinates of the fourth copy pattern. The circuit is used to set the third off-axis displacement of the third replicated pattern and the fourth off-axis displacement of the fourth replicated pattern, such that the coordinates of the third replicated pattern after displacement are the same as the coordinates of the fourth replicated pattern after displacement. The circuit is also used to execute the computer-generated hologram algorithm according to a second reconstruction distance, so that the liquid crystal silicon-coated panel displays a second reconstructed image at the second reconstruction distance, and the second reconstructed image corresponds to the second target pattern.

7. A projection method applicable to a liquid crystal silicon-coated panel, the projection method being executed by a circuit, the projection method comprising: A target image is acquired, and a first content image and a second content image are generated based on the target image. The target image includes a first target pattern, the first content image includes a first copy pattern of the first target pattern, and the second content image includes a second copy pattern of the first target pattern. The coordinates of the first copy pattern are different from the coordinates of the second copy pattern. Set a first off-axis displacement of the first replicated pattern and a second off-axis displacement of the second replicated pattern, such that the coordinates of the first replicated pattern after displacement are the same as the coordinates of the second replicated pattern after displacement; A computer-generated hologram algorithm is executed based on the first content image, the first off-axis displacement, the second content image, the second off-axis displacement, the wavelength of a light ray, and a first reconstruction distance to generate a phase image; and The liquid crystal silicon-coated panel is driven according to the phase image, and the liquid crystal silicon-coated panel receives the light and displays a first reconstructed image at the first reconstruction distance.

8. The projection method of claim 7, wherein the first off-axis displacement is in a first direction, and the projection method further includes: The intensity of the first replicated pattern is gradually increased along the first direction.

9. The projection method of claim 8, wherein the second off-axis displacement is in a second direction, and the projection method further includes: The intensity of the second replicated pattern is gradually increased along the second direction.

10. The projection method of claim 8, wherein the target pattern is located at a first coordinate, the first coordinate being located within the range corresponding to the liquid crystal silicon-coated panel, and the projection method further includes: The first off-axis displacement is set such that the coordinates of the first replicated pattern after displacement are different from the first coordinates and are outside the range corresponding to the liquid crystal silicon-coated panel.

11. The projection method of claim 7, wherein the liquid crystal silicon-coated panel comprises a plurality of pixels, and the projection method further comprises: The upper limit of the first off-axis displacement is determined based on the first reconstruction distance, the wavelength, and the size of the pixels.

12. The projection method of claim 7, wherein the target image further comprises a second target pattern, and the projection method further comprises: A third content image and a fourth content image are generated based on the target image, wherein the third content image includes a third copy of the second target image, and the fourth content image includes a fourth copy of the second target image, and the coordinates of the third copy are different from the coordinates of the fourth copy. Set the third off-axis displacement of the third replicated pattern and the fourth off-axis displacement of the fourth replicated pattern, such that the coordinates of the third replicated pattern after displacement are the same as the coordinates of the fourth replicated pattern after displacement. as well as The computer-generated hologram algorithm is executed according to a second reconstruction distance, so that the liquid crystal silicon-coated panel displays a second reconstructed image at the second reconstruction distance.

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