WO2014106439A1 - 投影装置 - Google Patents

投影装置 Download PDF

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Publication number
WO2014106439A1
WO2014106439A1 PCT/CN2013/090222 CN2013090222W WO2014106439A1 WO 2014106439 A1 WO2014106439 A1 WO 2014106439A1 CN 2013090222 W CN2013090222 W CN 2013090222W WO 2014106439 A1 WO2014106439 A1 WO 2014106439A1
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WO
WIPO (PCT)
Prior art keywords
laser
liquid crystal
light
ferroelectric liquid
crystal light
Prior art date
Application number
PCT/CN2013/090222
Other languages
English (en)
French (fr)
Inventor
李屹
杨毅
Original Assignee
深圳市光峰光电技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication of WO2014106439A1 publication Critical patent/WO2014106439A1/zh

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/005—Projectors using an electronic spatial light modulator but not peculiar thereto
    • G03B21/006—Projectors using an electronic spatial light modulator but not peculiar thereto using LCD's
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3161—Modulator illumination systems using laser light sources

Definitions

  • the present invention relates to the field of projection display technology, and in particular to a projection apparatus using a laser as a light source. Background technique
  • light emitted by a light source is incident on a light valve, and the light valve modulates the incident light to form image light, and the image light is projected onto a screen through an projection lens to form an image.
  • the light valve is mainly divided into three types, DMD (Digital Micro-mirror Device), liquid crystal light valve and reflective liquid crystal light valve.
  • DMD is a digital light modulator that uses a micromirror array to control the direction of reflection of incident light to form 0 and 1.
  • Each micromirror corresponds to one pixel, and each micromirror can independently control the fast flip, and the gray scale to be achieved by the pixel is controlled by controlling the number of flips to 1 in a certain period of time.
  • the principle of the liquid crystal light valve and the reflective liquid crystal light valve are close to each other, and the intensity of the emitted light is controlled to control the gray level by controlling the degree of deflection of the liquid crystal to the polarization direction of the incident polarized light.
  • the liquid crystal light valve and the reflective liquid crystal light valve Both belong to analog light modulation devices.
  • Digital Light Modulation Devices is gaining popularity among more and more people because digital modulation has many benefits that analog modulation methods cannot achieve. For example, digital light modulation has a fast response speed and the image has no tailing; for example, digital light modulation has strong anti-noise ability and the image is more realistic.
  • digital light modulation has a fast response speed and the image has no tailing; for example, digital light modulation has strong anti-noise ability and the image is more realistic.
  • DMD is monopolized by Texas Instruments and its manufacturing process is quite complex, the price of DMD has always remained high.
  • the technical problem to be solved by the present invention is to provide a low cost digital light modulation projection apparatus.
  • Embodiments of the present invention provide a projection apparatus including a laser light source and a ferroelectric liquid crystal light valve, wherein the ferroelectric liquid crystal light valve is configured to receive light emitted by the laser light source, and modulate the light according to the input image signal and emit the image light; Also included is a driving device for pulsing the laser light source such that the highest operating current when the laser source is in a lit state is higher than its rated operating current; and a synchronous control device for controlling the driving device and/or the ferroelectric liquid crystal light valve When the ferroelectric liquid crystal light valve operates in the display period, the laser light source is in a lighting state, and when the ferroelectric liquid crystal light valve operates in the reverse image period, the laser light source is in a closed state.
  • the highest operating current when the laser light source is in the lighting state is twice the rated operating current.
  • the driving device is further configured to acquire a user brightness requirement level, obtain an operating current of the laser light source corresponding to the level, and control the laser light source to operate on the acquired working current; the laser corresponding to the highest level of the user brightness requirement level
  • the operating current of the light source is the highest operating current.
  • the number of the ferroelectric liquid crystal light valves is one, and the driving device drives the laser light source to generate at least two different colors of light to form the time series light, and the time series light is incident on the ferroelectric liquid crystal light valve; the synchronous control device also uses The control driving device and/or the ferroelectric liquid crystal light valve are such that the color of the image signal modulated by the ferroelectric liquid crystal light valve is synchronized with the color of the light generated by the driving device to drive the laser light source.
  • the laser light source comprises a laser component of at least two colors, and the driving device controls the laser components of the at least two colors to form the time series lightly; or the laser light source comprises at least two laser components and at least one wavelength conversion device, at least one The laser component is incident on the at least one wavelength conversion device and generates a laser beam, and the driving device controls the at least two groups of laser components to form the time series light in time; the synchronous control device enables the corresponding operation when the ferroelectric liquid crystal light valve operates during the display period The color laser component is illuminated and the other laser components are off.
  • the laser light source comprises a laser component and a wavelength conversion wheel, the wavelength conversion wheel comprising at least two color zones, the two color zones respectively comprising two wavelength conversion materials or respectively comprising a wavelength conversion material and a scattering material,
  • the laser light emitted by the laser component is sequentially incident on at least two color regions of the wavelength conversion wheel to form time-series light; further comprising detecting means for detecting a rotational position of the wavelength conversion wheel and generating a periodic signal reflecting a rotational position of the wavelength conversion wheel;
  • the synchronous control device controls the ferroelectric liquid crystal light valve according to the periodic signal such that the color of the image signal modulated by the ferroelectric liquid crystal light valve is synchronized with the color of the light generated by the laser light source.
  • the synchronous control device controls the ferroelectric liquid crystal light valve such that when at least one of the spoke regions of the wavelength conversion wheel is on the optical path of the laser light emitted by the laser assembly, the ferroelectric liquid crystal light valve operates for at least one inverse image period.
  • the number of ferroelectric liquid crystal light valves is two or more, and the driving device drives the laser light source to generate a plurality of primary color lights of the same number as the ferroelectric liquid crystal light valves and respectively incident on the corresponding ferroelectric liquid crystal light valves and respectively modulated .
  • the laser light source comprises a white light component and a wavelength splitting device, and the white light emitted by the white light component is split by the wavelength splitting device to generate a plurality of primary colors of light having the same number as the ferroelectric liquid crystal light valve;
  • the white light component comprises a laser component and a wavelength conversion device, and the wavelength The conversion device at least partially absorbs the laser light emitted by the laser assembly and emits a laser light, and the portion of the laser light emitted by the laser or laser assembly that is not absorbed by the wavelength conversion device forms and mixes the light with the laser light to become the exit light of the white light assembly.
  • the laser light source comprises a plurality of primary color light laser components of the same number as the ferroelectric liquid crystal light valves, and the plurality of primary color lights emitted by the laser light source are respectively incident on and respectively modulated by the corresponding ferroelectric liquid crystal light valves;
  • the synchronous control device is used for Controlling at least one pair of driving devices and/or ferroelectric liquid crystal light valves, so that when the ferroelectric liquid crystal light valve operates during the display period, the laser light source is in a lighting state, and the ferroelectric liquid crystal light valve operates in an inverse image time In the segment, the laser source is off.
  • At least one primary color light laser component comprises a laser excitation source and a wavelength conversion device, and the laser excitation The source-emitting laser light is incident on the wavelength conversion device and excited to generate a received laser light, which is the primary color light emitted by the primary color light laser assembly.
  • the embodiment of the invention has the following beneficial effects:
  • the laser light source is in the lighting state and the highest operating current is higher than its rated working current, in the ferroelectric
  • the laser light source is turned off, which realizes low-cost digital light modulation by using the ferroelectric liquid crystal light valve, and also avoids the reverse image of the light of the laser light source in the ferroelectric liquid crystal light valve.
  • the time period is wasted, and at the same time, the brightness is increased due to the large operating current of the laser light source in the lighting state.
  • FIG. 1 is a schematic structural view of a first embodiment of a projection apparatus according to the present invention.
  • Figure 2a is a few examples of the operational timing of digital light modulation
  • Figure 2b is a few examples of the working sequence of the digital light modulation of the ferroelectric liquid crystal light valve
  • 3 is an example of the relationship between the outgoing light power of the laser light source and the driving current
  • FIG. 4a is a schematic structural view of a second embodiment of a projection apparatus according to the present invention.
  • 4b is a top plan view of a wavelength conversion wheel in a second embodiment of the present invention.
  • Figure 5 is a schematic structural view of a third embodiment of the projection apparatus of the present invention.
