Multilayered fluorescent screens for scanning beam display systems

Abstract

Fluorescent screens and display systems and devices based on such screens using at least one excitation optical beam to excite one or more fluorescent materials on a screen which emit light to form images. The fluorescent materials may include phosphor materials and non-phosphor materials such as quantum dots.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example scanning laser display system having a fluorescent screen made of laser-excitable fluorescent materials (e.g., phosphors) emitting colored lights under excitation of a scanning laser beam that carries the image information to be displayed.

FIGS. 2A and 2B show one example screen structure and the structure of color pixels on the screen in FIG. 1.

FIG. 3 shows an example implementation of the laser module in FIG. 1 having multiple lasers that direct multiple laser beams on the screen.

FIG. 4 illustrates an example screen having a fluorescent stripe layer with fluorescent stripes for emitting red, green and blue colors under optical excitation of the scanning excitation light.

FIG. 5 shows an example fluorescent layer with fluorescent stripes formed on a supporting substrate.

FIG. 6 shows an example of a fluorescent screen with two dichroic layers.

FIGS. 7A and 7B illustrate two screen examples based on the screen design in FIG. 6.

FIG. 8 shows a fluorescent screen design with a contrast enhancement layer.

FIG. 9 shows a fluorescent screen design with a contrast enhancement material composition in each fluorescent stripe.

FIG. 10 illustrates an example of a fluorescent screen design that has a contiguous and uniform layer of mixed phosphors that emits white light.

FIGS. 11 and 12 show a fluorescent screen design with a Fresnel lens layer to direct scanning input excitation light to the fluorescent screen.

FIG. 13 shows a prismatic layer as an entrance layer for scanning excitation light in a fluorescent screen.

FIG. 13A illustrates an operation of the prismatic layer in FIG. 13.

FIG. 14 shows a high-index layer as an entrance layer for scanning excitation light in a fluorescent screen.

FIGS. 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 and 25 show various screen designs.

FIG. 26 shows an implementation of a low-index dielectric layer such as an air gap on the viewer side of the fluorescent layer in a fluorescent screen to improve the image quality of the fluorescent screen.

Claims

1. A display screen, comprising: a plurality of parallel screen layers which are engaged to form a planar stack and comprise:a fluorescent layer absorbing excitation light at an excitation wavelength to emit visible light at a different visible wavelength; anda prismatic layer comprising a plurality of prism elements which receive and couple the excitation light to the fluorescent layer.

2. The display screen as in claim 1, further comprising: a low-index layer formed on a side of and in contact with the fluorescent screen that is opposite to the prismatic layer and having a refractive index less than a refractive index of the fluorescent layer; anda screen layer in contact with the low-index layer and having a refractive index higher than the refractive index of the low-index layer.

3. The display screen as in claim 2, wherein: the low-index layer is an air gap.

4. The display screen as in claim 1, wherein: the fluorescent layer comprises a plurality of parallel fluorescent stripes; andwherein the display screen further comprises a plurality of parallel stripe dividers each located between two adjacent fluorescent stripes.

5. The display screen as in claim 4, wherein: the stripe dividers comprise a white paint that is optically reflective and opaque.

6. The display screen as in claim 5, wherein: the white paint comprises a mixture of a resin with either TiO2 or Barium Sulfate.

7. The display screen as in claim 4, wherein: each stripe divider comprises a fluorescent material that emits fluorescent light at a wavelength different from the excitation light and the visible light.

8. The display screen as in claim 4, wherein: each stripe divider comprises a reflective metal coating.

9. The display screen as in claim 4, wherein: at least three adjacent fluorescent stripes of the plurality of the fluorescent stripes are made of, respectively, a first fluorescent material to absorb the excitation light to emit first visible light of a first color, a second fluorescent material to absorb the excitation light to emit second visible light of a second color, and a third fluorescent material to absorb the excitation light to emit third visible light of a third color.

10. The display screen as in claim 4, wherein: each fluorescent stripe comprises a fluorescent material that absorbs the excitation light and emits white light; andwherein the screen layers further comprise a filter layer comprising a plurality of parallel filter stripes each aligned to a corresponding fluorescent stripe along a direction perpendicular to the to the screen layers, and wherein the fluorescent layer is located between the prismatic layer and the filter layer, andwherein at least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors.

