CN110398877B

CN110398877B - Projection system and adjusting method thereof

Info

Publication number: CN110398877B
Application number: CN201910228334.7A
Authority: CN
Inventors: 王博; 刘铠铭; 许明祐
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2018-04-25
Filing date: 2019-03-25
Publication date: 2021-11-02
Anticipated expiration: 2039-03-25
Also published as: CN110398877A

Abstract

The invention discloses a projection system and an adjusting method thereof. The first light source emits a first light. The second light source emits second light. The wavelength conversion element converts part or all of the second light into third light, and the third light comprises red light and green light. The wavelength range of the first light is within the wavelength range of the red light in the third light, and the wavelength range of the first light is greater than the peak wavelength of the red light in the third light. The first light splitting component enables the first light to penetrate or reflect. The second light splitting part removes red light in part of the third light. The second beam splitter has a critical transmission wavelength, and the critical transmission wavelength is within or outside the wavelength range of the first light to remove part of or not remove the first light respectively.

Description

Projection system and adjusting method thereof

Technical Field

The invention relates to a projection system and an adjusting method thereof.

Background

Generally, it is difficult to achieve the brightness, color saturation and white balance specified by the Digital Cinema standards (DCI) simultaneously in a projection system using a yellow fluorescent wheel. Since the yellow light converted by the yellow fluorescent wheel contains non-uniform proportions of red light and green light, additional components are required to reduce the red light or the green light if the color saturation and white balance specified by the digital video standard are to be achieved. However, this results in a reduction in the brightness of the projection system, and if the brightness is to meet the brightness standard specified by the digital video standard, the power of the entire light source is increased. However, the power of the light source cannot be increased without an upper limit, and the light source may be overheated, have a reduced lifetime, and have a reduced performance when operated at a high power.

Disclosure of Invention

One aspect of the present invention is a projection system.

According to an embodiment of the present invention, a projection system includes a first light source, a second light source, a wavelength conversion element, a first beam splitter, and a second beam splitter. The first light source emits a first light. The second light source emits second light. The wavelength conversion element converts part or all of the second light into third light, and the third light comprises red light and green light. The wavelength range of the first light is within the wavelength range of the red light in the third light, and the wavelength range of the first light is greater than the peak wavelength of the red light in the third light. The first light splitting component enables the first light to penetrate or reflect. The second light splitting part removes red light in part of the third light. The second beam splitter has a critical transmission wavelength, and the critical transmission wavelength is within or outside the wavelength range of the first light to remove part of or not remove the first light respectively.

In an embodiment of the invention, the peak wavelength of the second light is smaller than the peak wavelength of the third light, and the peak wavelength of the third light is smaller than the peak wavelength of the first light.

In an embodiment of the invention, the projection system further includes a light distribution device for dividing the second light into a first portion and a second portion, and the wavelength conversion element converts the first portion of the second light into a third light.

In an embodiment of the invention, the first light beam sequentially passes through the first light splitting element and the second light splitting element, the first portion of the second light beam sequentially passes through the second light splitting element, the wavelength conversion element and the second light splitting element, and the second portion of the second light beam sequentially passes through the first light splitting element and the second light splitting element.

In an embodiment of the invention, the first light splitter combines the first light and the second portion of the second light, and the second light splitter combines the first light that is not removed, the second portion of the second light, and the third light that is not removed into white light.

In an embodiment of the invention, the projection system further includes an integration rod, and the white light is incident into the integration rod.

In an embodiment of the invention, the projection system further includes a third light source emitting a fourth light.

In an embodiment of the invention, the first light beam sequentially passes through the first light splitting element and the second light splitting element, the second light beam sequentially passes through the second light splitting element, the wavelength conversion element and the second light splitting element, and the fourth light beam sequentially passes through the first light splitting element and the second light splitting element.

In an embodiment of the invention, the peak wavelength of the second light is smaller than the peak wavelength of the fourth light, the peak wavelength of the fourth light is smaller than the peak wavelength of the third light, and the peak wavelength of the third light is smaller than the peak wavelength of the first light.

In an embodiment of the invention, the first light splitter combines the first light and the fourth light, and the second light splitter combines the first light without being removed, the third light without being removed, and the fourth light into white light.

In an embodiment of the invention, the second beam splitter is a dichroic mirror having a semi-transmission wavelength, and the semi-transmission wavelength is between a peak wavelength of the first light and a peak wavelength of the third light.