  • FIG. 6 is a schematic diagram showing the operation timing of a third embodiment of the projection apparatus of the present invention.
  • FIG. 7a is a schematic structural view of a fourth embodiment of a projection apparatus according to the present invention.
  • Figure 7b is a plan view of a wavelength conversion wheel in a fourth embodiment of the present invention.
  • Figure 8 is a timing chart showing the operation of the fourth embodiment of the projection apparatus of the present invention.
  • FIG. 9 is another schematic diagram of the operation timing of the fourth embodiment of the present invention. detailed description
  • the projection device 100 includes a laser light source 101 and a ferroelectric liquid crystal light valve 102.
  • the laser light source 101 includes three primary color light laser components 101a-101c, which respectively emit red, green, and blue laser light as primary colors, and the three primary color lights are respectively incident on the three ferroelectric liquid crystal light valves 102a-102c. They are respectively modulated by these three ferroelectric liquid crystal light valves.
  • the ferroelectric liquid crystal light valve is a kind of light valve newly developed in recent years. Although it is a kind of reflective liquid crystal light valve, it can realize digital light modulation because of its fast response to the control signal. The following digital modulation of light is explained in conjunction with Figure 2a.
  • Figure 2a shows a timing diagram of a 16-gray (0 ⁇ 15) digital light modulation.
  • the number on the left represents the desired gray level, and the horizontal line in the middle of the figure represents the state of modulation 0 or 1.
  • On the right side The number in the number is shown).
  • a specific time period is divided into four regions, which are respectively T, 2T, 4T, and 8T (as shown on the upper side of Fig. 2a).
  • Digital light modulation is the selective implementation of 0 or 1 in these four time zones, and finally the choice of 0-15 gray scale.
  • the time zone of 8 ⁇ and ⁇ is 1 and the rest is 0.
  • the rest is 0, and the time of 1 is 5 ⁇ , that is, the gray level 5 is achieved. It can be proved that by controlling the state of 0 or 1 of these four regions, all 0-15 gray scales can be realized.
  • ferroelectric liquid crystal light valves For ferroelectric liquid crystal light valves, the mechanism of digital light modulation is slightly different, see Figure 2b.
  • the ferroelectric liquid crystal light valve itself has a characteristic because of the material, that is, after the completion of the modulation to 1 or 0, in order to maintain the DC balancing at both ends of the liquid crystal light valve, the ferroelectric liquid crystal light valve must present an inverse image (inverse) Image ), working in the reverse image state, the modulation of the image cannot be performed normally.
  • the inverse image state corresponds to the same duration as the state in which it was previously modulated to 1 or 0. That is to say, the ferroelectric liquid crystal light valve always alternately operates in the display period and the reverse image period during operation.
  • each time period in which the ferroelectric liquid crystal light valve operates must still be subdivided into two sub-periods, the previous sub-period is the display period for light modulation. (Select 0 or 1), the latter sub-period is the reverse image time period and does not work properly. Therefore, even in the gray scale 15, since the light modulation is impossible for half of each time period, it is half the luminance of the digital modulation shown in Fig. 2a under the same conditions. For example, Grayscale 9, light modulation can only be performed in the first half of the 8T and T regions.
  • the projection apparatus 100 further includes a driving device 104 for respectively driving each of the primary color light laser components 101a to 101c, and a synchronization control device 103 for controlling the driving device 104 and three pieces of iron.
  • the electric liquid crystal light valves 102a to 102c are such that when at least one of the ferroelectric liquid crystal light valves (for example, the ferroelectric liquid crystal light valve 102a) operates for a display period, the corresponding primary color light laser component (for example, the red laser component 101a) is at a point. In the bright state, when the piece of ferroelectric liquid crystal light valve operates in the reverse image period, its corresponding primary color light laser component is in a closed state. In this way, the characteristics that the laser light source can be quickly switched are avoided, and the light emitted by the laser light source is prevented from being wasted when the ferroelectric liquid crystal light valve operates in the reverse image period, thereby improving the system efficiency.
  • the synchronous control device controls each pair of ferroelectric liquid crystal light valves and corresponding primary color light laser components in pairs, so that the three pairs of ferroelectric liquid crystal light valves and the primary color light laser components achieve the above work. In this way, you can maximize efficiency.
  • two ferroelectric liquid crystal light valves respectively correspond to two primary color light laser components, for example, one primary color light laser component emits white light, and the other primary color light laser component emits infrared light, and the two sets of light respectively
  • Two pieces of ferroelectric liquid crystal light valve can form a mixed image of white light and infrared light, which has special applications in many occasions (such as military training).
  • the projection device only needs to include two or more ferroelectric liquid crystal light valves and the same number of primary color light laser components, and both of them correspond to the protection range of the present embodiment.
  • the drive device 104 or the ferroelectric liquid crystal valve 102 may be separately controlled, or both may be controlled at the same time.
  • a possible control method is that the driving device 104 respectively drives the primary color laser light sources 101a to 101c to switch according to the operation mode of the aforementioned ferroelectric liquid crystal light valve, and simultaneously transmits a synchronization signal to the synchronous control device 103, and the synchronous control device 103
  • the corresponding ferroelectric liquid crystal light valve is synchronously operated (that is, when the ferroelectric liquid crystal light valve operates in the display period, the corresponding primary color light laser component is in a lighting state, and the ferroelectric liquid crystal light valve operates in the sheet.
  • the corresponding primary color light laser component is in a closed state such as a closed state, and the input light is digitally modulated according to the input image signal.
  • Another possible control method is to transmit a synchronizing signal from the ferroelectric liquid crystal shutter to the synchronizing control device 103, which controls the driving device 104 based on the synchronizing signal to drive the laser source to operate in synchronization with the ferroelectric liquid crystal shutter. It is also possible that the synchronizing signal means 103 itself generates a synchronizing signal which is sent to the driving means and the ferroelectric liquid crystal light valve respectively to synchronize the two.
  • the driving means respectively drive the laser components 101a to 101c so that the highest operating current when the latter is in the lighting state is higher than the rated operating current.
  • the laser assembly was turned off halfway, and the inventors found that the laser was not actually working at full load. This can be understood as the temperature rise of the laser assembly during the half-lighting period and the temperature drop during the half-turn period. Therefore, at this time, the laser unit can operate at a working current higher than its rated current when it is in the lighting state. With this, the highest operating current when the laser module is in the lighting state is higher than its rated operating current, and the life of the laser device is not lowered, and the luminance of the projection device can be improved.
  • Fig. 3 is an example of the relationship between the luminous power (ordinate) of the laser light source and the driving current (abscissa), and is a set of data in the actual experiment of the inventors, wherein I.
  • the rated current in general, the laser source can only work under the rated current to ensure the service life.
  • the rated current can be defined as the maximum operating current for a laser source with a service life of more than 5000 hours under continuous operation.
  • the driving current of the laser light source is still linear with the driving current when the driving current exceeds the rated current, and the curve without the saturation phenomenon is bent downward, so when the laser light source operates at a working current higher than the threshold current, At 1 2 , the efficiency will not decrease, and the heat generated will not increase. Since the laser light source is turned off for half of the time, the driving current of the laser light source in the lighting state can be twice the threshold current while keeping the service life constant.
  • the brightness of the projection device is Equivalent to the light valve using ordinary digital light modulation, the negative effects of the charge balance characteristics of the ferroelectric liquid crystal light valve are all controlled by the synchronous operation of the ferroelectric liquid crystal light valve and the laser light source and the high current drive of the laser light source. Offset.
  • the driving current of the laser light source in the lighting state is twice than the threshold current, and there is no limitation here.
  • the projection device can often adjust the brightness according to user needs. It is common practice to adjust the gray level of the light valve based on the brightness value requested by the user. For example, if the user wants to reduce the brightness by half, the light valve operates on the grayscale value of each pixel of each frame image (for example, dividing by 2, of course, considering factors such as gamma curve is not limited to direct division), The new grayscale value is displayed. Therefore, when the user adjusts to low brightness, since the light-emitting power of the light source does not change, the brightness seems to be lowered by wasting more light, and there is no corresponding saving in power.
