TW200933071A - Multi color light source - Google Patents

Abstract

The present invention relates to a multi color LED based light source, at least comprising several light emitting elements (1, 2, 3) emitting light beams (5, 6, 7) of different colors, a beam combining optics arranged for combining said light beams (5, 6, 7) to a combined light beam (8), and at least two light sensors (11, 12, 13) arranged at separate locations to measure fractions of light emitted by said light emitting elements (1, 2, 3). The beam combining optics comprises a first wavelength selective element (9) transmitting light of a first (1) of said light emitting elements (1, 2, 3) in a first wavelength region and reflecting light of a second (2) of said light emitting elements (1, 2, 3) in a second wavelength region. A first (11) of said sensors (11, 12, 13) is arranged to measure light of said first light emitting element (1) reflected at said first wavelength selective element (9) and/or to measure light of said second light emitting element (2) transmitted through said first wavelength selective element (9). With the proposed multi color light source cheap light sensors can be used to reliably control the spectral output of the light source.

Description

200933071 IX. Description of the Invention: [Technical Field] The present invention relates to a multi-color light source comprising at least a plurality of light-emitting elements that emit light beams having different colors, and in particular, LEDs (LEDs: light-emitting diodes) a beam combining optics configured to combine the beams into a combined beam that combines optical, 11 pieces comprising at least one first-wavelength selective element that transmits in the -first wavelength region And the light of the first one of the light-emitting elements and the second light of the light-emitting element such as θ in a second wavelength region; and the light sensing g& Part of the light to allow control of the intensity and color output of the combined beam. Light sources based on multi-color LEDs can be used in applications that require highly concentrated, full-spectrum light. Examples of such applications are concentrated illumination and digital projection. In order to produce a light source for such applications, the emission of LEDs having a plurality of different colors is combined by beam combining optics, for example, the configuration of a dichroic mirror or cube, and the spectrum emitted by such a source. It is controlled by the power ratio of the separated LEDs. [Prior Art] - The use of LEDs in light sources for illumination or projection applications not only has advantages. * One of the main drawbacks of led is that its emission spectrum depends on temperature. Therefore, not only the efficiency of an LED emission but also its wavelength varies with temperature, drive current, and component lifetime. This requires complex sensing of the light emitted by the different LEDs in order to achieve a constant color output of the combined beam. US 2006/0215122 A1 describes an image projection apparatus for adjusting the white balance in consideration of the level of light 133904.doc -6 - 200933071 emitted from the LED. The image projection device includes a light source unit for sequentially emitting light generated by a red, a green, and a blue light emitting element. A beam combining optics combines the beams of the different illuminating elements into a combined beam. A photosensor disposed on the optical path of the combined beam measures the level of light generated by the different illuminating elements. A controller controls the emission of the light-emitting elements based on the measurement of the level of light measured by the light sensor to adjust the white balance of the image projected by the image projection device. The measurement of the spectral shift of light emitted by the illumination elements in an image projection device requires an appropriate illuminator for the red, green and blue wavelength ranges. In order to avoid changing the filter during operation, a two-channel photosensor is known for this measurement task. This three-channel photosensor is a very expensive component. Moreover, such filters for such sensors are typically of limited quality. The aging and temperature behavior of these sensors and filters is largely unknown or worse than needed. The filter characteristics also depend on the angle of incidence of the light, which is fine tuned when the sensor is used in the path. SUMMARY OF THE INVENTION One object of the present invention is to provide a multi-color shirt light source based on light-emitting elements having different colors, wherein a sensing configuration for controlling the spectral output of the light source provides a high reliability of measurement and can be low in cost. achieve. This object is achieved by a multi-color light source according to claim 1. Advantageous embodiments of this light source are the subject matter of these independent claims and are described in subsequent sections of this specification. 133904.doc 200933071 The proposed multi-color light source comprises at least a plurality of light-emitting elements emitting light beams having different colors, in particular a led; beam combining optics configured to combine the beams into a combined beam And at least two photosensors disposed at the separated position to measure a portion of the light emitted by the light emitting elements, the beam combining optics comprising at least one first wavelength selective element at a first wavelength Light in the region that transmits the first of the light-emitting elements and reflects light from the second of the light-emitting elements in a second wavelength region. The first of the sensors is configured to measure light reflected by the first light emitting element at the first wavelength selective element and/or to measure transmission of the second light emitting element through the first wavelength selective element Light. Due to this configuration of at least one of the sensors, the wavelength selection properties of the wavelength selective element are also