A single-fluorescent wheel architecture color enhancement method

Abstract

This invention discloses a color enhancement method for a single phosphor wheel architecture, comprising a projector using a single phosphor wheel. This projector does not have a color wheel; yellow (Y), red (R), and green (G) are all generated from the phosphor wheel and produced by laser irradiation of phosphors. Blue (B) is generated from the optical path behind the phosphor wheel by creating a hole in the phosphor wheel. The laser irradiation occurs in the optical path system where a blue laser excites the phosphor. The red (R) phosphor produced after irradiation has a poor effect, with a color bias towards orange. Without changing the single phosphor wheel architecture, the color coordinates of red (R) are improved by adding a glass filter to the surface of the red (R) phosphor. To improve the color of a single phosphor wheel, this invention requires adding a filter to the area where color improvement is needed. However, the added filter's refractive index and thickness cause the original focal point to shift backward. This is compensated for by locally processing an aluminum sheet to correct the shift in focal point, allowing each color to achieve its optimal color coordinates and efficiency.

Description

Technical Field

[0001] This invention relates to the field of projector projection color technology, and specifically to a color enhancement method for a single phosphor wheel architecture. Background Technology

[0002] Currently, blue lasers are widely used to excite phosphor projection, but there are still some core technical issues: the selection of the color wheel determines the coordinates of the pure color and the efficiency; the accuracy of the synchronization between the phosphor wheel and the color wheel affects the smoothness of grayscale and the vividness of each pure color; and adding glass to the color wheel leads to poor efficiency.

[0003] In traditional DLP laser projectors, the R and G colors are generated primarily by laser light hitting a phosphor wheel to excite YG or pure Y light. This light is then filtered out by a filter on the color wheel to produce the RG color. While this method can effectively generate the three primary colors, the use of two motors requires significant effort to achieve accurate synchronization. This also increases costs by requiring additional motors and sensors for synchronization. Furthermore, the increased absorption and transmittance of the glass material on the color wheel leads to reduced brightness.

[0004] Currently, the most common projectors use a single phosphor wheel. Because they do not use a color wheel, all three primary colors need to be generated from the phosphor wheel. Yellow (Y), red (R), and green (G) are generated by laser irradiation of phosphor, while blue (B) is generated by punching holes in the phosphor wheel and producing light from the back of the phosphor wheel.

[0005] This method also has certain drawbacks: using a single-wheel fluorescent wheel (such as...) Figure 2 In projectors without a color wheel filter, all three primary colors are generated from a phosphor wheel. The phosphors for G (green) and Y (yellow) have relatively low sensitivity, so using lasers of different wattages for excitation will not result in significant differences in Gx and Gy (e.g.,...). Figure 3 However, the red powder on the fluorescent wheel is highly sensitive to temperature compared to other colors. The limited selection of red powder results in a red color that is more orange. Consequently, if the user projects a red-related image, the output image will differ significantly from the original image, causing image distortion. Summary of the Invention

[0006] To address the aforementioned technical deficiencies, the objective of this invention is to provide a color enhancement method using a single phosphor wheel architecture.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a color enhancement method with a single phosphor wheel architecture, including a projector using a single phosphor wheel. The projector does not have a color wheel. Yellow (Y), red (R), and green (G) are all generated from the phosphor wheel and are all generated by laser irradiation of phosphor. Blue (B) is generated from the light path behind the phosphor wheel by punching holes in the phosphor wheel.

[0008] The aforementioned laser irradiation occurred in the optical path system where a blue laser excites phosphors. The red R phosphor produced a poor effect after irradiation, with a color bias towards orange. Without changing the single phosphor wheel architecture, the color coordinates of the red R phosphor were improved by adding a glass filter to the surface of the red R phosphor. After adding the glass filter, the laser irradiation area increased, resulting in a larger light spot on the phosphor wheel, indicating that the intersection of the light spots also extended backward. As a result, the phosphor wheel was at its optimal color coordinates and brightness on the white W, green G, and yellow Y images. However, the red R image experienced a shift in brightness and color coordinates due to the backward extension of the focal point. To ensure optimal color and brightness for each color without changing the original optical architecture, the backward extension distance D of the focal point was calculated using Snell's Law (n1sinθ1 = n2sinθ2) and trigonometric functions based on the glass thickness. The backward extension distance D of the focal point was compensated by changing the thickness of a local area of ​​the phosphor wheel.

[0009] Furthermore, the thickness of a local area of ​​the phosphor wheel is altered to compensate for the backward extension distance D of the focal point. Specifically, some processing is done on a local area of ​​the phosphor wheel. In the red R area, processing is done to sink a local area of ​​the phosphor wheel, forming a concave platform. The reduction in thickness in this area is related to the increase in glass thickness and refractive index. The thicker the glass, the greater the backward displacement of the focal point. After applying phosphor coating and attaching a filter at this concave platform, the thickness of the attached filter is made to be close to that of the phosphors of other colors. This can compensate for the backward extension distance of the focal point due to the thickness and refractive index of the glass, thereby achieving the optimal brightness of each color on the same plane.

[0010] The beneficial effects of this invention are as follows: If the color of a single phosphor wheel is to be improved, a filter needs to be added to the area where the color is to be improved. However, because the refractive index and thickness of the filter are increased, the original focal point is moved backward. The distance of the focal point shift is compensated by locally processed aluminum sheet, so that each color can achieve the best color coordinates and efficiency. In addition, the red phosphor can increase Rx due to the addition of the filter, thereby increasing the proportion of REC709. In terms of cost, the lack of a color wheel can significantly reduce the cost. In terms of efficiency, since other G and Y colors do not use filters, there is no material absorption of glass and coating transmittance loss, thus reducing the loss of brightness. Attached Figure Description

[0011] The structure and features of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0012] Figure 1 This is a schematic diagram illustrating the generation of yellow (Y), red (R), and green (G) using a fluorescent wheel based on existing technology.

