CN106324855B

CN106324855B - Light source of projector and projector

Info

Publication number: CN106324855B
Application number: CN201610905870.2A
Authority: CN
Inventors: 刘卫东; 陈昱
Original assignee: Qingdao Hisense Electronics Co Ltd
Current assignee: Hisense Visual Technology Co Ltd
Priority date: 2010-11-24
Filing date: 2010-11-24
Publication date: 2019-08-16
Anticipated expiration: 2030-11-24
Also published as: CN103052911B; WO2012068725A1; CN106292149A; CN106324855A; CN103052911A

Abstract

The invention discloses a kind of light source of projector, projector and television sets.The light source of projector is using the synthesis light of laser and fluorescence as output light.By means of the invention it is possible to realize low speckle while realizing big colour gamut.

Description

Projector light source and projector

The present application is a divisional application of an invention patent application 201080068493.2 entitled "projector light source, projector, and television" filed on 24/11/2010.

Technical Field

The invention relates to the field of optics, in particular to a projector light source and a projector.

Background

Solid light sources such as lasers and LEDs are gradually replacing traditional gas light sources in various fields due to the characteristics of low energy consumption, small volume, long service life, green environmental protection and the like, and the application is more and more extensive. Laser and LED projection systems have become a focus of research and development in the field of projection display applications. Various laser and LED and fluorescent light source systems continue to emerge. Nevertheless, it is difficult to achieve laser display with outstanding color rendering capabilities beyond other display technologies while suppressing image noise due to laser speckle. Especially, the most critical green light source, such as laser, can realize the function of large color gamut, but the speckle noise of the image is serious. For example, the speckle noise can be eliminated by using the fluorescence excited by the short-wavelength laser as a light source, but the color function is limited.

Aiming at the problem that the speckle phenomenon is often serious when a large color gamut is realized in the related art, an effective solution is not provided at present.

Disclosure of Invention

The invention is provided for solving the problem that the speckle phenomenon is often serious when a large color gamut is realized in the related art, and therefore, the main purpose of the invention is to provide a projector light source, a projector and a television to solve the problem.

To achieve the above object, according to one aspect of the present invention, there is provided a projector light source. The projector light source uses the combined light of laser and fluorescence as output light.

In order to achieve the above object, according to another aspect of the present invention, there is provided a projector. The projector comprises the projector light source provided by the invention.

In order to achieve the above object, according to another aspect of the present invention, there is provided a television set. The television comprises the projector light source provided by the invention.

According to the invention, the synthetic light of laser and fluorescence is used as the light source of the optical projector, so that the problem that the speckle phenomenon is often serious when a large color gamut is realized in the related technology is solved, and the effect of realizing low speckle while realizing the large color gamut is achieved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1a is a schematic diagram of a projector light source according to a first embodiment of the invention;

FIG. 1b is a schematic diagram of a projector light source according to a second embodiment of the invention;

FIG. 1c is a schematic diagram comparing laser and fluorescence spectra;

FIG. 2a is a schematic illustration of a composed light according to a first embodiment of the invention;

FIG. 2b is a schematic illustration of a composed light according to a second embodiment of the invention;

FIG. 3a is a diagram of the effect of the color gamut produced by a composite light source according to an embodiment of the present invention;

FIG. 3b is a schematic diagram of the corresponding color gamut change and speckle contrast change when the laser fluorescence ratio changes, according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of an embodiment of the present invention using a blue laser as the excitation light;

FIG. 5a is a schematic diagram of a preferred embodiment of a projector light source according to the present invention;

FIG. 5b is a schematic diagram of another preferred embodiment of a projector light source according to the present invention;

FIG. 5c is a schematic diagram of another preferred embodiment of a projector light source according to the present invention;

FIG. 6 is a schematic diagram of a synthesis mechanism according to an embodiment of the invention; and

FIG. 7 is a schematic diagram of another synthesis mechanism according to an embodiment of the invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

FIG. 1a is a schematic diagram of a projector light source according to a first embodiment of the invention.

As shown in fig. 1a, the projector light source uses a combined light of laser light and fluorescent light as an output light.