In an embodiment of the invention, the wavelength range of the first light is 637nm to 642nm, and the semi-transmission wavelength of the second beam splitter is 629 nm.

In an embodiment of the invention, the first light has a wavelength ranging from 642nm to 646nm, and the second beam splitter has a semi-transmissive wavelength of 631 nm.

In an embodiment of the invention, the projection system further includes notch filters with semi-transmission wavelengths of 565nm and 586nm at two ends, respectively, and the minimum transmittance is less than 40%.

One aspect of the present invention is a method for adjusting a projection system.

In an embodiment of the present invention, a method for adjusting a projection system includes the following steps: (a) removing part of the first light and/or part of the third light by using a second light splitting element; (b) adjusting a first removal amount of the first light and a second removal amount of the third light; (c) adjusting the power of the first light source to make the color saturation and white balance of the projection system reach preset standards; and (d) repeating the steps (b) and (c) to find the lowest power of the first light source.

In one embodiment of the present invention, the step (a) further includes: defining a boundary value, removing the part of the first light ray with the wavelength less than the boundary value, and removing the part of the third light ray with the wavelength more than the boundary value.

In an embodiment of the invention, the boundary value is between a peak wavelength of the first light and a peak wavelength of the third light.

In one embodiment of the present invention, the step (b) further includes: the first removing amount of the first light and the second removing amount of the third light are adjusted by adjusting the boundary value.

In one embodiment of the present invention, the step (b) further includes: the first removal amount of the first light and the second removal amount of the third light are weighted by the tristimulus values, and the most appropriate boundary value is calculated.

In the above embodiment of the present invention, the projection system can reach the Digital television standard (DCI) at a lower power with the aid of the first light source, and effectively reduce the risk of thermal degradation of the light source due to an excessively high power. In addition, the second beam splitter is properly selected, so that the intensity ratio, white balance and color gamut of red, green and blue colors in the projection system can more easily reach the digital video standard. In addition, the invention also provides an adjusting method of the projection system, which considers the problem that human eyes recognize the tristimulus values of three primary colors besides the color intensity, and effectively improves the operating efficiency of the projection system. Finally, the projection system and the adjustment method thereof are compatible with the prior art, and the technical effect can be obtained without extra large cost.

Drawings

FIG. 1 is a top view of a projection system according to an embodiment of the invention.

FIG. 2 is a graph of intensity versus wavelength for the various light rays of the projection system of FIG. 1.

FIG. 3 is a graph of reflectance-wavelength dependence of a second beam splitter of the projection system of FIG. 1 and intensity-wavelength dependence of the band of red light in the third light and the band of first light.

FIG. 4 is a graph of transmittance versus wavelength for a notch filter of the projection system of FIG. 1.

FIG. 5 is a top view of a projection system according to another embodiment of the invention.

FIG. 6 is a top view of a projection system according to another embodiment of the invention.

FIG. 7 is a graph of intensity versus wavelength for the various light rays of the projection system of FIG. 6.

FIG. 8 is a flowchart illustrating an adjustment method of the projection system of FIG. 1.

Wherein, the reference number bit:

100. 100a, 100 b: projection system

110: first light source

120: second light source

130: third light source

140: wavelength conversion element

150: first light splitting member

160: second light splitting part

170: integration rod

180: optical path adjusting element

190: notch filter

200: light distribution device

210: adjustment method

S220, S230, S240, S250: step (ii) of

L1: the first light ray

L2: the second light ray

L2 a: the first part

L2 b: the second part

L3: the third light ray

L3 r: red light

L3 g: green light

L4: the fourth light ray

Detailed Description

In the following description, for purposes of explanation, numerous implementation details are set forth in order to provide a thorough understanding of the various embodiments of the present invention. It should be understood, however, that these implementation details are not to be interpreted as limiting the invention. That is, in some embodiments of the invention, such implementation details are not necessary. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings.

Fig. 1 is a top view of a projection system 100 according to an embodiment of the invention. The projection system 100 includes a first light source 110, a second light source 120, a third light source 130, a wavelength conversion element 140, a first beam splitter 150, a second beam splitter 160, a light integrator 170, and a light path adjusting element 180. The first light source 110 emits a first light L1, the second light source 120 emits a second light L2, and the third light source 130 emits a fourth light L4. The wavelength converting element 140 converts the second light L2 into third light L3. The first beam splitter 150 combines the first light L1 and the fourth light L4 into the second beam splitter 160, and the second beam splitter 160 then combines the first light L1, the third light L3 and the fourth light L4 into the integration rod 170. It should be noted that, the light splitting element combines the light beams to mean an integration on a light path, and the light beams may emit light alternately or simultaneously according to a time sequence.

