JP2008039957A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector in which yellowing of an image projected by the projector can be reduced and whether or not maintenance is needed can be judged on progression of the yellowing with a lapse of time. <P>SOLUTION: When the internal optical system of the projector 10 installed in a smoking room etc., is polluted by tobacco smoke and dust, attenuation of light occurs at a specific wavelength and therefore, the yellowing and the color fading of the image projected onto a screen SC occur eventually. Consequently, in the projector 10 of the embodiment, the projected image on the screen SC is made into the display state of a normal hue by forming the image in which such yellowing is canceled in advance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector for image projection used in a smoking area or other environment that is easily contaminated.

  Some conventional projectors include a signal generation unit that projects a reference white image, a light amount control unit that controls the amount of light of each color light generation element, and a chromaticity detection unit that captures the reference white image. The white balance can be adjusted by operating the light amount control means based on the output from the means (see Patent Document 1).

In addition, as another projector, the pixel data of the pixel element is referred to the error data for the adjacent pixel elements and the pixel data corresponding to the pixel elements corresponding to the pixel data with different gradations. Some of them include an element processor that corrects image data, and can achieve error dispersion according to definition and display an image with good color reproducibility (see Patent Document 2).
JP 2005-121688 A JP 2006-47901 A

  However, in the former projector, when used in a smoking area or other environment that is easily contaminated, the white balance is adjusted based on the chromaticity detection results affected by the internal optical system of the projector and the coloring of the screen. Therefore, yellowing of the image itself projected by the projector cannot be reduced. In addition, it is not easy to determine whether or not the yellowing of the image with time progresses and the maintenance exceeds the limit.

  Similarly, in the latter projector, yellowing of an image projected by the projector cannot be reduced, and it is not easy to determine whether yellowing has progressed and maintenance is required.

  Therefore, the present invention can reduce yellowing of an image projected by a projector even when used in a smoking area or other environment that is easily contaminated, and whether or not yellowing progresses over time and maintenance is necessary. An object of the present invention is to provide a projector that can determine the above.

  In order to solve the above-described problems, a first projector according to the present invention includes (a) an image optical device for image formation and image projection, (b) a use time monitoring unit that monitors a use time of the image optical device, And (c) a correction unit that causes the video optical device to form a corrected image in which the fading with respect to the projected image is reduced based on the usage time obtained by the usage time monitoring unit.

  In the projector described above, the correction unit causes the image optical device to form a corrected image in which the color fading with respect to the projection image is reduced based on the usage time obtained by the usage time monitoring unit. Based on this, it is possible to display a projected image with reduced fading over a long period of time.

  According to a specific aspect or aspect of the present invention, in the first projector, the correcting unit uses the usage time obtained by the usage time monitoring unit and the temporal fading predicted to occur according to the usage time. The relationship with the correction amount for compensating for yellowing of the image is maintained, and the relationship is used for correction. In this case, it is possible to project an image that compensates for yellowing that occurs corresponding to the usage time.

  A second projector according to the present invention includes (a) an image optical device for image formation and image projection, (b) an optical sensor that directly detects image light formed by the image optical device, and (c). And a correction unit that causes the video optical device to form a correction image in which the fading with respect to the projection image is reduced based on a change in the amount of image light obtained by the optical sensor.

  In the projector described above, the correction unit forms a corrected image in which the fading over time with respect to the projected image is reduced based on the change in the amount of image light obtained by the optical sensor. A projected image with reduced fading based on light can be displayed over a long period of time.

  According to a specific aspect of the present invention, in the second projector, the correction unit compensates for the change in the amount of light obtained by the optical sensor and the yellowing of the image as a color fading corresponding to the change in the amount of light. The relationship with the correction amount is retained, and the relationship is used for correction. In this case, it is possible to project an image in which yellowing that increases with time is reflected as being reflected in a change in the amount of image light.

  According to another aspect of the present invention, in the first and second projectors, the correction unit performs signal correction processing on the drive signal input to the light modulation unit provided in the video optical apparatus. In this case, time-dependent fading such as yellowing can be accurately reduced by image processing including hue adjustment.

  According to still another aspect of the present invention, the color separation optical system that separates the light source light into a plurality of color lights is provided, and the correction unit serves as an adjustment unit for adjusting the intensity of at least one of the plurality of color lights. Is provided. In this case, since each color light is adjusted, more accurate correction can be performed, and the effect of reducing the fading over time can be enhanced.

  According to still another aspect of the present invention, it further comprises a forcible adjustment means for forcibly adjusting the correction amount by the correction unit. In this case, it is possible to project a corrected image that is appropriately corrected independently of the usage time and the change in the amount of image light.