In this embodiment, since laser light is used as the light source, a large color gamut can be realized, and since the combined light of laser light and fluorescent light is used as the output light, laser speckle reduction of an image while increasing the color gamut of a display system can be realized.

FIG. 1b is a schematic diagram of a projector light source according to a second embodiment of the invention; FIG. 1c is a schematic diagram comparing a laser spectrum and a fluorescence spectrum.

In this embodiment, the fluorescence is generated by excitation, as shown in fig. 1b, wherein the fluorescence can be generated by laser excitation or by LED light excitation. And synthesizing the laser and the fluorescence generated after excitation to obtain composite light.

First, the generation of the synthesized light is described by taking a green light source as an example. As shown in the figure, the green phosphor is excited by blue or ultraviolet laser to generate green fluorescence (green fluorescence refers to peak wavelength and most of the light is in green band), and the broadband green fluorescence is combined with the narrowband green laser to be used as the green light source of the projector, as shown in fig. 1 c.

Preferably, in the projector light source, any one or more of the blue light, the red light and the green light is synthesized by laser and fluorescence, for example, the green light can be synthesized by laser and fluorescence, the blue light or the red light can also be synthesized by laser and fluorescence, or the blue light, the red light and the green light can be synthesized by laser and fluorescence, and the projector light source in this form can realize a larger color gamut compared with the projector light synthesized by laser and fluorescence respectively by different colors (for example, the blue light is pure laser, and the green light is pure fluorescence).

FIG. 2a is a schematic illustration of a composed light according to a first embodiment of the invention; fig. 2b is a schematic view of a composed light according to a second embodiment of the invention.

The fluorescence and laser light can be combined by fiber coupler, waveguide coupler, as shown in fig. 2a, or by free space optics, and two light sources in close proximity can be projected onto the object simultaneously, as shown in fig. 2 b. That is, the light source 1 and the light source 2, for example, a laser light source and a fluorescent light source excited by the laser light source, are located on one side of the lens, and the lens combines the light projected from the light source 1 and the light source 2.

Preferably, the projector light source according to the embodiment of the present invention may include a laser light source, a fluorescent light source, and a combining mechanism for combining laser light generated by the laser light source and fluorescent light generated by the fluorescent light source.

The fluorescent light source may include a fluorescent powder mechanism and an excitation light source, wherein light emitted by the excitation light source generates fluorescence after passing through the fluorescent powder mechanism.

The fluorescent powder mechanism can comprise a color wheel and/or a superposition mechanism, wherein in the case that the fluorescent powder mechanism comprises the color wheel, different areas of the color wheel are coated with fluorescent powder with different colors; in the case where the phosphor mechanism includes a stacking mechanism, different layers of the stacking mechanism are coated with different colors of phosphors.

The excitation light source may be a laser light source or an LED light source.

The combining mechanism includes any one or more of a fiber coupler, a waveguide coupler, and a lens.

Fig. 3a is a diagram of the effect of the color gamut produced by a composite light source according to an embodiment of the invention.

The effect produced by the composite light source of fig. 1a to 1c can be shown by the triangle of color gamut, as shown in fig. 3a, the triangle ABC represents the expressible color gamut of the three-color light source of red (laser) -green (fluorescent) -blue (laser), and the color gamut triangle has small area and less expressible color due to the wide wavelength band of the fluorescent powder and the green color coordinate B close to the center.

After the green laser component is added, the green color coordinate D is far away from the center, the area of the color gamut triangle ADC is larger, and the expressible color is greatly increased.

Blue light and red light can be generated in the above manner, i.e., the blue light and the red light are synthesized using a laser and a fluorescent light. Because the influence degree of each color light on the size of the gamut triangle and the speckles is different, the green light source is synthesized by the method, the effect is most obvious, and the speckles can be inhibited while the gamut area is increased.

The above-described approach of combining laser light and fluorescence light provides a means to optimize the color saturation of the light source.