  • the level of the brightness of the user when the brightness of the user is set to be low, the level of the brightness of the user may be directly required, and the operating current of the laser light source corresponding to the level may be acquired, and the laser light source is controlled to operate at the obtained operating current.
  • the working current of the laser light source is obtained; for example, the relationship between the brightness requirement level and the working current of the laser light source is fitted into a function, and the function is stored, and then the function is input according to the brightness requirement level to calculate the working current of the laser light source.
  • the operating current of the corresponding laser light source may be equal to or lower than its rated operating current when the user turns down the brightness, but this does not affect the beneficial effects of the embodiment. Because in the case where the user needs to use high-brightness display, the working current of the laser light source corresponding to the highest level of the user brightness requirement level is the highest working current of the laser light source, and the highest working current is higher than the rated value of the laser light source as described above. Operating current, therefore with a brighter display.
  • the primary color light laser assembly may also include a wavelength conversion device.
  • the green laser component in the above example directly emits a green laser.
  • the green laser component may include a blue laser excitation source and a green wavelength conversion device, and the blue excitation light emitted by the blue laser excitation source is incident on the green wavelength conversion device. And exciting to generate a green laser, as the green primary light emitted by the green laser assembly.
  • the wavelength conversion device may be a phosphor sheet, and includes a spectroscopic filter between the blue laser excitation source and the optical path of the phosphor sheet for reflecting the green light generated by the phosphor sheet back to the fluorescent light.
  • the powder is emitted from its opposite side.
  • the phosphor sheet may also be disposed on a reflective substrate from which blue excitation light is incident from the opposite side of the reflective substrate, and the reflective substrate reflects the green received laser light and exits from the opposite side of the reflective substrate.
  • the phosphor sheet can be fixed to a turntable and rotated, so that the excitation light is periodically incident on different positions of the excited phosphor sheet, and further The local phosphor is protected from overheating and the efficiency is reduced.
  • the selection of green here is only an example.
  • the blue or ultraviolet laser excitation source can be selected to excite the red wavelength conversion device to generate red light, which is not limited herein.
  • the red primary color light is different in polarization state before and after modulation by the ferroelectric liquid crystal light valve 102a, so that the optical paths of the two can be separated by the filter 111a, and similarly, the filter 111b and 111c is also used to separate the green primary color light and the blue primary color light by the beams before and after modulation by the ferroelectric liquid crystal light valves 102b and 102c, and the filters 111b and 111c are also used to utilize the difference in wavelengths of the modulated three primary colors. A bunch. This can be achieved using existing filter technology and will not be described here.
  • optical path forms that can realize three kinds of primary colors of light and respectively modulate into one bundle of image light (may be formed by using different wavelengths into one bundle, or can be combined into one bundle by using different spatial positions and adjacent to each other; ), here are just examples and are not limiting.
  • the combined image light can be projected onto the screen through the projection lens 112.
  • the laser light source includes a white light assembly and a wavelength splitting device 423.
  • the white light assembly includes a laser assembly 401 and a wavelength conversion device 421, and the wavelength conversion device 421 includes a motor 421b and a wavelength conversion wheel 421a.
  • a top view of the wavelength conversion wheel 421a is shown in Figure 4b, and its surface is coated with a coating of a wavelength conversion material (e.g., a phosphor coating) 421c.
  • a wavelength conversion material e.g., a phosphor coating
  • the motor 421b drives the wavelength conversion wheel 421a to rotate, so that the laser light emitted from the laser unit 401 is periodically incident on different positions of the wavelength transfer coating 421c.
  • the wavelength conversion coating 421c absorbs the laser light emitted from the laser unit 401 and emits white light by a laser light which can be used as an outgoing light of the white light component.
  • the wavelength conversion coating 421c partially absorbs the laser light emitted from the laser unit 401 and emits a laser light, and the mixed light of the laser light and the remaining portion of the laser light that is not absorbed by the wavelength conversion coating layer 421c becomes the light emitted from the white light module.
  • the laser component 401 is a blue laser component
  • the wavelength conversion coating 421c is a yellow wavelength conversion coating; the blue laser emitted by the laser component 401 excites the yellow wavelength conversion coating to generate a yellow laser, and the yellow laser and the remaining blue laser The mixture forms a white light to emit light.
  • the wavelength converting coating 421c does not necessarily comprise only one wavelength converting material, but may comprise a plurality of wavelength converting materials.
  • the function of the motor 421b is to prevent the local wavelength conversion coating from being overheated by the excitation light for a long period of time. If the heat resistance of the wavelength conversion coating is sufficiently good, or if the substrate has good heat dissipation properties, the motor 421b can be omitted.
  • the white light emitted by the white light component is split by the wavelength splitting device to generate a plurality of primary color lights (three in the present embodiment) of the same number as the ferroelectric liquid crystal light valve, and are respectively incident on the three ferroelectric liquid crystal light valves and are the latter. modulation.
  • the method for operating the ferroelectric liquid crystal light valve, the synchronous control method of the ferroelectric liquid crystal light valve and its corresponding primary color light are the same as those of the first embodiment, and the description thereof will not be repeated here.
  • the difference from the first embodiment is that the driving device 404 in this embodiment can only control the laser unit 401 without simultaneously controlling a plurality of laser units as in the first embodiment.
  • the states in which they are lit or turned off are also the same, so the display time of the corresponding three pieces of ferroelectric liquid crystal light valves in this embodiment
  • the segment and inverse image time periods are also synchronized, and are synchronized with the lighting and off states of the respective primary colors of light; this can be controlled by the synchronization control device 403, which can control the driving device 404 through only one line, and The same signal is transmitted to the three ferroelectric liquid crystal light valves through only one line.
  • the synchronization control of the three pairs of primary colors and the ferroelectric liquid crystal light valve is independent, so the control of the three pairs of primary color light and the ferroelectric liquid crystal light valve may be synchronous or different.
  • FIG. 1 A schematic structural view of a projection apparatus according to a third embodiment of the present invention is shown in FIG. The difference from the embodiment shown in FIG. 1 is that in the present embodiment, only one ferroelectric liquid crystal light valve 502 is included, and the driving device 504 drives the three laser components 501a, 501b, and 501c in the laser light source 501 to generate red, respectively. Primary light, green primary light, and blue primary light. The three primary colors of light are combined by the wavelength combining device 523 and incident on the ferroelectric liquid crystal light valve 502, and the modulated light is emitted from the ferroelectric liquid crystal light valve 502 and projected onto the screen by the projection lens.
  • the input image signal is decomposed into red, green and blue primary color images and then read by three ferroelectric liquid crystal light valves and used to modulate the incident three primary color primary colors and generate corresponding three primary color images.
  • the laser light source generates time-series light of the primary color light in a time-sharing manner, that is, periodically generates red, green, and blue primary light, and the periodic basis of the ferroelectric liquid crystal light valve is synchronized with it.
  • the image signal modulates the red, green, and blue primary colors to obtain time-series image light of the three primary color images. As long as the switching speed of the three primary color image lights is fast enough (for example, higher than 50 Hz), the human eye cannot distinguish the primary color images, and the human eye sees the color images generated by superimposing the respective primary color images.
  • the driving device controls the laser components 501a-501c of the three colors in a time-sharing manner so that the laser light source 501 generates three different colors of light to form time-series light, and the ferroelectric liquid crystal light valve 502 is time-divisionally modulated.
  • the three primary colors of light, the timing of their modulation and the corresponding lighting sequence of the primary color laser components are shown in Figure 6.
  • the areas covered by “red”, “green” and “blue” in the upper part of Fig. 6 represent the time ranges of generation and modulation of the three primary colors of light, respectively.
  • the red image is first modulated, and the ferroelectric liquid crystal light valve 502 is modulated according to the read red image signal, and the modulation method is the same as that of the first and second embodiments; in this embodiment, the red gray scale is 15 (Highest gray scale), at this time, the synchronous control device 503 controls the driving device 504 to drive the red laser light assembly 501a to generate red primary color light incident on the ferroelectric liquid crystal light valve 502, and the laser components 501b and 501c of other colors are in a closed state. Then, the green image is modulated, and the ferroelectric liquid crystal light valve 502 is modulated according to the read green image signal.