[0013] Figure 2 This is a schematic diagram illustrating the addition of a filter to the red area of ​​the fluorescent wheel as described in this invention.

[0014] Figure 3 This is a schematic diagram of how a recessed platform is machined at the red screen of the fluorescent wheel in this invention to correct the thickness of the filter and the backward extension distance of the focal point.

[0015] Figure 4 This is a schematic diagram showing that, in this invention, after applying a coating of phosphor and attaching a filter to the recessed area, the phosphor is highly similar to other colors.

[0016] Appendix Figure 1-4 In the diagram, 1. Phosphor wheel, 2. Green (G), 3. Red (R), 4. Yellow (Y), 5. Filter, 6. Recess, 7. Thickness of a local area of ​​the processed phosphor wheel, 8. Thickness of red phosphor, 9. Thickness of green phosphor, 10. Thickness of a local area of ​​the unprocessed phosphor wheel. Detailed Implementation

[0017] See appendix Figure 1-4 This is one embodiment of the present invention, disclosing a color enhancement method using a single phosphor wheel architecture. The method includes a projector using a single phosphor wheel, which does not have a color wheel. Yellow (Y4), red (R3), and green (G2) are all generated from phosphor wheel 1, and are all generated by laser irradiation of phosphor. Blue (B) is generated from the optical path behind the phosphor wheel by creating a hole in the phosphor wheel. (See attached image.) Figure 1 As shown in the image.

[0018] The aforementioned laser irradiation occurred in the optical path system where a blue laser excites the phosphor. The resulting red R3 phosphor produced a poor effect, with a color bias towards orange. Without altering the single phosphor wheel architecture, the color coordinates of the red R3 phosphor were improved by adding a glass filter 5 to the surface of the red R3 phosphor. (See attached image). Figure 2As shown; however, after adding the glass filter 5, the laser irradiation area becomes larger, resulting in a larger light spot on the phosphor wheel 1, indicating that the intersection of the light spots also extends backward. As a result, the phosphor wheel is at the optimal color coordinates and color brightness on the white W, green G, and yellow Y screens. However, the red R screen experiences a shift in brightness and color coordinates due to the backward extension of the focal point. Without changing the original optical architecture, in order to ensure that each color has the optimal color and brightness, the backward extension distance D of the focal point is calculated according to Snell's Law n1sinθ1= n2sinθ2 and using the glass thickness combined with trigonometric functions. The backward extension distance D of the focal point is compensated by changing the thickness of the local area of ​​the phosphor wheel.

[0019] The backward extension distance D of the focal point is compensated by changing the thickness of a local area of ​​the fluorescent wheel. Specifically, some processing is done on a local area of ​​the fluorescent wheel, specifically in the red R area, to make a local area of ​​the fluorescent wheel sink, forming a concave platform 6. (See [reference]). Figure 3 As shown, the reduction in thickness in this area is related to the increase in glass thickness and refractive index. The thicker the glass filter, the greater the range of focal point displacement. After applying red phosphor at position 6 and attaching the filter, the thickness of the attached filter is made to be very close to that of phosphors of other colors. (See [reference]). Figure 4 As shown, the thickness of the local area of ​​the processed phosphor wheel, plus the thickness of the red phosphor 8 and the thickness of the filter 5, is very close to the thickness of the green phosphor 9 and the thickness of the local area of ​​the unprocessed phosphor wheel 10. This can compensate for the distance that the focal point of the glass extends backward due to the thickness of the glass and the refractive index, thereby achieving the optimal brightness of each color on the same plane.

Claims

1. A color enhancement method using a single phosphor wheel architecture, comprising a projector using a single phosphor wheel, wherein the projector does not have a color wheel, yellow (Y), red (R), and green (G) are all generated from the phosphor wheel and are generated by laser irradiation of phosphor, and blue (B) is generated from the optical path behind the phosphor wheel by punching holes in the phosphor wheel; the aforementioned laser irradiation occurs in the optical path system of the blue laser exciting the phosphor, and the red (R) phosphor produced after irradiation has a poor effect and the color is orange-toned, characterized in that: Without altering the single phosphor wheel architecture, the chromatic coordinates of red R phosphor are improved by adding a glass filter to the surface of the red R phosphor. Adding the glass filter increases the laser irradiation area, resulting in a larger light spot on the phosphor wheel, meaning the intersection of the light spots extends backward. Consequently, the phosphor wheel achieves optimal chromatic coordinates and brightness on the white W, green G, and yellow Y images. However, the red R image experiences a shift in brightness and chromatic coordinates due to the backward extension of the focal point. To ensure optimal color and brightness for each color without changing the original optical architecture, the backward extension distance D of the focal point is calculated using Snell's Law (n1sinθ1 = n2sinθ2) and trigonometric functions based on the glass thickness. The backward extension distance D is compensated by altering the thickness of a local area of ​​the phosphor wheel.

2. The color enhancement method for a single phosphor wheel architecture according to claim 1, characterized in that: The backward extension distance D of the focal point is compensated by changing the thickness of a local area of ​​the phosphor wheel. Specifically, some processing is done on a local area of ​​the phosphor wheel. Processing is done in the red R area to make a local area of ​​the phosphor wheel sink, forming a concave platform. The reduction in thickness of this area is related to the increase in glass thickness and refractive index. The thicker the glass, the greater the range of backward displacement of the focal point. After applying phosphor coating and attaching a filter at the concave platform, the thickness of the attached filter is made to be close to that of the phosphors of other colors. In this way, the backward extension distance of the focal point due to the thickness and refractive index of the glass can be compensated, thereby achieving the optimal brightness of each color on the same plane.

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