As shown in fig. 1, the first light L1 emitted from the first light source 110 sequentially passes through the first light splitter 150 and the second light splitter 160. The second light L2 emitted from the second light source 120 passes through the optical path adjusting element 180, the second beam splitter 160, the wavelength conversion element 140 and the second beam splitter 160 in sequence. The fourth light L4 emitted from the third light source 130 passes through the first light splitter 150 and the second light splitter 160 in sequence. It should be understood that the optical path may be modified according to practical requirements. For example, optical path adjusting elements 180 may be disposed throughout the optical path of fig. 1 to change the traveling direction of the optical path and the positions where the elements are disposed. Specifically, the optical path adjusting element 180 may be a mirror.

As shown in fig. 1, the first light splitting element 150 and the second light splitting element 160 separate different wavelength bands of a light beam. In this embodiment, the first light splitter 150 and the second light splitter 160 reflect light of a specific wavelength band and allow light of other wavelength bands to pass through, thereby separating different wavelength bands in one light beam. Specifically, in the present embodiment, the first beam splitter 150 and the second beam splitter 160 are dichroic mirrors (dichroic), and the wavelength band of reflection and the wavelength band of transmission can be determined by setting the semi-transmission wavelength (T50%) of the dichroic mirrors. In other embodiments, the first light splitter 150 and the second light splitter 160 may be other elements, such as a dichroic prism (x cube) to separate different wavelength bands of light.

As shown in fig. 1, the first light beam L1 and the fourth light beam L4 are incident on two opposite surfaces of the first light splitter 150, respectively. The first light beam splitter 150 reflects the first light beam L1 and allows the fourth light beam L4 to pass through, such that the first light beam L1 and the fourth light beam L4 are combined into the same light beam on the same side of the first light beam splitter 150.

As shown in fig. 1, the light beam including the first light L1 and the fourth light L4 and the second light L2 are incident on the same side of the second beam splitter 160. The second beam splitter 160 allows the first light L1, the second light L2 and the fourth light L4 to pass through. The second light L2 passing through the second light splitter 160 enters the wavelength conversion element 140, and is converted into a third light L3 by the wavelength conversion element 140 and reflected to the other side of the second light splitter 160, at this time, the second light splitter 160 reflects the third light L3, so that the first light L1, the third light L3 and the fourth light L4 are combined into a same light beam.

As shown in fig. 1, the first light L1, the third light L3 and the fourth light L4 are incident into the integration rod 170 along a light path. It should be noted that optical elements may be added to the middle, front or rear light path of the integration rod 170 to perform detailed adjustment on the first light L1, the third light L3 and the fourth light L4 to optimize the performance of the projection system 100.

FIG. 2 is a graph of intensity versus wavelength for the various light rays of the projection system 100 of FIG. 1. The peak wavelengths of the light beams are sequentially the second light beam L2, the fourth light beam L4, the third light beam L3 and the first light beam L1 from small to large.

As shown in fig. 2, in the present embodiment, the first light source 110 is a red laser, and the first light L1 has a wavelength range of about 637nm to about 646nm and a peak wavelength of about 638 nm. The second light source 120 is a blue laser, and emits a second light beam L2 with a peak wavelength of about 455 nm. The third light source 130 is a blue laser, and emits a fourth light L4 with a peak wavelength of about 462 nm. In the present embodiment, the wavelength conversion element 140 (shown in fig. 1) is a yellow phosphor wheel (yellow phosphor wheel), and the peak wavelength of the third light L3 converted by the wavelength conversion element 140 of the second light L2 is between about 500nm and 700 nm.

In some embodiments, the waveform, the wavelength range and the peak wavelength of the second light L2 emitted by the second light source 120 can be adjusted according to the characteristics of the wavelength conversion element 140 to achieve a better conversion effect, so as to increase the intensity of the converted third light L3. Taking this embodiment as an example, the wavelength range and the peak wavelength of the second light L2 emitted by the second light source 120 can be adjusted according to the characteristic that the phosphor on the yellow phosphor wheel has different conversion rates for the light with different wavelength bands.

As shown in FIG. 2, the third light L3 can be further divided into a green light L3g with a peak wavelength between about 500nm and 600nm, and a red light L3r with a peak wavelength between about 600nm and 700 nm.