  • the green gray scale is 5, so the display period of the first half in the 8T and 2T periods is modulated to 0. (Although the modulation is 0, the primary color light corresponding to the display period still needs to be lit), at this time, the synchronization control device 503 controls the driving device 504 to drive the green laser component 501b to generate green primary color light incident on the ferroelectric liquid crystal light valve 502, and the like.
  • the color laser components 501a and 501c are in a closed state.
  • the blue image is modulated, and the ferroelectric liquid crystal light valve 502 modulates according to the read blue image signal.
  • the blue gray scale is 0, so the display period of the first half of all time periods is modulated.
  • the synchronization control device 503 controls the driving device 504 to drive the blue laser component 501c to generate blue primary color light incident on the ferroelectric Liquid crystal light valve 502, other
  • the color laser components 501a and 501b are in a closed state.
  • the order of red, green and blue and the duration of each color modulation can be preset and controlled, as long as the synchronization control device 503 controls the driving device 504 and the ferroelectric liquid crystal light valve 502 such that the ferroelectric liquid crystal light valve 502
  • the color of the modulated image signal may be synchronized with the color of the light generated by the driving device 504 driving the laser light source.
  • the synchronizing control means that when the ferroelectric liquid crystal light valve 502 is operated for the display period, only the laser components of the corresponding colors are in the lighting state and the other laser components are in the off state.
  • the synchronization control device 503 can control only the driving device 504 or the ferroelectric liquid crystal light valve 502, or both, depending on whether the synchronization signal is generated from a ferroelectric liquid crystal light valve or The driving device or the synchronous control device itself; this part has been fully explained in the first embodiment and will not be repeated here.
  • the laser source may also include the use of a laser assembly to emit laser light to excite a wavelength conversion device to produce primary color light, e.g., using a blue laser to excite a green wavelength conversion device to produce green primary color light.
  • a green laser component that does not affect the generation and synchronization of timing light.
  • the three primary colors of light are incident on the ferroelectric liquid crystal light valve 502 after being combined by the wavelength combining device 523, and are modulated by the same; in practical applications, the three primary colors of light can be different from each other.
  • the angle is incident on the ferroelectric liquid crystal light valve 502, and the wavelength combining device 523 is not required at this time.
  • the laser light source includes a laser unit 701 and a wavelength conversion wheel 721.
  • the wavelength conversion wheel includes at least two color regions.
  • the wavelength conversion wheel 721 specifically includes three color regions, as shown in Fig. 7b.
  • Figure 7b is a top plan view of the wavelength conversion wheel 721.
  • the three color regions 721a, 721b, and 721c are a red wavelength conversion material coating, a green wavelength conversion material coating, and a blue wavelength conversion material coating, respectively, and the laser assembly 701 emits an ultraviolet laser.
  • the ultraviolet laser is periodically incident on the three color regions 721a to 721c and generates a red, green and blue received laser light, and the red, green and blue light is converted into time series light and incident on the ferroelectric liquid crystal.
  • the light valve 702 is time-divisionally modulated.
  • the laser component 701 may also emit a primary color light, such as blue light, at which point the blue wavelength converting material layer on the wavelength converting wheel is replaced with a scattering material coating.