used for the sensor. This avoids the need for any additional wavelength selective filters in front of the sensor. By appropriately arranging the different sensors in the multi-color source, all of the information needed to control the illumination elements to achieve the desired spectral characteristics of the output of the source can be made simple and inexpensive. The sensor is implemented without any filters. The number of sensors required depends on the number and nature of the light-emitting elements in the light source. For example, if one or more of these light-emitting elements do not exhibit any wavelength shift with temperature, then more must be provided. There are fewer sensors because only the strength of these or a plurality of illuminating elements is measured. In addition, when the different light-emitting elements are sequentially operated, which is the case for a general projection application, the non-sequential operation of the light-emitting elements, that is, one of the elements in which all of the elements are simultaneously operated, is continuous Operational comparisons also require fewer sensors. However, in this continuous operation, it is also preferable to include a measurement period in which the light-emitting elements are sequentially switched in 133904.doc 200933071. Therefore, this operation also requires fewer sensors. The proposed multi-color light source preferably also provides a controller for controlling the required intensity and color output 〇/徇® heat of the combined light beams of the light-emitting elements based on the measurements of the light sensors, and possibly The system provides the proposed multi-color source without this controller. In this case, the multi-color light source must be connected during operation to - the appropriate control (four) ^, the controller of the digital imaging device' in which the light source is mounted. In the proposed multi-color light source, the sensors are configured such that they benefit from the wavelength selection properties of the already included wavelength selective elements of the light source. By the appropriate combination of sensor positions, the emission properties of the illuminating elements, as well as the (four) degrees and the money loss, are calculated from the different measurements. This requires the "calibration" of the measurement system before operation. In this-calibration, the measurements of the sensors are related to the intensity and wavelength characteristics of the separation measurements at different operating temperatures of the illuminating elements. The result is a table or matrix in which the correlations of the measurements are recorded. This calibration is preferably performed after the manufacture of the light source and prior to its first use, but may also be part of the design and measured on the same board. However, if desired, the multi-color source can be recalibrated at any later time. The controller for controlling the light output of the light source then controls the light emitting elements based on the measured values of the light sensors and the matrix data above. Since the sensors utilize the spectral characteristics of the high quality wavelength selective elements of the beam combining optics, high quality measurements of the wavelengths are ensured. Therefore all light sensors can have the simplest style. Older I33904.doc 200933071 Chemical and temperature offsets do not cause significant problems because all sensors can have the same pattern. Since the sensors are already part of the proposed multi-color source, the present invention provides a fully usable illumination module. The wavelength selective element or the wavelength selective elements of the beam combining optics may be used for the above measurements because the wavelength selective element still allows light in this wavelength region when designed for reflection in a particular wavelength region The small amount of transmission allows for an even greater amount of transmission in the nearby wavelength region. Since the LED has a relatively wide emission, some of the light on the side of the emission curve is always transmitted through the reflective element. This is also the case for the reflection of the portion of the light emitted by an LED at the wavelength selective transmission element. This residual light is detected and measured by the light sensors in accordance with the present invention. By combining the measurements of the different photosensors, the desired information about the wavelength shift or intensity shift of the LEDs can be derived. In a preferred embodiment, the need for a wavelength shift is required. Information is achieved by forming a ratio of measured values of at least two appropriately positioned sensors. In an embodiment comprising a light source comprising three light-emitting elements of different colors, the beam combining optics comprises two wavelength selective elements for forming the combined light beam. The first wavelength selective element is in a first wavelength region Light transmitted through the first illuminating element and reflecting light of the second illuminating element in a second wavelength region. The second wavelength selective element transmits light in a first wavelength region and a second wavelength region (typically in a larger wavelength region including the first wavelength region and the second wavelength region) and is in a third wavelength region Light reflecting the third light emitting element. This beam combining optics is known in the art, for example, in an rgb (rgb: red green blue) source. 