  According to still another aspect of the present invention, there is further provided reset means for forcibly prohibiting correction by the correction unit. In this case, it is possible to project a normal image without correction based on the usage time or the change in the amount of image light.

  According to still another aspect of the present invention, the determination means for determining whether or not the time-dependent fading of the projection image has reached an uncorrectable state, and the determination means has reached an uncorrectable state. And a warning means for performing a display related to excessive fading over time. In this case, the user can confirm that the color fading has progressed to a state where correction cannot be performed, and can confirm that the projector is contaminated with dust, dust, or the like and is in a state in which normal use is difficult.

[First Embodiment]
FIG. 1A is a perspective view illustrating the appearance of the projector according to the first embodiment of the invention. The illustrated projector 10 has a structure in which a projection lens 70 is embedded on the right side of the front surface portion of the exterior case 19, and has a cooling exhaust port 19 a on the left side of the front surface portion. A first operation unit 91 and a second operation unit 92 are formed on the top plate side of the outer case 19 so that the user can adjust or change the operating state of the projector 10 as appropriate. .

  FIG. 1B is a side view for explaining an example of the usage state of the projector 10 shown in FIG. The projector 10 may be installed in a room (for example, a smoking room) RM that is in a dirty atmosphere due to smoke generated by the smoking of the viewer who is the user US. The image light IL emitted from the projector 10 passes through the room RM and is projected onto the screen SC. Since the internal optical system of the projector 10 installed in such a room RM causes light attenuation at a specific wavelength when contamination progresses due to cigarette smoke or dust as described above, it is projected on the screen SC. The image is yellowed and faded. For this reason, in the projector 10 of this embodiment, the projection image on the screen SC is maintained in a normal color display state by forming an image corrected so as to reduce such yellowing.

  FIG. 2 is a block diagram conceptually illustrating the internal structure of the projector 10. The projector 10 includes an outer case 19 that forms an appearance, a main optical device 11 that is also called an optical engine unit, a power supply device 14 that supplies power to a lamp light source, and a cooling fan unit that cools the lamp light source and the like. 15 and a circuit device 17 for controlling the operation of the entire apparatus. The circuit device 17 is composed of electronic components mounted on a printed circuit board, and is housed in a suitable place in the outer case 19, but is shown outside the outer case 19 for convenience in the drawings. The outer case 19 has an exhaust port 19 a having a louver on the front surface and an intake port 19 b having a louver on the lower surface, so that outside air for cooling circulates in the outer case 19.

  Of these, the main optical device 11 functions as an image optical device for image formation and image projection, and generates a light source device 30 that generates illumination light with uniform light source light, and red / green illumination light passing through the light source device 30. The color separation optical system 40 that separates the three colors of blue, the light modulation unit 50 that is illuminated by the illumination light of each color emitted from the color separation optical system 40, and the modulated light of each color that has passed through the light modulation unit 50 are combined. And a projection lens 70 that projects the image light emitted from the cross dichroic prism 60 onto a screen (not shown). The light source device 30, the color separation optical system 40, the light modulation unit 50, the cross dichroic prism 60, and the projection lens 70 are substantially entirely housed in a light shielding case member 11a.

  Here, the light source device 30 includes a lamp unit 31 formed of a lamp and a concave mirror for forming parallel light source light fluxes, and the light source light emitted from the lamp unit 31 is made uniform illumination light and the illumination light is polarized with a predetermined polarization. And a homogenizing optical system 33 for converting into components.

  The color separation optical system 40 includes first and second dichroic mirrors 41a and 41b, and reflection mirrors 42a, 42b, and 42c. The color separation optical system 40 separates the illumination light that has passed through the homogenization optical system 33 into three light beams of red light, green light, and blue light. That is, the first dichroic mirror 41a reflects the red light LR among the three colors of red, green, and blue (R, G, and B) and transmits the green light LG and the blue light LB. The second dichroic mirror 41b reflects the green light LG of the incident green light LG and blue light LB and transmits the blue light LB.

  The light modulation unit 50 includes three liquid crystal light valves 51r, 51g, and 51b into which illumination lights LR, LG, and LB of three colors are incident, respectively. Each liquid crystal light valve 51r, 51g, 51b is composed of a liquid crystal panel (liquid crystal display panel) and a pair of polarizing filters sandwiching the liquid crystal panel. In the light modulator 50, the red light LR is incident on the image forming area of the liquid crystal light valve 51r, the green light LG is incident on the image forming area of the liquid crystal light valve 51g, and the blue light LB is incident on the liquid crystal light valve 51b. Incident on the image forming area. Each liquid crystal light valve 51r, 51g, 51b changes the spatial distribution of its polarization direction with respect to incident illumination light. That is, the color lights LR, LG, and LB incident on the liquid crystal light valves 51r, 51g, and 51b respectively correspond to the drive signals or control signals input as electrical signals to the liquid crystal light valves 51r, 51g, and 51b. The polarization state is adjusted in units of pixels, and the intensity is modulated in units of pixels as it passes through a polarization filter (not shown).