  • a scattering material coating is used to scatter the blue laser light, which effectively prevents speckle from appearing on the projection screen.
  • a detecting device 722 is further included for detecting the rotational position of the wavelength conversion wheel and generating a periodic signal reflecting the rotational position of the wavelength conversion wheel.
  • Fig. 8 shows an operation timing chart of the present embodiment, and an example of the periodic signal is shown as the first broken line in the horizontal direction in Fig. 8 (as indicated on the left side in the figure). It can be seen that in the present embodiment, the wavelength conversion wheel 721 rotates one cycle to sequentially generate red, green and blue primary light, and a positive pulse is generated by the detecting means 722 at the beginning of each period of red light. The pulse is a periodic signal, which can mark the rotational position of the wavelength conversion wheel, and calculate the red primary color and the green primary color accordingly.
  • the synchronization control means 703 can control the ferroelectric liquid crystal light valve 702 in accordance with the periodic signal so that the color of the image signal modulated by the ferroelectric liquid crystal light valve is synchronized with the color of the light generated by the wavelength conversion wheel.
  • the synchronization control device 703 also needs to control the laser assembly 701 to synchronize with the ferroelectric liquid crystal light valve 702 to realize that the ferroelectric liquid crystal light valve 702 is in the display period, the laser assembly 701 is in the lighting state, and the ferroelectric liquid crystal shutter 702 is in the illumination state. When operating in the reverse image period, the laser assembly 701 is in the off state.
  • spoke area the area covered by the excitation light spot on both sides of the intersection of different color areas
  • spoke time period the time period corresponding to the spoke area
  • spoke light the light emitted by the spoke area
  • FIG. 8 shows a more preferred working timing diagram in which the vertical shaded areas represent spoke time periods.
  • the display time period of the ferroelectric liquid crystal light valve is shifted, and the order of the time period of 1 ⁇ 2T, 4 ⁇ , 8 ⁇ is adjusted, so that the spoke time period is shifted from the display time period, and the spoke time period corresponds to the ferroelectric liquid crystal light valve.
  • Part of the inverse image time period which of course increases efficiency.

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Abstract

一种投影装置（100），包括激光光源（101）、铁电液晶光阀（102）、驱动装置（104）以及同步控制装置（103）。铁电液晶光阀（102）用于接收激光光源（101）发出的光，并根据输入图像信号对该光进行调制并出射图像光。驱动装置（104）用于脉冲驱动激光光源（101），使得激光光源（101）处于点亮状态时的最高工作电流高于其额定工作电流。同步控制装置（103）用于控制驱动装置（104）和/或铁电液晶光阀（102），使得在铁电液晶光阀（102）工作于显示时间段时，激光光源（101）处于点亮状态，在铁电液晶光阀（102）工作于反图像时间段时，激光光源（101）处于关闭装置。该投影装置（100）既利用铁电液晶光阀（102）实现了低成本的数字光调制，也避免了激光光源（101）的光在铁电液晶光阀（102）的反图像时间段的浪费，同时由于激光光源（101）在点亮状态时工作电流较大而提升了投影装置（100）的亮度。

Description

投影装置
技术领域
本发明涉及投影显示技术领域，特别是涉及一种使用激光作为光源的投影装置。 背景技术
投影显示技术中， 光源发出的光入射于光阀， 光阀调制该入射光形成图像光， 该图像光经过投影透镜投射到屏幕上形成图像。
目前，光阀主要分为三种，德州仪器公司的 DMD ( Digital Micro-mirror Device )、 液晶光阀和反射式液晶光阀。 DMD是一种数字光调制器，它利用一个微镜阵列控制 入射光的反射方向形成 0和 1。 每一个微镜对应于一个像素， 每一个微镜都可以独 立控制快速翻转， 通过在一个特定时间段内控制翻转至 1的次数来控制该像素所要 实现的灰阶。 液晶光阀和反射式液晶光阀的原理接近， 都是通过控制液晶对于入射 偏振光的偏振方向的偏转程度来控制出射光的强度以实现其灰阶的， 液晶光阀和反 射式液晶光阀都属于模拟光调制器件。
数字光调制器件 DMD正在被越来越多的人所喜爱， 原因在于数字调制方式有 很多模拟调制方式所不能实现的好处。 例如数字光调制的响应速度快， 图像无拖尾； 又例如数字光调制的抗噪能力强， 图像更逼真。 然而， 由于 DMD被德州仪器公司 所垄断， 且其制造工艺相当复杂， DMD的售价始终居高不下。
因此人们在选择光阀时面临两难选择， 该问题至今没有解决。 发明内容
本发明主要解决的技术问题是提供一种低成本的数字光调制的投影装置。
本发明实施例提供了一种投影装置， 包括激光光源和铁电液晶光阀， 铁电液晶 光阀用于接收激光光源发出的光， 并根据输入图像信号对该光进行调制并出射图像 光； 还包括驱动装置， 用于脉冲驱动激光光源， 使得激光光源处于点亮状态时的最 高工作电流高于其额定工作电流； 还包括同步控制装置， 用于控制驱动装置和 /或铁 电液晶光阀， 使得在铁电液晶光阀工作于显示时间段时， 激光光源处于点亮状态， 在铁电液晶光阀工作于反图像时间段时， 激光光源处于关闭状态。
优选的， 激光光源处于点亮状态时的最高工作电流为额定工作电流的二倍。 优选的， 驱动装置还用于获取用户亮度要求等级， 并获取与该等级对应的激光 光源的工作电流， 并控制激光光源工作于该获取的工作电流； 用户亮度要求等级的 最高等级所对应的激光光源的工作电流是最高工作电流。 优选的， 铁电液晶光阀的数量是一片， 驱动装置驱动激光光源分时产生至少两 种不同颜色的光构成时序光， 并使该时序光入射于铁电液晶光阀； 同步控制装置还 用于控制驱动装置和 /或铁电液晶光阀， 使得铁电液晶光阀所调制的图像信号的颜 色， 与驱动装置驱动激光光源所产生的光的颜色保持同步。