133904.doc 200933071 In this embodiment and other embodiments of the proposed multi-color source, the wavelength selective elements of the beam combining optics are preferably dichroic mirrors. In this embodiment, three photo sensors are disposed inside the housing of the light source. The first photosensor is configured to measure light reflected by the first illuminating element at the first wavelength selective element and to measure light transmitted by the second illuminating element through the first wavelength selective element. The second photosensor is configured to measure light reflected by the first and second illuminating elements at the second wavelength selective element and simultaneously measure transmission of the third illuminating element through the second wavelength selective element Light. The third sensor is configured to measure the combined beam, for example by focusing light reflected at a beam disposed in an optical path of the combined beam. For example, the reflective surface can be the surface of a collimating lens. While these surfaces are meant to be non-reflective, the residual reflection provides sufficient signal for light measurement. Furthermore, if a sufficient amount of light of the combined beam is reflected or scattered from the surface, any other surface inside the source can be used. When the three different light-emitting elements are operated in sequence, the complete measurement of any intensity or wavelength shift of the three light-emitting elements can be achieved using the measurements of the three sensors. For example, the proposed photosensors used in the multi-color source can be simple photodiodes that do not require any additional wavelength selective filters on or in their light sensitive areas. . One of the proposed multi-color light sources primarily applies coefficient bit projection, for example, in the form of a portable projector, rear projection τν, and the like. The proposed multi-color light source can also be used, for example, in a theater or in concentrated lighting applications for active lighting where a high beam quality color is required 133904.doc 200933071 color control light. For such applications, the multi-color source preferably includes a simple application that fully integrates the controller so that the customer can use the source. These and other aspects of the invention can be seen in the examples described hereinafter and are set forth by reference. [Embodiment] The proposed multi-color light source is hereinafter described by way of example without limiting the scope of protection defined by the claims. Figure 1 shows a schematic representation of a first example of one of the proposed multi-color sources. The light source comprises two LEDs: a red LED 1, a green LED 2 and a blue LED 3. The light emitted by the different LEDs is collimated by a beam collimating optics 4 disposed at the periphery of each of the LEDs to form a red beam 5, a green beam 6, and a blue beam 7. The beams are combined into a combined beam 8 by a beam combining optics, which in this example comprises two dichroic mirrors 9, 1 〇 „ these dichroic mirrors mix the three LED light, which may also be formed by a known LED module having a plurality of side-by-side LEDs of the same color. However, the first dielectric mirror 9 is coated such that it only reflects, for example, from Green light in the wavelength region of 500 to 590 nm. The second mirror has a coating for reflecting, for example, blue light in a wavelength region from 400 nm to 500 nm. A dielectric mirror 9 is designed to be primarily transparent in the wavelength region of light emitted by the red LED 1. The second dielectric mirror 10 is designed to allow the red LED 1 and the green LED 2 Transmission of red and green light emitted. Since the LED has a relatively wide transmission, a small amount of the 133904.doc -12-200933071 light system of the green LED 2 is not reflected by the first dichroic mirror 9, and at the same time Some of the light beams emitted by the red LED i are reflected at the dichroic mirror 9. This transmission and reflection The amount of light is strongly dependent on the actual emission profile of the LEDs 1, 2. If the dominant wavelength of the red LED 1 is shifted to a shorter wavelength due to temperature or varying power, the reflected light is more intense. The first photosensor 丨丨 is suitably placed at a position where the reflected light is collected. The three photo sensors 12, 12 and 13 are placed in the three separate directions indicated in the figure. Positional 'measures information about all three LEDs. Because there is always a lot of extra reflection and diffraction inside the outer casing of this multi-color light source, the placement of these sensors is not important, even if it is The light outside the main beam is extremely high, so the light system is sufficient for measurement. Even the useful life of the sensors has only a reduced light level. The first sensor 12 is Light that is configured to accumulate the red led 1 and the green LED 2 in a wavelength range below 480 nm, which is reflected at the second dichroic mirror 10. This second sensor 12 also accumulates The blue LED 3 emits and is not in the second dich in the wavelength range above 480 nm The light reflected at the mirror 10. Thus the sensor signal of the second sensor 12 and the red "blue" of the red LED 1 are emitted and the "blue" of the green lEd 2 is emitted, but the amount The field has a correlation with the green and red (or yellow) components of the blue LED 3. The sensor signal of the first photo sensor 11 and the red LED 1 having an additional signal from the "red" (and possibly "blue") component of the green LED 2 " (and possibly "blue") emissions have a relationship. The second photo sensor 13 is positioned to accumulate light of the combined beam 8 reflected at the lens surface of the beam concentrating optics 14 of the source. Therefore, 133904.doc •13· 200933071 The sensor signal of the third photo sensor 13 is closely related to the output light level of the light source, that is, the blue component of the blue LED 3, the green color of the green LED 2 Component and the red component of the red LED 1. These responses are measured after design or manufacture and the coefficients can be placed in a systematic matrix. Due to this system matrix, the current characteristics of each LED can be measured. The offset of the wavelength of each LED is then detected as a change in the relationship between the different photosensor signals, which corresponds to a relationship: light in the nearby ribbon/light in the target ribbon.