  The cross dichroic prism 60 is a light combining optical system for combining color images, and includes therein a first dichroic film 61 for reflecting red light and a second dichroic film 62 for reflecting blue light. It is arranged in a letter shape. The cross dichroic prism 60 reflects the red light LR from the liquid crystal light valve 51r by the first dichroic film 61, and causes the green light LG from the liquid crystal light valve 51g to travel straight through both the dichroic films 61 and 62, thereby producing a liquid crystal light. The blue light LB from the bulb 51 b is reflected by the second dichroic film 62.

Thus, the image light IL synthesized by the cross dichroic prism 60 is projected as a color image on the screen SC shown in FIG. 1B at an appropriate magnification through the projection lens 70 which is a projection optical system. Although not shown, the projection lens 70 includes a zoom / focus mechanism for adjusting the size and focus state of the projected image. Further, an optical sensor 71 is embedded in an appropriate position inside the projection lens 70 so as not to be affected by cigarette dust or dust, and the optical sensor 71 transmits image light IL passed through the projection lens 70. Can be detected. Further, the optical sensor 71 is provided with a cover (not shown) in which a SiO ₂ film having a dust-proofing effect is deposited on the surface, and is not affected by cigarette dust or dust.

  The circuit device 17 includes an image processing unit 81 to which an external image signal such as a video signal is input, a light valve driving unit 82 that drives the liquid crystal light valves 51r, 51g, and 51b based on the output of the image processing unit 81, A sensor driving unit 86 that drives the optical sensor 71 to monitor the intensity change of the image light IL, and a main control unit 88 that comprehensively controls operations of the circuit portions 81, 82, 86 and the like.

  In the circuit device 17, the image processing unit 81 includes an image correction circuit 81 a that appropriately performs correction processing on the input external image signal. The image processing unit 81, that is, the image correction circuit 81 a performs various image processing such as color correction and distortion correction on the external image signal based on a command from the main control unit 88. For example, when a yellowing correction command is output from the main control unit 88 to the image processing unit 81, the image processing unit 81 performs yellowing correction processing on the image signal based on the correction information from the main control unit 88. Apply. Specifically, in order to reduce yellowing of the projected image, the image processing unit 81 cooperates with the main control unit 88 to form a projected image close to the initial state excluding yellowing on the screen SC. That is, the image processing unit 81 or the like causes the liquid crystal light valves 51r, 51g, and 51b to form a bluish correction image that cancels such yellowing in accordance with the degree of yellowing that has occurred in the main optical device 11. As a result, the projected image on the screen SC is brought into a normal hue display state. The image processing unit 81 can perform various color corrections, gradation corrections, distortion corrections, and the like in addition to the yellowing correction as described above by the image correction circuit 81a, and a function of OSDC (on screen display control). Based on the above, it is possible to synthesize a signal for displaying various display information including character information and the like together.

  The light valve driving unit 82 generates a driving signal for adjusting the display state of each of the liquid crystal light valves 51r, 51g, 51b based on the image signal after image processing output from the image processing unit 81. Accordingly, an image corresponding to the image signal output from the image processing unit 81 can be formed in the liquid crystal light valves 51r, 51g, and 51b including the liquid crystal panel and the polarizing plates associated therewith.

  The sensor driving unit 86 functions as a measuring device together with the optical sensor 71. That is, the sensor driving unit 86 uses the optical sensor 71 to detect the amount of yellowing as a result of the main optical device 11 in the projector 10 being physically contaminated by cigarette dust or dust. The optical sensor 71 driven by the sensor driving unit 86 is yellowish by detecting the intensity of the image light IL passed through the projection lens 70 when, for example, a white image having a predetermined luminance is formed by the main optical device 11. Can be detected as a decrease in the amount of light. Further, the optical sensor 71 detects the intensity of the image light IL that is passed through the projection lens 70 when, for example, an image of each color of red, green, and blue having a predetermined luminance is formed by the main optical device 11. The progress of yellowing can be detected as a change in color balance.