As shown in AEC in fig. 3a, this case is the case of full laser light, and it can be seen from the figure that, although the maximum color gamut can be obtained by full laser light, in this case too, the case of severe speckle occurs. That is, if the pure laser is used as the light source, the green color coordinate is at the boundary of the whole color gamut, and the triangular area of the color gamut is larger, but the pure laser light source brings serious laser coherent speckle, which affects the image quality.

It can be seen from the above various situations that the case where the color gamut triangle is ADC is the optimal way to synthesize fluorescence and laser in the present invention, and in this case, a relatively large color gamut can be obtained, and speckle can be greatly reduced.

FIG. 3a is now described in further detail. To describe the gamut size, we have to obtain the color stimulus values of the light source, such as:

where I (λ) is the light source spectral distribution.Is a standard stimulation curve. In xy color space, the color coordinates are:

z＝1-x-y

according to the xy coordinates of the red, green and blue light sources, the area size of the color gamut triangle can be calculated.

In order to quantitatively describe the speckle, uniform light intensity is irradiated on the screen, the light intensity reflected or projected by the screen generates non-uniformity (namely the speckle) due to the coherence of laser, the picture light intensity distribution is p (I) (p is the probability of the intensity I), and then the contrast of the speckle is defined as:

wherein,is the mean value of light intensity, σ_IIs the standard deviation. Both of these can be calculated from p (I). With strict calculation of the actual projection system screenp (i), the theory is very complex. The discussion now focuses on light sources. For the commonly used solid laser, the spectrum is very narrow and can be approximated to be completely correlated light, and the probability distribution of the speckle light intensity is a negative exponential function:

for a fluorescent light source, the spectrum is very wide and can be approximated to completely uncorrelated light, and the probability distribution of the speckle light intensity is a delta function:

p₂(I)＝δ(I)

according to the distribution functions p1 and p2 and the mixing proportion of the laser light source and the fluorescent light source, the light intensity distribution function of the synthetic light source can be obtained, and then the speckle contrast is obtained.

Fig. 3b is a calculation result of the example of fig. 3 a. Here, blue light is used as the laser LD, red light is used as the LED, and the color coordinates of the blue light and the red light are (0.1813, 0.0818), (0.6190, 0.3521), respectively. The green light is a mixture of solid laser light and fluorescence. The central wavelength of the solid laser is 532nm, and the bandwidth is 0.1 nm. The fluorescence center wavelength is 532nm, and the bandwidth is 80 nm.

Fig. 3b is a graph showing the change in color gamut and the change in speckle contrast when the green laser fluorescence ratio is changed. In the figure, curve A represents speckle contrast, and we can observe that when the fluorescence component is increased from 0 to about 60%, the speckle contrast is reduced, the contrast is not obviously reduced at 60-90%, and the contrast is continuously reduced after 90%. Such a variation behavior is caused by the synthesis of the negative exponential distribution and the δ distribution. Curve B is the relative area of the gamut triangle (i.e., the ratio of the gamut triangle area to the gamut triangle area when pure green phosphor is used), and we can see that as the phosphor composition increases, the gamut decreases.

For the purposes of reducing speckle contrast and increasing the design of the color gamut, about 60% fluorescence contribution is most effective. At the moment, the speckle contrast is reduced to 27% from 100% of a pure laser light source, and meanwhile, the xy space color gamut area is increased by 32% compared with a pure fluorescent light source. It is noted that for reasons of computational simplicity, the gamut area is performed in the xy gamut space, and the actual gamut surface increase is higher since the non-uniformity of the xy space underestimates the gamut increase. The color gamut of the fluorescent light source is too small, the color saturation is low, the fluorescent light source is only suitable for certain commercial projection applications, and the increased color gamut can meet the requirements of entertainment applications such as home theaters and the like through the mixing of laser and fluorescence. In addition, speckle contrast is approximately as small as 5% imperceptible to the human eye. Assuming in this example that the light source is completely coherent, in practical systems due to the use of laser arrays, various random devices and processes in the system, even if fluorescence is not mixed, the laser is not completely coherent, the speckle contrast is not 100%, and can be as small as 15-20% depending on the optical system. By mixing the laser light and the fluorescence light, the speckle contrast can be reduced to 5%.