优选的， 激光光源包括至少两种颜色的激光组件， 驱动装置分时控制该至少两 种颜色的激光组件形成时序光； 或者， 激光光源包括至少两个激光组件和至少一个 波长转换装置，至少一个激光组件入射于至少一个波长转换装置并使其产生受激光， 驱动装置分时控制至少两组激光组件形成时序光； 同步控制装置使得在铁电液晶光 阀工作于显示时间段时， 相对应的颜色的激光组件处于点亮状态而其它激光组件处 于关闭状态。
优选的， 激光光源包括一个激光组件和一个波长转换轮， 该波长转换轮包括至 少两个颜色区， 该两个颜色区分别包括两种波长转换材料或者分别包括一种波长转 换材料和散射材料， 激光组件发出的激光依次入射于波长转换轮的至少两个颜色区 形成时序光； 还包括探测装置， 用于探测波长转换轮的转动位置， 并产生反映波长 转换轮的转动位置的周期性信号； 同步控制装置根据周期性信号控制铁电液晶光阀 使得铁电液晶光阀所调制的图像信号的颜色与激光光源所产生的光的颜色保持同 步。
优选的， 同步控制装置控制铁电液晶光阀， 使得当波长转换轮的至少一个轮辐 区处于激光组件发射的激光的光路上时， 铁电液晶光阀工作于至少一个反图像时间 段。
优选的， 铁电液晶光阀的数量是两片或以上， 驱动装置驱动激光光源产生与铁 电液晶光阀数量相同的若干个基色光并分别入射于对应的铁电液晶光阀并被分别调 制。
优选的， 激光光源包括白光组件和波长分光装置， 该白光组件发出的白光经过 波长分光装置分光产生与铁电液晶光阀数量相同的若干个基色光； 白光组件包括激 光组件和波长转换装置， 波长转换装置至少部分吸收激光组件发出的激光并发射受 激光， 该受激光或者激光组件发射的激光中没有被波长转换装置吸收的部分与该受 激光形成和混合光成为该白光组件的出射光。
优选的， 激光光源包括与铁电液晶光阀数量相同的若干个基色光激光组件， 它 们发射的若干束基色光分别入射于对应的铁电液晶光阀并被其分别调制； 同步控制 装置用于控制相对应的至少一对驱动装置和 /或铁电液晶光阀， 使得在铁电液晶光阀 工作于显示时间段时， 激光光源处于点亮状态， 在铁电液晶光阀工作于反图像时间 段时， 激光光源处于关闭状态。
优选的， 至少一个基色光激光组件包括激光激发源和波长转换装置， 激光激发 源发射的激光入射于波长转换装置并激发产生受激光， 该受激光是该基色光激光组 件发射的基色光。
与现有技术相比， 本发明实施例具有如下有益效果：
结合激光光源和铁电液晶光阀， 并控制两者同步工作使得在铁电液晶光阀工作 于显示时间段时， 激光光源处于点亮状态且最高工作电流高于其额定工作电流， 在 铁电液晶光阀工作于反图像时间段时， 激光光源处于关闭状态， 这样既利用铁电液 晶光阀实现了低成本的数字光调制， 也避免了激光光源的光在铁电液晶光阀的反图 像时间段的浪费， 同时由于激光光源在点亮状态时工作电流较大而提升了亮度。 附图说明
图 1为本发明投影装置的第一实施例的结构示意图；
图 2a为数字光调制的工作时序的几个举例；
图 2b为铁电液晶光阀数字光调制的工作时序的几个举例;
图 3为激光光源的出射光功率与驱动电流的关系举例；
图 4a为本发明投影装置的第二实施例的结构示意图；
图 4b为本发明第二实施例中波长转换轮的俯视图；
图 5为本发明投影装置的第三实施例的结构示意图；
图 6为本发明投影装置的第三实施例的工作时序示意图；
图 7a为本发明投影装置的第四实施例的结构示意图；
图 7b为本发明的第四实施例中波长转换轮的俯视图；
图 8为本发明投影装置的第四实施例的工作时序示意图；
图 9为本发明第四实施例的另一种工作时序示意图。 具体实施方式
下面结合附图及实施方式来对本发明的实施例进行详细分析。
本发明的投影装置的第一实施例的结构示意图如图 1所示。 投影装置 100包括 激光光源 101和铁电液晶光阀 102。 其中， 激光光源 101 包括三个基色光激光组件 101a~101c, 它们分别发射红色、 绿色和蓝色的激光作为基色光， 这三束基色光分别 入射于三片铁电液晶光阀 102a~102c, 并分别被这三片铁电液晶光阀调制。
铁电液晶光阀是近年来新发展起来的一种光阀， 它虽然属于反射式液晶光阀的 一种， 但是由于其对控制信号的响应速度很快因此可以实现数字式的光调制。 以下 对数字式的光调制， 结合图 2a进行解释。
图 2a所示的是一个 16灰阶（0~15 ) 的数字光调制的时序图， 左边的数字代表 希望实现的灰阶， 图中间水平方向的折线代表调制的 0或 1的状态 （如图右侧在括 号中的数字所示）。 将一个特定的时间段分为四个区域， 其时间分别为 T, 2T, 4T, 8T (如图 2a上侧所示的）。 其中 T是一个单位时间， 也代表一个灰阶的亮度， 这样 最亮的状态就是所有区域都为 1 , 此时为 1的时间为 T+2T+4T+8T=15T, 即灰阶为 15； 同时最暗的状态就是所有区域都为 0, 此时为 1的时间是 0, 即灰阶为 0。 数字 式的光调制就是在这四个时间区域内选择性的实现 0或 1 , 最终实现 0~15灰阶的选 择。
例如对于灰阶 9, 则 8Τ和 Τ的时间区域为 1 , 其余为 0, 此时为 1 的时间是 Τ+8Τ=9Τ, 即实现了灰阶 9; 又例如 4Τ和 Τ的区域为 1 , 其余为 0, 此时为 1的时 间是 5Τ, 即实现了灰阶 5。 可以证明， 分别控制这四个区域的 0或 1的状态， 可以 实现所有的 0~15灰阶。 值得一提的是， 此处的 16灰阶需要将特定的时间段分为 4 个区， 这是因为 16=24； 可以证明， 要实现 2η的灰阶显示， 只要将特定的时间段分 为 η份即可。 因此本实施例中以及下面实施例中使用的 16灰阶仅是举例， 并不限制 实际中对其它灰阶数 (例如 256灰阶） 的使用。
对于铁电液晶光阀来说， 其数字光调制的机制又略有不同， 参考图 2b。 铁电液 晶光阀本身由于材料的原因具有一个特点， 就是在调制成 1或 0完成后， 为了保持 液晶光阀两端的电荷平衡（DC balancing ) , 铁电液晶光阀必须呈现一个反图像 ( inverse image ), 工作于反图像状态， 此时图像的调制无法正常进行。 反图像状态 所对应的时长与其前面调制成 1或 0的状态的时长相同。 也就是说， 铁电液晶光阀 在工作中总是交替的工作于显示时间段和反图像时间段。
因此， 如图 2b所示， 与图 2a的情况不同， 铁电液晶光阀工作的每个时间段仍 然必须再分为前后两个子时间段， 前面的子时间段为显示时间段用于光调制 （选择 0或 1 ), 后一个子时间段为反图像时间段， 不能正常工作。 因此即使是灰阶 15 , 由 于每个时间段都有一半的时间无法进行光调制，在其它条件相同的条件下比图 2a所 示的数字式调制亮度低一半。 例如灰阶 9, 只能在 8T和 T区域中的前一半时间进行 光调制。
在本实施例中， 投影装置 100还包括驱动装置 104, 该驱动装置 104用于分别 脉冲驱动各基色光激光组件 101a~101c; 还包括同步控制装置 103 , 用于控制驱动装 置 104和三片铁电液晶光阀 102a~102c, 使得在至少一片铁电液晶光阀 （例如铁电 液晶光阀 102a )工作于显示时间段时， 其对应的基色光激光组件（例如红光激光组 件 101a )处于点亮状态， 在该片铁电液晶光阀工作于反图像时间段时， 其对应的基 色光激光组件处于关闭状态。 这样， 利用了激光光源可以快速开关的特点， 避免了 激光光源发出的光在铁电液晶光阀工作于反图像时间段时被浪费，提高了***效率。
可以理解， 优选的情况是， 同步控制装置成对的控制每一对铁电液晶光阀和对 应的基色光激光组件， 使得三对铁电液晶光阀和基色光激光组件都实现上述的工作 方式， 这样可以达到效率的最大化。 在实际应用中， 也可能是两个铁电液晶光阀分 别对应于两个基色光激光组件， 例如一个基色光激光组件发射白光， 另一个基色光 激光组件发射红外光， 这两组光分别经两片铁电液晶光阀调制后可以形成白光和红 外光的混合图像， 这在很多场合（如军事训练）有特殊的应用。 筒而言之， 该投影 装置只要包括两片或以上铁电液晶光阀和与之相同数量的基色光激光组件， 且两者 ——对应， 就属于本实施例的保护范围。
在同步控制装置 103的具体工作过程中， 可能单独控制驱动装置 104或铁电液 晶光阀 102, 也可能同时控制二者。 例如， 一种可能的控制方法是， 驱动装置 104 分别驱动基色光激光光源 101a~101c按照前述的铁电液晶光阀的工作方式开关， 同 时发送同步信号至同步控制装置 103 , 同步控制装置 103才艮据该同步信号控制相应 的铁电液晶光阀同步工作 （即铁电液晶光阀工作于显示时间段时， 其对应的基色光 激光组件处于点亮状态， 在该片铁电液晶光阀工作于反图像时间段时， 其对应的基 色光激光组件处于关闭状态这样的同步方式），并根据输入图像信号对输入光进行数 字式光调制。
另一种可能的控制方法是， 由铁电液晶光阀发送同步信号至同步控制装置 103 , 后者根据该同步信号控制驱动装置 104, 使其驱动激光光源与铁电液晶光阀同步工 作。 还有一种可能是同步信号装置 103 自身生成一个同步信号， 分别发送至驱动装 置和铁电液晶光阀使二者同步工作。
在本实施例中， 驱动装置分别驱动激光组件 101a~101c, 使得后者处于点亮状 态时的最高工作电流高于其额定工作电流。 才艮据上面的描述， 激光组件有一半的时 间处于关闭状态， 发明人发现此时激光实际上并不是工作在满负荷的状态。 这可以 理解为， 在点亮的一半时间激光组件的温度上升， 而在关闭的一半时间其温度则得 以下降。 因此， 此时激光组件在点亮状态时是可以工作于高于其额定电流的工作电 流的。 利用这一点， 本实施例使激光组件处于点亮状态时的最高工作电流高于其额 定工作电流， 并不会降低其使用寿命， 而且可以提高投影装置的发光亮度。