Ο Although the spectral separation of these sensors is limited, these measurements allow for a complete analysis of the emission characteristics of these LEDs and will not change the system lifetime. As an example, the following calculations can be completed when simplification of the following ideal conditions is assumed. The LEDs used may have the spectral properties shown in Figure 3. The dichroic mirrors 9 and 1 can have the transmission/reflection properties as shown in FIG. 4 (reflectance=1-transmittance, the spectral sensitivity of the sensors, Srei==f(^) is shown in FIG. 5. The signal on each sensor can be calculated by multiplying the integral of the sensor sensitivity by all the transmittance and reflectivity' and multiplying by the output of the Led on the complete spectrum. Intensity / luminous flux Pr' Pb, Pg = emission power spectrum

Re = reflectivity (where the dichroic filter is usually equal to _ _ Τ γ) Τ γ = transmittance S = relative sensitivity Ϊ a v 700nm wn (ah = ks - one "coffee *) I, 400nm I33904.doc 200933071 700nm

Isensorl2(LEDl) = kScaIe plus ·12 * IL£D1 * |^Γ(λ) TlMim>r9(X) ®-eMinorlO(X) Ssensorl2(X)^ 700nm

ASensor!3(L£D2) _ ^Scale^ensorU kscale^Scnsor丨3 * IlED丨 * /^Γ(λ) ReL«isSuifecel4(X) ^Sensorl3(X)^ 700 ran

Isensorl1(LED2) = ^Scale^Sensorll *^LED2 * JP^(X)TrMiiT〇r9(X)Sscnsorl\(λ)^ 400nm 700nm

Isensorl2(LK)2) " ^Scale^ensor12 * ^LED2 * |^(λ) ^βΜιιΐϊ>Γ9{λ) ^eMim>r10(X) Ssensorl2(X)^ 400nm 700iun ^SensorI3(LED2) = ^Scale ^ensorl3 * IlED2 * |^(λ) ^eMim>r9(X) ΤΓΜίπ〇Γΐ0(λ) ^UnsS^eUiX) Ssensorl3(X)^ 400nm ❹ LSensorll(LED3) 700nm lScnsorl2(LED3) ^ ^Scale^ensor12 LLED3 JPg(X)TrMiiT〇rlO(X)Ssensorl2(X)^ 700nm

Is«nsorl3(LED3) = kscaie>SensOTl3 * 1 coffee 3 * fPg(8) ReMinor丨. (λ) ReLensSurfaee14(l) SsensorU(X)dX The integral part of the equations can be treated as a constant as long as there is no change in the spectrum of the LEDs. In this case, the system can be expressed as a linear equation group. Due to the three sensor currents, the luminous flux of the three LEDs can be calculated as a solution to this equation. This task does not require the support of these LEDs.