Fig. 4 is a schematic wavelength diagram of a blue laser as an excitation light according to an embodiment of the present invention.

When blue laser is used as the excitation light, the fluorescence excitation can be designed to convert only part of the blue light into green light. So that the remaining blue light can be used as a blue light source.

In the projector light source, preferably, the laser light and the fluorescence light are synthesized in one of the following ways: synthesizing red laser, green laser and first fluorescence, wherein the first fluorescence is generated by exciting red phosphor and green phosphor with blue excitation light; or, the light emitted by the red light LED, the green laser and the second fluorescent light are synthesized, wherein the second fluorescent light is generated by exciting the green phosphor with the blue excitation light. That is, in the projector light source described above, the laser light may include a red laser light and a green laser light, and the fluorescence is a first fluorescence generated by exciting the red phosphor and the green phosphor with the blue laser light, or the projector light source may further include light emitted by a red LED, and the laser light includes a green laser light, and the fluorescence is a second fluorescence generated by exciting the green phosphor with the blue laser light.

Fig. 5a is a schematic diagram of a preferred embodiment of a projector light source according to the present invention.

As shown in fig. 5a, the blue laser is used to excite the red phosphor and the green phosphor, and then the red laser and the green laser are mixed, and the remaining blue light can be used as the blue light source, so that the red, green and blue light source with optimized color saturation can be manufactured, and the effects of large color gamut and low speckle can be achieved.

Fig. 5b is a schematic diagram of another preferred embodiment of a projector light source according to the present invention.

In practical applications, the red light source can be replaced by an LED according to different applications, and the excitation light can also be an LED light source as shown in fig. 5 b. For example, taking a red LED as an example, light generated by exciting green phosphor is synthesized by light generated by the red LED, green laser light, and blue excitation light, and the synthesized composite light is used as a light source.

Fig. 5c is a schematic diagram of another preferred embodiment of a projector light source according to the present invention.

As shown in fig. 5c, in this embodiment, ultraviolet light is used as the excitation light, and when the phosphor is excited by ultraviolet light, the phosphor can generate green fluorescence, red fluorescence, or blue fluorescence, so that in this case, the selection of the laser light source can be more flexible, and it should be noted that the ultraviolet light source used as the excitation light source can be either a laser light source or an LED light source, and meanwhile, the light source 1 and the light source 2 in the figure can both be laser light sources, one can be a laser light source, and the other can be an LED light source.

As shown in the figure, after the ultraviolet light is used as the excitation light to generate the fluorescence, the fluorescence may be combined with the laser light generated by the laser light source, or the fluorescence may be combined with the laser light generated by the laser light source and the light generated by the LED light source.

In summary, when ultraviolet light is used as the excitation light, the ultraviolet light is used as the excitation light to generate fluorescence of any one of green light, blue light and red light, so that the selection of the laser light source for generating laser light and the excitation light source for generating fluorescence can be more flexible.

FIG. 6 is a schematic diagram of a synthesis mechanism according to an embodiment of the invention; and FIG. 7 is a schematic diagram of a compositing mechanism according to an embodiment of the invention.

Fig. 6 and 7 show different ways of generating fluorescence. Fig. 6 is a color wheel, and phosphors of different colors are coated on different areas of the color wheel. Fig. 7 is a method of overlapping phosphor layers, and different color phosphors are coated on the same place layer by layer. In fig. 6, a of fig. 6 corresponds to the case where ultraviolet light is used as the excitation light source, and then red, green, and blue fluorescence can be generated; the graph b in fig. 6 corresponds to the case of blue light as the excitation light source (corresponding to the case of fig. 5 a), in which red and green fluorescence can be generated, the blue light will pass through the transparent color wheel portion, and the blue light as the excitation light source can be partially projected to be directly used as the blue light source; the graph c in fig. 6 corresponds to the situation of fig. 5c, when red light is generated by the LED, only green fluorescence needs to be generated.

The fluorescence is generated in a reflection mode or a projection mode.

The embodiment of the invention also provides a projector which is provided with the projector light source in any one of the embodiments.