11. The display screen as in claim 4, wherein: the screen layers further comprise a filter layer comprising a plurality of parallel filter stripes each aligned to a corresponding fluorescent stripe along a direction perpendicular to the screen substrate, the fluorescent layer located between the prismatic layer and the filter layer, andat least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors.

12. The display screen as in claim 11, wherein: the screen layers further comprise a plurality of second parallel stripe dividers each located between two adjacent filter stripes.

13. The display screen as in claim 12, wherein: the screen layers further comprise a dielectric layer between the fluorescent layer and the filter layer, andthe stripe dividers are in contact with the dielectric layer to separate the dielectric layer and the filter layer from each other by a gap.

14. The display screen as in claim 13, wherein: the gap between the filter layer and the dielectric layer is filled with a low-index dielectric material having a refractive index less than a refractive index of the dielectric layer.

15. The display screen as in claim 13, wherein: the gap between the filter layer and the dielectric layer is filled with air.

16. The display screen as in claim 4, wherein: the screen layers further comprise a filter layer comprising a plurality of parallel filter stripes each formed between two adjacent stripe dividers to align with a corresponding fluorescent stripe between the two adjacent stripe dividers, the fluorescent layer located between the prismatic layer and the filter layer,at least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors.

17. The display screen as in claim 16, wherein: the screen layers further comprise a dielectric layer between the prismatic layer and each fluorescent stripe and the dielectric layer has a refractive index less than a refractive index of the fluorescent stripe.

18. The display screen as in claim 16, wherein: the screen layers further comprise a dielectric layer between each filter stripe and a corresponding fluorescent stripe.

19. The display screen as in claim 1, wherein: the fluorescent layer comprises a uniform layer of a fluorescent material that absorbs the excitation light and emits white light;the screen layers further comprise a filter layer comprising a plurality of parallel filter stripes, the fluorescent layer being located between the prismatic layer and the filter layer; andat least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors.

20. The display screen as in claim 1, wherein: the screen layers further comprise a filter layer formed on one side of the fluorescent layer that is opposite to a side where the prismatic layer is located,the filter layer blocks transmission of the excitation light and transmits the visible light with an attenuation that is uniform over a spectral range of the visible light.

21. The display screen as in claim 1, wherein: the screen layers further comprise:a selective blocking layer that transmits the visible light and blocks the excitation light, anda neutral density filter layer that attenuates the visible light with an attenuation uniform over a spectral range of the visible light; andthe selective blocking layer and the neutral density filter layer are located at a side of the fluorescent layer that is opposite to the side where the prismatic layer is located.

22. The display screen as in claim 1, wherein: the prismatic layer is a first layer that receives the excitation light and is spaced from an adjacent screen layer by an air gap.

23. The display screen as in claim 1, wherein: the prismatic layer comprises a plurality of parallel prismatic stripes, andthe fluorescent layer comprises a plurality of parallel fluorescent stripes that are perpendicular to parallel prismatic stripes.

24. The display screen as in claim 1, further comprising: a Fresnel lens layer placed on one side of the prismatic layer that is opposite to the side where the fluorescent layer is located, the Fresnel lens layer directing the excitation light to the prismatic layer.

25. A display screen, comprising: a plurality of screen layers which are engaged to form a planar stack and comprise:a fluorescent layer comprising a plurality of parallel fluorescent stripes and absorbing excitation light at an excitation wavelength to emit visible light at a different and visible wavelength,a plurality of parallel stripe dividers each located between two adjacent fluorescent stripes, each strip divider having side walls that are reflective and opaque to the emitted visible light to optically isolate two adjacent fluorescent stripes, anda dielectric layer in contact with the stripe dividers and spaced from the fluorescent layer to define a gap between the dielectric layer and each fluorescent stripe.

26. The display screen as in claim 25, wherein: the gap is filled with air.

27. The display screen as in claim 25, wherein: the screen layers further comprise:an entrance layer to receive the excitation light and located on one side of the fluorescent screen that is opposite to the dielectric layer, anda filter layer on one side of the fluorescent layer where the dielectric layer is located, andthe filter layer blocks transmission of the excitation light and transmits the visible light with an attenuation uniform over a spectral range of the visible light.