Order operation. —k" k,2 0 " Iledi Ϊ = Sensor k2i ^22 ^23 IlED2 _k3i ^32 ^33 _ _IlED3_ The process flow is as follows: Design / Manufacturing - Calculation or measurement constant knm - Calibration sensor signal - Calculation and Save Reverse System Matrix -15- 133904.doc 200933071 Operation

- Operate the LED - Measure all sensor signals - Calculate the luminous flux of all LEds using the stored matrix. In addition, if the spectral component of the LED light also needs to be measured, it needs to be made during the phase in which only one LED is powered. Measurements (where linear overlaps and slightly more complex calculations or measurements of two LEDs (one LED is always off) are possible). The LED 2 is used here as an example. Figure 6 illustratively shows the power spectrum of this LED at two different operating currents. For example, a chirped photodiode system is used as the sensor and the sensitivity is estimated to be a wavelength range of 4 nanometers to 7 nanometers by a linear function. Where λ is at the nanometer level: Ssens〇r (^=〇〇〇2333λ _ 〇8333 For mirrors 9 and 10, the system used has an ideal filter function for each edge: - mirror 9 100 ° /. reflection < 6 〇〇 nanometer wavelength and 1〇〇% transmission wavelength above • Mirror 10 100% reflection < 480 nm wavelength and 1 〇〇. /. Above the transmission wavelength of the optical device 14 has a 2.5% Residual reflections. In this example, the sensor signals measured in the application or calculated using the above equation are: S11.1400mA = 2.896χ 10 4 Sllil00mA = 4.382χ 10~5 S12_1400mA= 1·357χ 10 3 S12 .i〇0mA = 2.211x 10~5 S13.1400mA=l-543x 10 3 S13.100mA = 2.34x 10~4 The results can be evaluated by normalizing the measurement: 133904.doc -16* 200933071

1400 mA normalized to 13 100 mA normalized to 13@14〇〇 〇iA 100 mA normalized to 13

S11.1400mA Λ -=0.188 Sn.ioomA S13.1400mA Si3.1400mA s 12.1400mA ... -=0.879 Sl2.100mA s13.1400mA S13.1400mA ^13.1400mA Sl3.100mA ^13.1400mA Sl3.1400mA

0.028 S11.100mA -=0.187 s13.100mA 0.014 S12.100mA Λ one -=0.095 s13.100mA 0.152 s13.100mA , S13.100mA Now if you want to evaluate the light intensity and color shift, you must select two letters

number. The best signal in this example is from sensors 12 and 13. The k-number of the sensor 13 is already close to the luminous flux. The ratio of 12/13 is greatly affected by the color shift; its 0.879 at full-charge current changes to 0.095 at low current. The proposed system first analyzes the ratio of 12/13 and uses a lookup table (which contains the relationship between color points and 12/13, which is calculated or measured during the design or manufacture of the system. Or this The current color point is determined by the help of a model function suitable for this behavior. In a second step, the light (4) is calculated based on the sensor signal of the device 13 (optionally with the correction factor stored in the same lookup table). . For this example, a...% of the team. Tethering is an indication of the smaller spectral width due to lower current emissions. If this change in the spectral width is also changing, for example, caused by different offsets caused by m, J, and the current, then a second-element main-spot lookup table and the signals 12/ 13 and I33904.doc 200933071 11/13 can still be used to measure accurate color points (general rule: each independent variable analyzes an independent measurement signal). The process flow is as follows: Design / Manufacturing • Calculate or measure the color change and the correlation between the ratio 12/13 (if needed and li/i3) - Calculate or measure depending on the color for flux measurement 丨3 Correction factor