Specifically, the projector may include a projector light source, a micro display, wherein the projector light source is configured to output a synthesized light; and the micro display is used for modulating the synthesized light output by the light source of the projector.

In this embodiment, since a polarized light source is used, and the polarized light is modulated by the 3D signal through the microdisplay, and the modulated polarized light is projected, stereoscopic projection can be realized.

The projector according to the embodiment of the invention can be classified into a front projection type and a rear projection type, wherein a screen of the front projection type is a reflection type, and a screen of the rear projection type is a projection type.

The embodiment of the invention also provides a television, which is provided with the projector light source in any one of the above embodiments.

The television set acts as a display device, the signal sources of which are mainly from the antenna and the cable television channel. And the projector is used as a display device, and the signal source is mainly from DVD, Blu-Ray, computer, and the like. However, due to the advent of set-top boxes, televisions can also play film sources from DVDs, Blu-Ray, etc., and projectors can also play film sources from television channels.

The projector according to the embodiment of the invention can be divided into a front projection mode and a rear projection mode, for the rear projection projector, a screen and the projector are integrated, and a set top box is arranged in the projector, so that a television signal can be received and processed, and the projector can be used as the television according to the embodiment of the invention. For front projection projectors, the screen is separate from the projector and typically does not contain a set-top box. The front projection polarization-maintaining screen is of a reflective type, and the rear projection polarization-maintaining screen is of a projection type.

From the above description, it can be seen that the present invention achieves the following technical effects:

the invention considers the synthetic application of laser, fluorescence and LED in projection display, thereby realizing the display effect of large color gamut and low speckle;

the invention integrates the advantages of laser and fluorescence, provides a laser and fluorescence excited by the laser to be used as a light source at the same time, and realizes the laser projection display effect with large color gamut and low speckle;

by utilizing the combined light of the laser and the laser-generated fluorescence as the projector light source, a new large color gamut and low speckle laser display scheme is provided. The scheme can realize the advantage of rich laser display colors, and overcome the laser speckle of the maximum performance defect of laser display.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The projector light source is characterized by comprising a laser light source, wherein the laser light source comprises a blue laser, a red laser and a green laser;

the fluorescent light source comprises a fluorescent powder mechanism and an excitation light source, the fluorescent powder mechanism is coated with red fluorescent powder and green fluorescent powder, and light emitted by the excitation light source generates red fluorescent light and green fluorescent light after passing through the fluorescent powder mechanism;

and the synthesizing mechanism is used for synthesizing the laser generated by the laser light source and the fluorescence generated by the fluorescence light source.

2. The projector light source as claimed in claim 1, wherein the phosphor mechanism is a color wheel, and different areas of the color wheel are coated with different color phosphors, the phosphors including red phosphor and green phosphor.

3. The projector light source as claimed in claim 2 wherein the excitation light source is a blue laser, the color wheel further comprising a transparent portion, a portion of the blue laser being projected through the transparent portion of the color wheel to serve as the blue light source.

4. The projector light source as defined in claim 2 wherein the phosphor further comprises a blue phosphor and the excitation light source is an ultraviolet light source.

5. The projector light source as in claim 1, wherein the phosphor mechanism is a superimposing mechanism, wherein different layers of the superimposing mechanism are coated with different color phosphors, the phosphors comprising red phosphors and green phosphors.

6. The projector light source as defined in claim 5 wherein the phosphor further comprises a blue phosphor and the excitation light source is an ultraviolet light source.

7. The projector light source as claimed in claim 1 wherein the red fluorescent component is 60% of the red laser light and the red fluorescent light; and/or the presence of a gas in the gas,

the green fluorescence component accounts for 60% of the green laser light and the green fluorescence.

8. The projector light source as claimed in claim 4 or 6 wherein the blue phosphor component is 60% of the blue laser and the blue phosphor.

9. The projector light source as claimed in claim 1 wherein the combining mechanism comprises one or any plurality of: fiber couplers, waveguide couplers, and lenses.

10. The projector light source as defined in claim 1 wherein the fluorescent light is generated in a reflective or a projective manner.

11. A projector having the projector light source claimed in any one of claims 1 to 10.