As shown in fig. 1 and 2, since the third light L3 includes green and red wavelength bands and the fourth light L4 includes blue wavelength bands, the light combined by the third light L3 and the fourth light L4 into the integration rod 170 can be used as the original color light (i.e., white light) of the projection system 100. As shown in fig. 2, in some cases, the intensity of the red light L3r in the third light L3 is lower than that of the green light L3g, and the intensity of the whole red band can be adjusted by the first light L1 incident into the integration rod 170.

As shown in fig. 1 and fig. 2, by adjusting the intensity and the peak wavelength of the first light L1 emitted by the first light source 110, the color saturation, the white balance, and the brightness of the original color light of the projection system 100 can easily reach the Digital Cinema standards (DCI). In addition, the first light source 110 shares the higher power originally provided by the second light source 120 for driving the wavelength conversion element 140, so that the second light source 120 can operate under the condition of outputting lower power, thereby reducing the risk of thermal decay (thermal decay) of the wavelength conversion element 140 under high-energy conversion.

FIG. 3 is a graph of reflectance-wavelength relationship for second beam splitter 160 and intensity-wavelength relationship for the band of red light L3r and the band of first light L1 in third light L3 for projection system 100 of FIG. 1. As shown in fig. 3, the second dichroic member 160 reflects most of the light having a wavelength shorter than the semi-transmissive wavelength thereof (i.e., the wavelength at which the reflectivity is 50% in fig. 3) and allows most of the light having a wavelength longer than the semi-transmissive wavelength thereof to pass therethrough. That is, the second beam splitter 160 shown in fig. 1 reflects most of the third light L3 and allows most of the first light L1 to penetrate therethrough. By adjusting the half-transmission wavelength of the second beam splitter 160, the ratio of the red light L3r of the first light L1 and the third light L3 merging into the integration rod 170 can be controlled. For example, adjusting the half-transmission wavelength of the second beam splitter 160 to be between the peak wavelength of the first light L1 and the peak wavelength of the third light L3 ensures that most of the first light L1 and the third light L3 are combined into the integration rod 170.

As shown in fig. 3, in the present embodiment, the red light L3r in the third light L3 has a wider wavelength range, and the first light L1 has a narrower wavelength range. In addition, the wavelength range of the first light L1 is within the wavelength range of the red light L3r in the third light L3, and the wavelength range of the first light L1 is greater than the peak wavelength of the red light L3 r. That is, the wavelength range of the first light L1 is included in the wavelength range of the red light L3 r. Therefore, if the first light L1 is transmitted through the second dichroic filter 160 and the third light L3 is reflected into the integrating rod 170, no matter how the semi-transmission wavelength of the second dichroic filter 160 is adjusted, the second dichroic filter 160 will remove a portion of the third light L3, and the whole of the first light L1 and the whole of the third light L3 cannot be combined into the integrating rod 170.

Specifically, if the half-transmission wavelength of the second dichroic filter 160 is made longer, the reflectivity of the second dichroic filter 160 to the third light L3 is increased, which affects the transmissivity of the first light L1. On the other hand, if the semi-transmissive wavelength of the second dichroic filter 160 is made shorter, the transmittance of the first light L1 is increased, but the reflectance of the third light L3 is decreased. Therefore, special consideration must be given to the design of the semi-transmissive wavelength of the second dichroic material 160.

Since the first light L1 emitted by the first light source 110 is a light with higher color saturation, in some embodiments, the first light L1 emitted by the first light source 110 can be designed to be completely retained. That is, when the position of the semi-transmission wavelength is outside the shortest wavelength in the wavelength range of the first light L1, the shortest wavelength in the full transmission band (i.e., the band in which the reflectance is 0% and R is 0%) of the second dichroic filter 160 is smaller than the shortest wavelength in the wavelength range of the first light L1. In this case, almost all (i.e., nearly 100%) of the first light L1 can pass through the second beam splitter 160. In other words, although part of the red light L3r is sacrificed by penetrating through the second dichroic member 160, the first light L1 with higher color saturation is incident into the integrator rod 170 instead. In this case, more first light sources 110 are required to make the white balance to the digital tv standard. It should be noted that the shortest wavelength in the above-mentioned full transmission band is called the critical transmission wavelength, and in another design of the light splitting element described below, the second light splitting element 160 reflects most of the light with a wavelength longer than the semi-transmission wavelength and allows most of the light with a wavelength shorter than the semi-transmission wavelength to pass through, and the longest wavelength in the full transmission band is also called the critical transmission wavelength.