- Compile the lookup table or design approximation function for color point and flux correction - Pulse only for LED 2 - Measure all (or only 12 and 13) sensor signals - Calculate quotients 11/13 and 12/13 ( Or only 12/13) - self-finding table or model function to determine color point and brightness correction factor - use signal 13 and correction to calculate luminous flux _ (use light flux and color point results to correct light output to target light and color) Figure 1 shows a An example wherein the three LEDs display a wavelength shift depending on temperature and an intensity shift during operation. When one or two LEDs are used without any temperature dependent offset, then the measurement requires, for example, a special type of phosphor converted LED for red and green light, or even fewer sensors. This is shown in the schematic of Figure 2, where the red Led i and the green LED 2 do not show any temperature-dependent diurnal (four) wavelength shifts that must be compensated. For these LEDs, only the emission intensity is beneficial. Combining this with a conventional blue LED requires only sensors 12 and 13 to gather the measurement data needed for proper control of the light such as 133904.doc 200933071. The controllers 1 and 2 also schematically show the controller 15 which is connected to the optical sensors 11 to 13 and is connected to the driving units of the LEDs to 3. The drive units are not separated from these figures. Control of the different LEDs can also be accomplished by combining at least one of the at least two LEDs that are slightly offset in color in the source. For example, the blue LED module 3 from a different wavelength batch of blue LEDs is mixed and a separate driver for the two LEDs is provided, which allows for a completely stable color lighting module. The desired color can always be achieved by properly balancing the outputs of the two LEDs. Due to the separate short pulses on each of the two different blue LEDs and the analysis of the sensor signals 12 and (3 (as previously explained)', the color coordinates of both blue LEDs can be determined. Depending on these color coordinates, the balance between the two is set to achieve the desired mixed color point. Finally, the sensor signal 13 for the spectral offset of the two LEDs and an optional correction factor (from the lookup table using the signal 12/13) can be used to adjust the level of the two LEDs to the desired brightness. . This greatly reduces the design effort of all projector manufacturers. Alternatively, the measurement can be used to display such source properties for compensation by downstream pictures or light processing components. Digital projection and spotlight illumination require a high power, low etendue source with precisely controlled color balance. A commonly used optical solution is a combination of color choices of multiple beams that are reflected by dichroic colors. By adding such light sensors at selected locations in accordance with the present invention in such a configuration, the sensors can acquire color and brightness information without having their own filters. Based on this, it is possible to design a complete lighting module with a corrected light output of 133904.doc -19-200933071. Expensive and unreliable color sensor system is omitted ^

The present invention has been described and described in detail in the drawings and the claims. The various embodiments described in the above description and claims may also be combined. It will be apparent to those skilled in the art that <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; More than one LED may be provided in the multi-color light source as exemplified by t'. Moreover, the position of the sensors for light measurement is not limited to the positions shown in the figures. The sensors must be configured to use the wavelength selection of at least one of the wavelength selective components of the beam combining optics to allow for the desired information to be derived from the different sensors. In the claims, the word "comprises" does not exclude other elements or steps, and the indefinite article &quot;a&quot; does not exclude plurals. The fact that the method is described in separate claim items does not indicate that it is not available. The combination of these methods yields benefits. 4 Any reference in the solution should not be construed as limiting the scope of such claims. [Simplified Schematic] Figure 1 is a proposed three-sensor with three photosensors. Schematic diagram of one example of the multi-color light source, ' FIG. 2 is a schematic diagram of another example of the proposed multi-color light source having two photo sensors; FIG. 3 is a spectrum of three LEDs having different colors An example of output; I33904.doc -20- 200933071 Figure 4 is an example of the transmittance of two different dichroic mirrors; Figure 5 is an example of the spectral sensitivity of a standard Shixia photodiode; Figure 6 is an example of the power spectrum of a green LED at two different operating currents. [Key Symbol Description] ❹