图 3是激光光源的发光功率 （纵坐标） 与驱动电流（横坐标）之间的关系的举 例， 是发明人的实际实验中的一组数据， 其中 I。为阈值电流， 为额定电流， 一般 情况下该激光光源只能工作于额定电流之下才能保证使用寿命。 额定电流可以定义 为， 连续工作下激光光源使用寿命超过 5000小时前提下的最大工作电流。
由图 3可以看出， 激光光源的驱动电流在超过额定电流时其发光强度仍然与驱 动电流保持线性关系而没有出现饱和现象的曲线下弯， 因此当激光光源工作于高于 阈值电流 的工作电流 12时， 其效率并不会下降， 产生的热量并不会增大。 由于激 光光源有一半时间处于关闭状态， 因此在保持使用寿命不变的前提下， 激光光源处 于点亮状态下的驱动电流最大可以为阈值电流的二倍。 此时投影装置的发光亮度就 等同于使用了普通的数字式光调制的光阀， 铁电液晶光阀的电荷平衡特性所带来的 负面影响全部通过控制铁电液晶光阀与激光光源的同步工作以及激光光源的高电流 驱动所抵消。 当然在有些对于使用寿命要求不高的场合， 激光光源处于点亮状态下 的驱动电流高于阈值电流的二倍也是可能的， 此处并不做限制。
在实际应用中， 投影装置往往可以根据用户需求调整亮度。 通常的做法是， 根 据用户要求的亮度数值改变光阀的灰阶来实现调整。例如用户希望把亮度降低一半， 则光阀对于每一帧图像的每一个像素的灰阶值进行运算（例如除以 2 , 当然考虑到 伽马曲线等因素并不限于直接进行除法运算），得到新的灰阶值后再进行显示。因此， 在用户调整为低亮度时， 由于光源的发光功率并没有变， 因此只是通过浪费更多的 光来使亮度看起来变低， 电能并没有相应的节省。
在本发明的实施例中， 当用户设置亮度变低时， 可以直接按照用户的亮度要求 等级， 并获取与该等级对应的激光光源的工作电流， 并控制激光光源工作于该获取 的工作电流。 这样在用户调低亮度的时候可以实现省电的效果。 根据用户的亮度要 求等级获取激光光源工作电流的方法有很多， 例如实现将亮度要求等级与激光光源 工作电流制作成一个数据表并存储于驱动装置内的存储器内， 根据亮度要求等级查 表就可以得到激光光源工作电流； 又例如将亮度要求等级与激光光源工作电流的关 系拟合成函数， 并将该函数储存， 再根据亮度要求等级带入该函数进行计算得到激 光光源的工作电流。
可以理解， 当用户将亮度调低后相应的激光光源的工作电流可能等于甚至低于 其额定工作电流， 但这并不影响本实施例的有益效果。 因为在用户需要使用高亮度 显示的情况下， 用户亮度要求等级的最高等级所对应的激光光源的工作电流就是激 光光源的最高工作电流，如前所述的该最高工作电流高于激光光源的额定工作电流， 因此具有更亮的显示效果。
在本实施例中， 基色光激光组件还可能包括波长转换装置。 例如， 在上面例子 中的绿色激光组件直接发射绿色激光， 实际上绿色激光组件可以包括蓝色激光激发 源和绿色波长转换装置， 蓝色激光激发源发射的蓝色激发光入射于绿色波长转换装 置并激发产生绿色受激光， 作为该绿色激光组件发射的绿色基色光。
实际中， 波长转换装置可能是一个荧光粉片， 在蓝色激光激发源和荧光粉片的 光路之间还包括一个分光滤光片， 用于将荧光粉片受激产生的绿光反射回荧光粉片 并从其异侧发射。 荧光粉片还可能设置与一个反射衬底上， 蓝色激发光从反射衬底 的异侧入射， 反射衬底反射绿色受激光并使其从反射衬底的异侧出射。 考虑到荧光 粉受激时本身会发热， 为了降低发热的影响， 可以将荧光粉片固定于一个转盘并使 其转动， 这样激发光就会周期性的入射于激发荧光粉片的不同位置， 进而使局部荧 光粉免于过热造成的效率下降。 可以理解， 此处选择绿色只是一个举例， 当然也可以同理的选择蓝色或紫外激 光激发源来激发红色波长转换装置来产生红光， 此处并不做限制。
在图 1所示的实施例中，红色基色光被铁电液晶光阀 102a调制前后的偏振态不 同， 因此可以通过滤光片 111a来将二者的光路分开， 同样道理，滤光片 111b和 111c 也用来将绿色基色光和蓝色基色光被铁电液晶光阀 102b和 102c调制前后的光束分 开， 同时滤光片 111b和 111c还用来将调制后的三基色光利用波长的差异而合为一 束。 这使用现有的滤光片技术就可以实现， 此处不赘述。 实际上， 存在多种光路形 式可以实现三种基色光分别调制后合为一束图像光（可以是利用波长不同合为一束， 也可以使利用空间位置不同而相互毗邻的合为一束；)， 此处只是举例而并不作限制。 该合为一束的图像光经过投影镜头 112可以投射至屏幕上。
本发明的第二实施例如图 4a所示。本实施例与第一实施例的区别在于激光光源 的组成和控制方法不同。 在本实施例中， 激光光源包括白光组件和波长分光装置 423。 白光组件包括激光组件 401和波长转换装置 421 , 波长转换装置 421包括马达 421b和波长转换轮 421a。 波长转换轮 421a的俯视图如图 4b所示， 其表面涂覆有波 长转换材料涂层（如荧光粉涂层） 421 c。 马达 421b驱动波长转换轮 421a转动， 使 得激光组件 401发出的激光周期性的入射于波长转涂层 421c的不同位置。波长转换 涂层 421c吸收激光组件 401发出的激光并发射白光受激光，该白光受激光可以作为 白光组件的出射光。
或者波长转换涂层 421c部分吸收激光组件 401发出的激光并发射受激光，该受 激光与没有被波长转换涂层 421c吸收的剩余部分激光的混合光成为该白光组件的 出射光。 例如激光组件 401为蓝光激光组件， 波长转换涂层 421c为黄色波长转换涂 层； 激光组件 401发出的蓝色激光激发黄色波长转换涂层产生黄色受激光， 该黄色 受激光与剩余的蓝色激光混合形成白光出射光。 可以理解， 波长转换涂层 421c不一 定只包含一种波长转换材料， 而可能包含多种波长转换材料。
在本实施例中，马达 421b的作用在于避免局部波长转换涂层被激发光长期激发 而过热。 若波长转换涂层的耐热性能足够好， 或者其衬底具有良好的散热性能， 则 马达 421b可以省略。
白光组件发出的白光经过波长分光装置分光产生与铁电液晶光阀数量相同的若 干个基色光（在本实施例中为 3个），并分别入射于三片铁电液晶光阀并被后者调制。
在本实施例中， 铁电液晶光阀的工作方法、 铁电液晶光阀与其对应的基色光的 同步控制方法与第一实施例相同， 此处不做重复描述。 与第一实施例不同之处在于， 本实施例中的驱动装置 404只能控制激光组件 401 , 而不像第一实施例那样同时控 制多个激光组件。 由于各基色光是通过波长分光装置 423同时产生的， 其处于点亮 或关闭的状态也是相同的， 因此在本实施例中相应的三片铁电液晶光阀的显示时间 段和反图像时间段也是同步的， 且都与各基色光的点亮和关闭状态同步； 这可以通 过同步控制装置 403来控制实现， 同步控制装置 403可以只通过一条线路控制驱动 装置 404, 并只通过一条线路传送相同的信号给三片铁电液晶光阀。 与之不同的， 第一实施例中， 三对基色光与铁电液晶光阀的同步控制是独立的， 所以三对基色光 与铁电液晶光阀的控制可以是同步的， 也可以不同。
本发明的第三实施例的投影装置的结构示意图如图 5所示。 与图 1所示的实施 例的不同之处在于， 在本实施例中只包括一片铁电液晶光阀 502, 驱动装置 504分 别驱动激光光源 501中的三个激光组件 501a、 501b和 501c产生红色基色光、 绿色 基色光和蓝色基色光。 三种基色光经过波长合光装置 523合光后入射于铁电液晶光 阀 502并被其调制，调制后的光从铁电液晶光阀 502出射后被投影镜头投射至屏幕。
我们知道， 彩色图像往往是由红绿蓝三基色图像叠加而成。 在第一和第二实施 例中， 输入图像信号被分解为红绿蓝三基色图像后分别被三片铁电液晶光阀读取并 用来调制入射的三基色基色光并产生相应的三基色图像。 在本实施例和下一个实施 例中， 激光光源分时的产生基色光的时序光， 即周期性的轮流产生红绿蓝三基色光， 铁电液晶光阀则与之同步的周期性的根据图像信号调制红绿蓝三基色光来得到三基 色图像的时序图像光。 只要三基色图像光的切换速度足够快（例如高于 50赫兹）， 人眼就无法分辨各基色图像， 人眼看到的是将各基色图像叠加而产生的彩色图像。
具体而言在本实施例中， 驱动装置分时控制三种颜色的激光组件 501a~501c使 得激光光源 501分时产生三种不同颜色的光构成时序光， 铁电液晶光阀 502分时的 调制三种基色光， 其调制工作时序和相应的基色光激光组件的点亮工作时序如图 6 所示。 图 6上部的 "红" "绿" "蓝" 所覆盖的区域分别表示三种基色光的产生和调 制的时间范围。 如图所示， 首先调制红色图像， 此时铁电液晶光阀 502根据读取的 红色图像信号进行调制， 调制方法与第一和第二实施例相同； 在本实施例中红色灰 阶为 15 (最高灰阶）， 此时同步控制装置 503控制驱动装置 504驱动红色激光组件 501a产生红色基色光入射于铁电液晶光阀 502, 其它颜色的激光组件 501b和 501c 处于关闭状态。 接着调制绿色图像， 铁电液晶光阀 502根据读取的绿色图像信号进 行调制， 在本实施例中绿色灰阶为 5 , 因此在 8T和 2T时间段中的前一半的显示时 间段调制为 0 (虽然调制为 0但在显示时间段相对应的基色光仍然需要点亮）， 此时 同步控制装置 503控制驱动装置 504驱动绿色激光组件 501b产生绿色基色光入射于 铁电液晶光阀 502, 其它颜色的激光组件 501a和 501c处于关闭状态。 接着调制蓝 色图像， 铁电液晶光阀 502根据读取的蓝色图像信号进行调制， 在本实施例中蓝色 灰阶为 0, 因此在所有时间段中的前一半的显示时间段均调制为 0 (虽然调制为 0 但在调制时间段相对应的蓝色基色光仍然需要点亮），此时同步控制装置 503控制驱 动装置 504驱动蓝色激光组件 501c产生蓝色基色光入射于铁电液晶光阀 502, 其它 颜色的激光组件 501a和 501b处于关闭状态。