In the present embodiment, a portion of the first light L1 emitted from the first light source 110 is removed from the design, and a portion of the first light L1 is incident into the integration rod 170. That is, the shortest wavelength (critical transmission wavelength) in the wavelength band (i.e., the full transmission wavelength band) in which the reflectance of the second dichroic material 160 is 0% is made to be between the wavelength ranges of the first light L1. In this case, part of the first light L1 is not merged into the integration rod 170, and this is compared with the embodiment that completely retains the first light L1 into the integration rod 170, and more of the third light L3 is merged into the integration rod 170. Since the intensity of the first light L1 is greater than the intensity of the third light L3, the intensity of the light incident into the integration rod 170 is lower than in the embodiment where the first light L1 is completely retained in the integration rod 170. Therefore, in the present embodiment, the first light source 110 can achieve white balance to the digital tv standard at a lower output power.

For example, in one embodiment, the wavelength of the first light L1 ranges from 637nm to 642nm, and the semi-transmission wavelength of the second beam splitter 160 is 629nm (the critical transmission wavelength is 637nm to 642 nm). Overall, the second light splitter 160 removes about 5.5% of the first light L1 from the first light source 110. However, in this case, after the projection system 100 achieves the digital video standard by adjusting the output power of the first light source 110, the output power of the first light source 110 is saved by 8.4% compared to the embodiment of completely retaining the first light L1 to the integration rod 170.

In another embodiment, the wavelength of the first light L1 ranges from 642nm to 646nm, and the semi-transmission wavelength of the second beam splitter 160 is 631nm (the critical transmission wavelength thereof ranges from 642nm to 646 nm). Overall, this embodiment also achieves similar effects, i.e. the second light splitter 160 removes about 5.5% of the first light L1 emitted from the first light source 110, and saves 8.4% of the output power of the first light source 110 compared to the embodiment that completely retains the first light L1 in the integration rod 170, on the premise that the digital video standard is achieved.

It should be understood that the above description is only exemplary, and one skilled in the art can make various modifications according to the practical requirements, and the present invention is not limited thereto. For example, in some practical designs, the second dichroic filter 160 may be designed to not remove a portion of the first light L1 and make the entire first light L1 incident on the integration rod 170 according to the intensity ratio distribution requirement of the green wavelength band and the red wavelength band in the third light L3.

Fig. 4 is a graph of transmittance versus wavelength for notch filter 190 of projection system 100 of fig. 1. Notch filter 190 may be located in integrator rod 170. In some embodiments, since the intensity of the green wavelength band in the third light L3 is higher than the intensity of the red wavelength band, a notch filter 190 may be further included in the projection system 100 to adjust the intensity ratio of the green wavelength band to the red wavelength band in the projection system 100. The notch filter 190 can reduce the intensity of the green band or the red band, respectively, thereby adjusting the intensity ratio of green to red in the projection system 100 to achieve better color balance.

In this embodiment, since the first light source 110 and the second light splitter 160 are designed to improve the intensity ratio of the green band to the red band in the projection system 100, the notch filter 190 only needs to slightly reduce the intensity of the green band in the projection system 100 to achieve the desired color balance.

Specifically, the notch filter 190 shown in fig. 4 may be used, which has semi-transmission wavelengths of 565nm and 586nm at both ends and has a minimum transmittance of less than about 40%. In the present embodiment, the notch filter 190 can achieve the digital video standard only by reducing the overall luminance by about 20%. In embodiments where the first light source 110 and the second light splitter 160 are not used, the notch filter 190 is used with a minimum transmittance of less than about 10%, and it is necessary to cut the overall brightness by about 40% to meet the digital video standard. That is, the first light source 110, the second light source 120, and the third light source 130 can be more effectively utilized in the present embodiment.

FIG. 5 is a top view of a projection system 100a according to another embodiment of the invention. Compared to the projection system 100 of fig. 1, the projection system 100a also includes a first light source 110, a second light source 120, a third light source 130, a wavelength conversion element 140, a first beam splitter 150, a second beam splitter 160, an integration rod 170, and an optical path adjusting element 180, and the elements and functions thereof are the same as those of the foregoing embodiments and are not repeated herein. In the present embodiment, the first light splitter 150 allows the first light L1 to penetrate through and reflect the fourth light L4. The second beam splitter 160 is designed to reflect most of the light having a wavelength longer than the semi-transmissive wavelength thereof and allow most of the light having a wavelength shorter than the semi-transmissive wavelength thereof to pass therethrough, and the maximum wavelength of the full transmission band thereof is the critical transmission wavelength. Therefore, the critical transmission wavelength of the second light splitter 160 is adjusted to be within the wavelength range of the first light L1, but a portion of the first light L1 is removed in a penetrating manner, and a portion of the red light L3r in the third light L3 is removed in a reflecting manner, so that a portion of the first light L1 and a portion of the third light L3 are combined into the integration rod 170, and thus, the above-mentioned effects of the present invention can be achieved.