28. The display screen as in claim 25, wherein: the screen layers further comprise:an entrance layer to receive the excitation light and located on one side of the fluorescent screen that is opposite to the dielectric layer,a selective blocking layer that transmits the visible light and blocks the excitation light, anda neutral density filter layer that attenuates the visible light with an attenuation uniform over a spectral range of the visible light; andthe selective blocking layer and the neutral density filter layer are located at a side of the fluorescent layer that is opposite to the side where the entrance layer is located.

29. The display screen as in claim 25, wherein: the screen layers further comprise:a filter layer comprising a plurality of parallel filter stripes each aligned to a respective fluorescent stripe along a direction perpendicular to the screen layers, each filter stripe of the filter layer being located between the gap and a respective fluorescent stripe, andat least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors.

30. The display screen as in claim 29, wherein: each filter stripe is formed between two adjacent stripe dividers and thus aligns with a corresponding fluorescent stripe between the two adjacent stripe dividers.

31. The display screen as in claim 30, wherein: the stripe dividers comprise a white paint that is optically reflective and opaque.

32. The display screen as in claim 31, wherein: the white paint comprises a mixture of TiO2 or barium sulfate and a resin.

33. The display screen as in claim 30, wherein: each stripe divider comprises a reflective metal coating.

34. The display screen as in claim 30, wherein: each stripe divider absorbs the excitation light and emits fluorescent light at a wavelength different from the excitation light and the visible light.

35. The display screen as in claim 25, further comprising: a Fresnel lens layer placed on one side of the dielectric layer that is opposite to the side where the fluorescent layer is located, the Fresnel lens layer directing the excitation light to the dielectric layer.

36. A display screen, comprising: a screen substrate;a fluorescent layer formed over the screen substrate and comprising a plurality of parallel fluorescent stripes, the fluorescent layer absorbing excitation light to emit visible light, wherein the excitation light and the visible light are at different wavelengths;a plurality of parallel stripe dividers each located between two adjacent fluorescent stripes;a dichroic layer formed over the screen substrate to receive the excitation light, wherein the dichroic layer transmits the excitation light and reflects the visible light.

37. The display screen as in claim 36, further comprising: a dielectric layer having a plurality of dielectric stripes each placed between the dichroic layer and the fluorescent layer and between two adjacent stripe dividers.

38. The display screen as in claim 36, further comprising: a filter layer formed over the screen substrate and comprising a plurality of parallel filter stripes each formed between two adjacent stripe dividers to align with a corresponding fluorescent stripe between the two adjacent stripe dividers, and wherein the fluorescent layer is located between the dichroic layer and the filter layer,wherein at least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors.

39. The display screen as in claim 38, further comprising: a dielectric layer having a plurality of dielectric stripes each placed between two adjacent stripe dividers and between the fluorescent layer and the filter layer.

40. The display screen as in claim 36, wherein: the stripe dividers comprise a white paint that is optically reflective.

41. The display screen as in claim 40, wherein: the white paint comprises a mixture of TiO2 or barium sulfate and a resin.

42. The display screen as in claim 36, wherein: each stripe divider comprises a reflective metal coating.

43. The display screen as in claim 36, wherein: each stripe divider comprises a fluorescent material that emits fluorescent light at a wavelength different from the excitation light and the visible light.

44. The display screen as in claim 36, further comprising: a second dichroic layer that transmits the visible light and reflects the excitation light, the second dichroic layer formed over the screen substrate, wherein the fluorescent layer is between the dichroic layer and the second dichroic layer.

45. The display screen as in 44; further comprising: a dielectric layer in contact with the second dichroic layer, wherein the second dichroic layer is between the fluorescent layer and the dielectric layer.

46. A display screen, comprising: a fluorescent layer comprising a plurality of parallel fluorescent stripes, the fluorescent layer absorbing excitation light to emit visible light, wherein the excitation light and the visible light are at different wavelengths;an entrance layer formed on a first side of the fluorescent layer to receive the excitation light and to direct the excitation light to the fluorescent layer; anda filter layer formed a second side of the fluorescent layer opposing the first side, the filter layer formed of a material that transmits the visible light with an attenuation uniform over a spectral range of the visible light.