在实际应用中， 红绿蓝的顺序以及每个颜色调制的时长是可以预先设置和控制 的， 只要同步控制装置 503控制驱动装置 504和铁电液晶光阀 502 , 使得铁电液晶 光阀 502所调制的图像信号的颜色， 与驱动装置 504驱动激光光源所产生的光的颜 色保持同步即可。 这意味着在本实施例中， 同步控制装置使得在铁电液晶光阀 502 工作于显示时间段时， 只有相对应的颜色的激光组件处于点亮状态而其它激光组件 处于关闭状态。 与第一实施例类似的， 同步控制装置 503可以只控制驱动装置 504 或铁电液晶光阀 502, 或者同时控制二者， 这取决于同步信号的产生来源是来自于 铁电液晶光阀或是驱动装置或是同步控制装置自身； 这部分内容已经在第一实施例 充分说明， 此处不再重复。
在实际应用中， 与第一实施例类似的， 激光光源也可以包括使用激光组件发射 激光来激发波长转换装置来产生基色光， 例如使用蓝光激光激发绿色波长转换装置 来产生绿色基色光。 这只是绿光激光组件的另一种实现方式， 并不影响时序光的产 生及同步控制。
值得注意的是， 在本实施例中， 三种基色光经过波长合光装置 523合光后入射 于铁电液晶光阀 502并被其调制； 在实际应用中三种基色光可以分别从不同的角度 入射于铁电液晶光阀 502, 此时就不需要波长合光装置 523。
本发明的第四实施例的投影装置的结构示意图如图 7a所示。与第三实施例不同 的是， 在本实施例中， 激光光源包括一个激光组件 701和一个波长转换轮 721。 该 波长转换轮包括至少两个颜色区， 在本实施例中该波长转换轮 721具体的包括三个 颜色区， 如图 7b所示。 图 7b是波长转换轮 721的俯视图， 三个颜色区 721a、 721b 和 721c分别为红色波长转换材料涂层、绿色波长转换材料涂层和蓝色波长转换材料 涂层， 而激光组件 701发射紫外激光， 随着波长转换轮 721的转动， 该紫外激光周 期性的依次入射于三个颜色区 721a~721c并产生红绿蓝受激光， 该红绿蓝受激光成 为时序光， 并入射于铁电液晶光阀 702被其分时调制。
在实际应用中， 激光组件 701也可能发射一种基色光， 例如蓝光， 此时波长转 换轮上的蓝色波长转换材料层被替换为散射材料涂层。 散射材料涂层用于将蓝光激 光散射， 这样可以有效的避免在投影屏幕上出现散斑。
在本实施例中， 还包括探测装置 722, 用于探测波长转换轮的转动位置， 并产 生反映波长转换轮的转动位置的周期性信号。 图 8显示了本实施例的工作时序图， 周期性信号的一个实例显示为图 8中的水平方向的第一条折线 （如图中左侧所标出 的）。 可见在本实施例中， 波长转换轮 721转动一个周期依次产生红绿蓝三基色光， 并在每个周期的红光刚开始时由探测装置 722产生一个正脉冲。 该脉冲就是周期性 信号， 它可以标志出波长转换轮的转动位置， 并依此计算出红色基色光、 绿色基色 光和蓝色基色光的时序和时长。 这样， 同步控制装置 703就可以根据周期性信号控 制铁电液晶光阀 702使得铁电液晶光阀所调制的图像信号的颜色与波长转换轮所产 生的光的颜色保持同步。
同步控制装置 703还需要控制激光组件 701与铁电液晶光阀 702进行同步， 以 实现铁电液晶光阀 702工作于显示时间段时， 激光组件 701处于点亮状态， 在铁电 液晶光阀 702工作于反图像时间段时， 激光组件 701处于关闭状态。
在本实施例中， 当波长转换轮 721上不同颜色区的交界处通过激发光的入射光 斑时， 出射光是混色的， 该混色的光并不能被当作基色光来使用。 不同颜色区的交 界处两侧覆盖激发光光斑的区域称为 "轮辐区"， 轮辐区对应的时间段称为 "轮辐时 间段"， 轮辐区发射的光称为 "轮辐光"。
在图 8所示的工作时序中，轮辐时间段与铁电液晶光阀的部分显示时间段重合， 如上所述由于轮辐光不能被有效使用从而造成了效率损失。 图 9显示了一种更为优 选的工作时序图， 图中的纵向的阴影区代表轮辐时间段。 图中， 铁电液晶光阀的显 示时间段平移， 且1\ 2T、 4Τ、 8Τ时间段的顺序做了调整， 使得轮辐时间段与显示 时间段错开， 轮辐时间段对应于铁电液晶光阀的反图像时间段的一部分， 这样当然 就提高了效率。 推而广之， 只要当波长转换轮的至少一个轮辐区处于激光组件发射 的激光的光路上时， 铁电液晶光阀工作于至少一个反图像时间段， 就可以实现效率 的提高。 当然， 各基色光的控制时序也要与铁电液晶光阀同步的进行调整。
本说明书中各个实施例采用递进的方式描述， 每个实施例重点说明的都是与其 他实施例的不同之处， 各个实施例之间相同相似部分互相参见即可。
以上所述仅为本发明的实施方式， 并非因此限制本发明的专利范围， 凡是利用 本发明说明书及附图内容所作的等效结构或等效流程变换， 或直接或间接运用在其 他相关的技术领域， 均同理包括在本发明的专利保护范围内。

Claims

权 利 要 求 书
1、 一种投影装置， 其特征在于， 包括：
激光光源和铁电液晶光阀， 所述铁电液晶光阀用于接收激光光源发出的 光， 并根据输入图像信号对该光进行调制并出射图像光；
驱动装置， 用于脉冲驱动激光光源， 使得激光光源处于点亮状态时的最 高工作电流高于其额定工作电流；
同步控制装置， 用于控制驱动装置和 /或铁电液晶光阀，使得在铁电液晶 光阀工作于显示时间段时， 激光光源处于点亮状态， 在铁电液晶光阀工作于 反图像时间段时， 激光光源处于关闭状态。
2、 根据权利要求 1所述的投影装置， 其特征在于：
所述激光光源处于点亮状态时的最高工作电流为额定工作电流的二倍。
3、 根据权利要求 1所述的投影装置， 其特征在于：
所述驱动装置还用于获取用户亮度要求等级， 并获取与该等级对应的激 光光源的工作电流， 并控制所述激光光源工作于该获取的工作电流； 用户亮度 要求等级的最高等级所对应的激光光源的工作电流是所述最高工作电流。
4、 根据权利要求 1所述的投影装置， 其特征在于：
铁电液晶光阀的数量是一片， 所述驱动装置驱动激光光源分时产生至少 两种不同颜色的光构成时序光， 该时序光入射于铁电液晶光阀并被其分时调 制；
同步控制装置还用于控制驱动装置和 /或铁电液晶光阀，使得铁电液晶光 阀所调制的所述图像信号的颜色， 与驱动装置驱动激光光源所产生的光的颜色 保持同步。
5、 根据权利要求 4所述的投影装置， 其特征在于：
所述激光光源包括至少两种颜色的激光组件， 所述驱动装置分时控制该 至少两种颜色的激光组件形成所述时序光； 或者， 所述激光光源包括至少两个 激光组件和至少一个波长转换装置，至少一个激光组件入射于所述至少一个波 长转换装置并使其产生受激光， 所述驱动装置分时控制所述至少两个激光组件 形成所述时序光；
同步控制装置控制驱动装置和 /或铁电液晶光阀，使得在铁电液晶光阀工 作于显示时间段时， 相对应的颜色的激光组件处于点亮状态而其它激光组件处 于关闭状态。
6、 根据权利要求 4所述的投影装置， 其特征在于：
所述激光光源包括一个激光组件和一个波长转换轮 , 该波长转换轮包括 至少两个颜色区， 该两个颜色区分别包括两种波长转换材料或者分别包括一种 波长转换材料和散射材料， 所述激光组件发出的激光依次入射于所述波长转换 轮的至少两个颜色区以形成所述时序光；
还包括探测装置， 用于探测波长转换轮的转动位置， 并产生反映波长转 换轮的转动位置的周期性信号；
所述同步控制装置根据所述周期性信号控制铁电液晶光阀使得铁电液 晶光阀所调制的图像信号的颜色与激光光源所产生的光的颜色保持同步。
7、 根据权利要求 6所述的投影装置， 其特征在于：
所述同步控制装置控制铁电液晶光阀， 使得当所述波长转换轮的至少一 个轮辐区处于所述激光组件发射的激光的光路上时， 铁电液晶光阀工作于至少 一个反图像时间段。
8、 根据权利要求 1所述的投影装置， 其特征在于：
铁电液晶光阀的数量是两片或以上， 所述驱动装置驱动激光光源产生与 铁电液晶光阀数量相同的若干个基色光并分别入射于对应的铁电液晶光阀并 被分别调制。
9、 根据权利要求 8所述的投影装置， 其特征在于：
激光光源包括白光组件和波长分光装置， 该白光组件发出的白光经过波 长分光装置分光产生与铁电液晶光阀数量相同的若干个基色光；
所述白光组件包括激光组件和波长转换装置， 波长转换装置至少部分吸 收激光组件发出的激光并发射受激光， 该受激光或者所述激光组件发射的激光 中没有被波长转换装置吸收的部分与该受激光形成的混合光成为该白光组件 的出射光。
10、 根据权利要求 8所述的投影装置， 其特征在于：
所述激光光源包括与铁电液晶光阀数量相同的若干个基色光激光组件， 它们发射的若干束基色光分别入射于对应的铁电液晶光阀并被其分别调制； 同步控制装置用于控制相对应的至少一对驱动装置和 /或铁电液晶光阀， 使得在铁电液晶光阀工作于显示时间段时， 激光光源处于点亮状态， 在铁电液 晶光阀工作于反图像时间段时， 激光光源处于关闭状态。
11、 根据权利要求 10所述的投影装置， 其特征在于：
至少一个所述基色光激光组件包括激光激发源和波长转换装置， 激光激 发源发射的激光入射于波长转换装置并激发产生受激光， 该受激光是该基色光 激光组件发射的基色光。
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