FIG. 6 is a top view of a projection system 100b according to another embodiment of the invention. Compared to the projection system 100 of fig. 1, the projection system 100b also includes a first light source 110, a second light source 120, a wavelength conversion element 140, a first beam splitter 150, a second beam splitter 160, an integration rod 170, and an optical path adjustment element 180, and the elements and functions thereof are the same as those of the foregoing embodiments and are not repeated herein. However, the projection system 100b does not have the third light source 130 (i.e. does not have the fourth light L4), and further comprises the light distribution device 200. In addition, the first light splitter 150 allows a specific wavelength band of the first light L1 to pass therethrough, and removes other wavelength bands of the first light L1 in a reflective manner. As shown in fig. 6, the light distribution device 200 divides the second light L2 emitted from the second light source 120 into a first portion L2a and a second portion L2 b. The second light L2 of the first portion L2a passes through the optical path adjusting element 180, the second beam splitter 160 and the wavelength conversion element 140 in sequence. The second light L2 of the second portion L2b passes through the first light splitter 150 and the second light splitter 160 sequentially.

Specifically, the first light L1 and the second light L2 of the second portion L2b are incident on two opposite surfaces of the first light splitter 150, respectively. The first light splitter 150 allows the first light L1 to penetrate through and reflects the second light L2 of the second portion L2b, so that the first light L1 and the second light L2 of the second portion L2b are combined into a same light beam on the same side of the first light splitter 150. The light beam including the first light L1 and the second light L2 of the second portion L2b and the second light L2 of the first portion L2a are incident on the same side of the second light splitting element 160, and the second light splitting element 160 allows the first light L1, the second light L2 of the first portion L2a and the second light L2 of the second portion L2b to penetrate through. The second light L2 of the first portion L2a after penetrating through the second light splitter 160 is incident on the wavelength conversion element 140, and is converted into the third light L3 by the wavelength conversion element 140 and reflected to the other side of the second light splitter 160, at this time, the second light splitter 160 reflects the third light L3, so that the first light L1, the second light L2 of the second portion L2b, and the third light L3 are combined into a same light beam and incident on the integration rod 170.

In this embodiment, the second light L2 of the first portion L2a and the second light L2 of the second portion L2b both have the same wavelength range as the second light L2 before passing through the light distribution device 200, that is, the light distribution device 200 does not affect the wavelength of the passing second light L2. The light distribution device 200 distributes the energy of the second light L2 only. In the present embodiment, the light distribution device 200 allows a part of energy (e.g. 40% of energy) in the second light ray L2 to penetrate through to form the second light ray L2 of the first portion L2a, and reflects the remaining part of energy (e.g. 60% of energy) in the second light ray L2 to form the second light ray L2 of the second portion L2 b. In one embodiment, the light distribution device 200 can have different transmittance at different angles to achieve the light distribution effect, and specifically, the light distribution device 200 can be a neutral density filter (ND filter), but the invention is not limited thereto.

In the present embodiment, the critical transmission wavelength of the second light splitter 160 is also adjusted to be within the wavelength range of the first light L1, and a portion of the first light L1 is removed in a reflective manner, and a portion of the red light L3r in the third light L3 is removed in a transmissive manner, so that a portion of the first light L1 and a portion of the third light L3 are combined into the integration rod 170, and thus, the above-mentioned effects of the present invention can be achieved.

FIG. 7 is a graph showing intensity versus wavelength for each light of the projection system 100b of FIG. 6. The peak wavelengths of the light beams are the second light beam L2, the third light beam L3 and the first light beam L1 in sequence from small to large. In this embodiment, since the third light source 130 emitting the fourth light L4 (with a peak wavelength of about 462nm) is not provided, the blue light is only emitted from the second light L2 (with a peak wavelength of about 455nm) emitted by the second light source 120, so that the overall color tone of the projection system 100b is more blue-violet with a shorter wavelength than that of the

projection systems

100 and 100 a. In addition, the third light source 130 is removed, so that the volume of the projection system 100b can be reduced, and the system can be simplified.