47. The display screen as in claim 46, wherein: the filter layer further blocks transmission of the excitation light.

48. The display screen as in claim 46, further comprising: a second filter layer formed a second side of the fluorescent layer opposing the first side, the second filter layer blocking transmission of the excitation light and transmitting the visible light.

49. The display screen as in claim 46, wherein: the entrance layer comprises a prismatic layer which includes a plurality of prism elements.

50. The display screen as in claim 46, wherein: the entrance layer comprises a dielectric layer with a flat surface to receive the excitation light.

51. A display screen, comprising: a fluorescent layer that absorbs excitation light to emit visible light; anda first layer on a first side of the fluorescent layer operable to transmit the excitation light and to reflect the visible light, the first layer comprising a prismatic layer which comprises a plurality of prism elements.

52. The display screen as in claim 51, wherein: the fluorescent layer comprises parallel fluorescent stripes and stripe dividers between the fluorescent stripes.

53. The display screen as in claim 52, wherein: each stripe divider emits invisible fluorescent light under excitation by the excitation light.

54. A display screen, comprising: a fluorescent layer that absorbs excitation light to emit white light, andan array of color filters adjacent to the fluorescent layer to receive the emitted white light and to filter the white light to transmit colored light, each color filter transmitting a designated color and absorbing light of other colors, each designated color for one color filter being different from a designated color transmitted by a neighboring color filter.

55. The display screen as in claim 54, further comprising: a first layer on a first side of the fluorescent layer to transmit the excitation light to the fluorescent layer and to reflect the visible light.

56. The display screen as in claim 55, wherein: the first layer comprises a prismatic layer which comprises a plurality of prism elements.

57. A display screen, comprising: a plurality of screen layers which are engaged to form a planar stack and comprise:a fluorescent layer comprising a plurality of parallel fluorescent stripes and absorbing excitation light at an excitation wavelength to emit visible light at a different and visible wavelength,a plurality of parallel stripe dividers each located between two adjacent fluorescent stripes, each strip divider having side walls that are reflective and opaque to the emitted visible light to optically isolate two adjacent fluorescent stripes, anda dielectric layer in contact with the fluorescent stripes and the stripe dividers to couple the excitation light into the fluorescent stripes,a filter layer comprising a plurality of parallel filter stripes each aligned to a corresponding fluorescent stripe along a direction perpendicular to the screen layers, the fluorescent layer being located between the high-index dielectric layer and the filter layer, wherein at least three adjacent filter stripes are respectively made of a first filter material to transmit first visible light of a first color while absorbing light of other colors including a second color and a third color, a second filter material to transmit second visible light of the second color while absorbing light of other colors including the first and the third colors, and a third filter material to transmit third visible light of the third color while absorbing light of the other colors including the first and the second colors,a second dielectric layer between the fluorescent layer and the filter layer; anda plurality of second parallel stripe dividers each located between two adjacent filter stripes and in contact with the second dielectric layer.

58. The display screen as in claim 57, wherein: second parallel stripe dividers separate the transparent dielectric layer and the filter layer from each other by a gap.

59. The display screen as in claim 58, wherein: the gap between the filter layer and the transparent dielectric layer is filled with air.

60. The display screen as in claim 57, wherein: a facet of each second parallel stripe divider that faces away from the fluorescent layer is optically absorbent.

61. A display screen, comprising: a first dielectric layer that transmits excitation light at an excitation wavelength;a fluorescent layer comprising a plurality of parallel fluorescent stripes and absorbing the excitation light to emit visible light at a different and visible wavelength; anda second dielectric layer spaced from the fluorescent stripes by an air gap, wherein the second dielectric layer at least partially transmits the visible light, and wherein the fluorescent layer is positioned between the first and second dielectric layers.

62. The display screen as in claim 61, wherein: the second dielectric layer blocks the excitation light.

63. The display screen as in claim 61, wherein: the second dielectric layer uniformly attenuates light in a visible spectral range.

64. The display screen as in claim 61, wherein: the second dielectric layer blocks the excitation light and uniformly attenuates light in a visible spectral range.