1 red LED 2 green LED 3 blue LED 4 beam focusing optics 5 red beam 6 green beam 7 blue beam 8 combined beam 9 first dichroic mirror 10 second dichroic mirror 11 first photo sensor 12 second Light sensor 13 third light sensor 14 beam collecting optics 15 controller 133904.doc

Claims (1)

200933071 X. Patent application scope: 1 · A multi-color light source, which at least comprises: a plurality of light-emitting elements (1, 2, 3), which emit light beams (5, 6, 7) having different colors; _ a combination of light beams An optical device configured to combine the beams (5, 6, 7) into a combined beam (8), the beam combining optics comprising at least one first wavelength selective element (9), Light in the first wavelength region that transmits the first light-emitting element (1) of one of the light-emitting elements (1, 2, 3) and reflects the light-emitting elements (1, 2, 3) in a second wavelength region Light of a second illuminating element (2); at least two photo sensors (u, 12, π)' are arranged at separate positions for measuring emission by the illuminating elements (1, 2, 3) One of the light's one of the first sensors (11, 12, 13) is configured to measure the first light-emitting element (1) at the first wavelength-selective element (9) Reflecting light and/or measuring light transmitted by the second light-emitting element (2) through the first wavelength selective element (9). 2. The light source of claim 1, wherein the beam combining optics comprises a second wavelength selective element (10) that transmits light at least in the first wavelength region and the second wavelength region and in a third wavelength region Reflecting light of one of the third light-emitting elements (3) of the light-emitting elements (1, 2, 3), wherein one of the sensors (11, 12, 13) is a second sensor (12) Configuring to measure light reflected by the first and second light emitting elements (1, 2) at the second wavelength selective element (10) and/or to measure transmission of the third light emitting element (3) through the second Light of the wavelength selection element (1〇). 133904.doc 200933071 3. The light source of claim 1 or 2, wherein one of the sensors (11, 12, 13) and the sensor (13) are configured to measure one of the interior of the light source The light of the combined beam (8) reflected and/or scattered by the surface. 4. The light source of claim 3, wherein a transmitted beam forming optic (14) is disposed in an optical path of one of the combined beams (8) and the sensors (11, 12, 13) are Another sensor (13) is configured to measure light reflected from one of the surfaces of the beam forming optics (14). 5. The source of claim 3 wherein one of the reflected beam forming or beam deflecting optics is disposed in one of the combined beams (8) and the sensors (11, 12, 13) The other sensor (13) is configured to measure light transmitted through the beam forming optics (14). 6. The source of claim 1 or 2 wherein the wavelength selection component (9, 1) is a dichroic mirror. 7. The light source of claim 1 or 2 wherein the sensors (11, 12, 13) are configured to select elements (9, 1 〇) and the sensors (丨 1, 12) There is no color filter between the sensing areas of 13). 8. The light source of claim 2 wherein the light-emitting elements (1, 2, 3) comprise at least one red LED, one green LED and one blue LED. 9. The light source of claim 1 or 2, further comprising a controller (is) for controlling the light-emitting elements based on measurements of the light sensors (11, 12, 13) (1, 2, 3) The emission is to achieve the desired intensity and color of one of the combined beams (8). A light source as claimed in claim 9, wherein the controller (15) controls the power of the light-emitting elements (1, 2, 3). 133904.doc -2 - 200933071 U. The light source of claim 9, wherein the controller (15) has access to calibration data that causes measurements of the photosensors (1), 12, 13) It relates to the intensity and wavelength information of the light-emitting elements (1, 2, 3). τ 径 荔 荔 15 15 15 】 】 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 如 请求 请求 请求 请求 请求The source of the request item i - the type of projector # 'which includes at least one source such as the request item i 133 133904.doc