FIG. 8 is a flowchart illustrating an adjustment method 210 of the projection system 100 of FIG. 1. It should be appreciated that the same concepts may also be applied to the

projection systems

100a, 100b shown in fig. 5 and 6, respectively, and only the projection system 100 is illustrated for convenience of illustration. As described above, the projection system 100 shown in FIG. 1 can be optimized by adjusting the semi-transmissive wavelength of the second beam splitter 160, so that the projection system 100 can achieve the digital video standard under the operation of lower power. How to obtain a specific value of the semi-transmission wavelength of the second dichroic filter 160 will be described below with reference to fig. 8.

As shown in fig. 1 and 8, in the adjusting method 210, in step S220, a portion of the first light beam L1 and a portion of the third light beam L3 are removed by using the second light splitter 160. In step S220, a boundary value is determined, and the portion of the first light L1 with a wavelength smaller than the boundary value is removed, and the portion of the third light L3 with a wavelength larger than the boundary value is removed. Specifically, reference may be made to the embodiment shown in fig. 3 using a dichroic mirror as the second beam splitter 160.

As shown in fig. 3 and 8, in step S220, the half-transmission wavelength of the second beam splitter 160 is between the peak wavelengths of the first light L1 and the third light L3. For example, if the peak wavelength of the first light L1 is 635nm and the peak wavelength of the third light L3 is 620nm, the semi-transmissive wavelength of the second dichroic filter 160 is set to be between 620nm and 635 nm. In the present embodiment, the semi-transmissive wavelength of the second dichroic filter 160 is set to 620 nm.

As shown in fig. 1 and 8, step S230 is performed to adjust a first removal amount of the first light beam L1 and a second removal amount of the third light beam L3. As described above, as the half-transmission wavelength of the second dichroic filter 160 changes, the reflectivity of the first light L1 and the transmissivity of the third light L3 change accordingly. That is, the first removal amount of the first light L1 and the second removal amount of the third light L3 can be adjusted by adjusting the boundary value in the step S220.

Specifically, since the semi-transmissive wavelength of the second dichroic material 160 has been set to the extreme value of 620nm in step S220, the semi-transmissive wavelength of the second dichroic material 160 may be changed in units of 1 nm. That is, in step S230, the half-transmission wavelength of the second dichroic filter 160 is changed to 621 nm.

As shown in fig. 1 and fig. 8, step S240 is performed to adjust the power of the first light source 110 so that the color saturation and the white balance of the projection system 100 reach the predetermined standard. Specifically, this default standard may be the digital movie standard. In step S240, the required output power of the first light source 110 when the projection system 100 reaches the digital tv standard is recorded.

As shown in fig. 1 and 8, step S250 is performed, and step S230 and step S240 are repeated to find the lowest value of the power output by the first light source 110. That is, the power required to be output by the first light source 110 when the semi-transmission wavelength of the second beam splitter 160 is 622nm and 623nm … 635nm is reached to the digital video standard is sequentially tested, and the lowest value of the power output by the first light source 110 is found.

After the steps S220 to S250, the second light splitter 160 corresponding to the lowest output power of the first light source 110 may be adopted, so that the projection system 100 may operate in a power-saving output state. In some embodiments, it is not necessary to use the second light splitter 160 corresponding to the lowest output power of the first light source 110, and the second light splitter 160 should be selected according to practical requirements.

In some embodiments, the intensities of the first light L1 and the third light L3 can be weighted by the tristimulus values of the human eye, and the most suitable half-transmission wavelength of the second beam splitter 160 can be directly calculated. Then, fine adjustment is performed based on the semi-transmission wavelength to find an optimum value.

It should be understood that the above description is only exemplary, and the present invention is not limited to the above description. For example, some steps may be omitted or additional processes may be added before, during or after the above steps, depending on the practical requirements.

In summary, the

projection systems

100, 100a, 100b can reach the Digital television standard (DCI) at a lower power with the aid of the first light source 110, and effectively reduce the risk of heat fading caused by over-high power of the light source. In addition, the second dichroic material 160 is selected to make the intensity ratio, white balance and color gamut of red, green and blue colors in the

projection systems

100, 100a, 100b more easily reach the digital video standard. In addition, the present invention also provides an adjusting method 210 of the

projection systems

100, 100a, and 100b, which considers the problem of human eyes recognizing tristimulus values of three primary colors in addition to the color intensity, and effectively improves the operating efficiency of the

projection systems

100, 100a, and 100 b. Finally, the

projection systems

100, 100a, 100b and the adjustment methods thereof are compatible with the prior art, and the technical effects can be obtained without extra large cost.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A projection system, comprising:

a first light source for emitting a first light;

a second light source for emitting a second light;

a wavelength conversion element for converting part or all of the second light into a third light, wherein the third light comprises a red light and a green light, the wavelength range of the first light is within the wavelength range of the red light, and the wavelength range of the first light is greater than the peak wavelength of the red light;

a first light splitter for transmitting or reflecting the first light; and

a second light splitting component for removing part of the red light and having a critical transmission wavelength, wherein the critical transmission wavelength is located in or out of the wavelength range of the first light to remove part of the first light or not to remove the first light;

the second light is transmitted or reflected by the second light splitting part and then directly enters the wavelength conversion element; the first light ray sequentially passes through the first light splitting part and the second light splitting part, the second light ray sequentially passes through the second light splitting part and the wavelength conversion element, is converted into third light ray, returns to the second light splitting part, and is reflected by the second light splitting part.

2. The projection system of claim 1, wherein the peak wavelength of the second light is less than the peak wavelength of the third light, and the peak wavelength of the third light is less than the peak wavelength of the first light.

3. The projection system of claim 1, further comprising:

the light distribution device divides the second light into a first part and a second part, and the wavelength conversion element converts the second light of the first part into the third light.

4. The projection system of claim 3, wherein the first portion of the second light beam passes through the second beam splitter, the wavelength conversion element and the second beam splitter in sequence, and the second portion of the second light beam passes through the first beam splitter and the second beam splitter in sequence.

5. The projection system of claim 3, wherein the first beam splitter combines the first light and the second portion of the second light, and the second beam splitter combines the first light that is not removed, the second portion of the second light, and the third light that is not removed into a white light.

6. The projection system of claim 5, further comprising an integration rod, wherein the white light is incident into the integration rod.

7. The projection system of claim 1, further comprising a third light source emitting a fourth light.

8. The projection system of claim 7, wherein the fourth light beam passes through the first beam splitter and the second beam splitter in sequence.

9. The projection system of claim 7, wherein the peak wavelength of the second light is less than the peak wavelength of the fourth light, the peak wavelength of the fourth light is less than the peak wavelength of the third light, and the peak wavelength of the third light is less than the peak wavelength of the first light.

10. The projection system of claim 7, wherein the first beam splitter combines the first light and the fourth light, and the second beam splitter combines the first light that is not removed, the third light that is not removed, and the fourth light into a white light.

11. The projection system of claim 10, further comprising an integration rod, wherein the white light is incident into the integration rod.

12. The projection system of claim 1, wherein the second beam splitter is a dichroic mirror and has a semi-transmissive wavelength between a peak wavelength of the first light and a peak wavelength of the third light.

13. The projection system of claim 12, wherein the first light has a wavelength ranging from 637nm to 642nm, and the semi-transmissive wavelength of the second beam-splitting element is 629 nm.

14. The projection system of claim 12, wherein the first light has a wavelength ranging from 642nm to 646nm, and the semi-transmissive wavelength of the second beam splitter is 631 nm.

15. The projection system of claim 1, further comprising a notch filter having semi-transmissive wavelengths of 565nm and 586nm, respectively, and a minimum transmittance of less than 40%.

16. A method of adjusting a projection system as claimed in claim 1, comprising the steps of:

(a) removing a part of the first light and/or a part of the third light by using the second light splitting part;

(b) adjusting a first removal amount of the first light and a second removal amount of the third light;

(c) adjusting a power of the first light source to make a color saturation and a white balance of the projection system reach a preset standard; and

(d) repeating the steps (b) and (c) to find the lowest power of the first light source.

17. The method of claim 16, wherein step (a) further comprises:

defining a boundary value, removing the part of the first light ray whose wavelength is less than the boundary value, and removing the part of the third light ray whose wavelength is greater than the boundary value.

18. The method of claim 17, wherein the cut-off value is between the peak wavelength of the first light and the peak wavelength of the third light.

19. The method of claim 18, wherein step (b) further comprises:

adjusting the first removal amount of the first light and the second removal amount of the third light by adjusting the boundary value.

20. The method of claim 19, wherein step (b) further comprises:

weighting the first removal amount of the first light and the second removal amount of the third light by the tristimulus values, and calculating the most appropriate boundary value.