  The main control unit 88 controls the overall operation of the projector 10 as a control device, and includes a microcomputer or the like, and a storage unit that is a storage unit for holding various data necessary for the operation of the projector 10. Built in 88a. The storage unit 88a stores, as, for example, a table or a conversion formula as time-dependent correction information, such as a table or a conversion formula that offsets a decrease in the amount of light of the image light IL passed through the projection lens 70 or a change in color balance. Further, the storage unit 88a stores, as a table or a conversion formula, a yellowing correction amount that offsets the progress of yellowing corresponding to the operation time of the projector 10 corresponding to the lighting time of the light source device 30 as the temporal correction information. .

  The key input unit 93 connected to the main control unit 88 corresponds to the first and second operation units 91 and 92 shown in FIG. It functions as an input device for inputting instructions. The user can perform general adjustment of the projection state by the projector 10 by operating the first operation unit 91 of the key input unit 93. In addition, the user operates the second operation unit 92 of the key input unit 93 to set / cancel the yellowing correction mode for correcting the temporal deterioration of the projection image by the projector 10 or the setting state of the yellowing correction mode. Can be changed. The key input unit 93 can be replaced with a remote control device having a similar function, or can be used in combination with such a remote control device.

表から明らかなように、ランプ点灯時間とともに色座標が変化することが分かる。このような傾向は、再現性があり、ランプ点灯時間とともに投射像の褪色が進行することが確認された。 The main control unit 88 also functions as a usage amount monitoring unit that checks the lighting time of the light source device 30, that is, the lamp lighting time. The lamp lighting time corresponds to the time during which the outside air for cooling circulates in the outer case 19 and is considered to reflect the degree of contamination of the main optical device 11 and the yellowing of the image. It is done. The following table is a table for explaining a change with time of color coordinates in the chromaticity table when the projector 10 is used in a certain room RM.

As is clear from the table, it can be seen that the color coordinates change with the lamp lighting time. Such a tendency was reproducible, and it was confirmed that the discoloration of the projected image progressed with the lamp lighting time.

  FIG. 3 is a chromaticity diagram showing the change in color coordinates when white is displayed in Table 1. The ♦ mark indicates that the lighting time is 0 hour, the ■ mark indicates that the lighting time is 180 hours, and the ▲ indicates that the lighting time is 320 hours. Indicates the color coordinates of the lighting time of 523 hours. The dotted triangle indicates the color display range displayed in the NTSC mode, and the solid triangle indicates the color display range displayed in the sRGB mode. As is apparent from the graph, the color of the projected image changes from white to yellow with the passage of time (that is, with the lamp lighting time), indicating that yellowing of the projected image has occurred.

  As described above, the lamp lighting time is a material for estimating the contamination of the main optical device 11 and can be used as a numerical value for predicting the degree of yellowing of the image. In this embodiment, the progress of yellowing corresponding to the lamp lighting time is predicted based on the graph as shown in FIG. 3, and an image in which such yellowing is compensated continuously or stepwise (discretely) is projected. . At this time, the main control unit 88 and the image processing unit 81 function as a correction unit for performing yellowing cancellation processing. For this reason, the storage unit 88a of the main control unit 88 corrects the yellowing given by the lamp lighting time and displays a table or conversion formula (of the usage time) that gives the necessary correction amount so that the original white color is displayed as white. (Including discrete coefficients corresponding to multiple stages). Specifically, the correction amount is given so that the ratio of the blue light amount is relatively increased by increasing the blue light amount that is a complementary color of yellow or decreasing the red and green light amounts. Note that the degree of yellowing can be predicted by an acceleration test that is performed several times or more in a poor environment, without actually testing the projector 10 in a similar environment.

  Hereinafter, the main operation of the projector 10 will be described focusing on the description of the operation of the main control unit 88.

  FIG. 4 is a flowchart for explaining an operation example of the projector 10. First, the main control unit 88 determines the presence or absence of an input image signal simultaneously with the startup of the projector 10 (step S11). When there is no input image signal, the main control unit 88 transmits a command for displaying that there is no input signal to the image processing unit 81 and ends this processing, and the image processing unit 81 displays an image indicating that there is no input signal. Data is prepared and the display corresponding to each liquid crystal light valve 51r, 51g, 51b is performed.

  If there is an input image signal, the main controller 88 determines whether or not the yellowing correction mode is set (step S12). The yellowing correction mode can be set by pressing one key 92a of the second operation unit 92 once, and can be canceled by pressing it again. That is, the key 92a serves as a yellowing correction mode setting unit and a resetting unit. When it is determined that the mode is not the yellowing correction mode, the main control unit 88 transmits a normal operation command to the image processing unit 81 and ends the present processing, and the image processing unit 81 ends the liquid crystal light valves 51r, 51g, 51b. In contrast, display in the normal mode is performed without correcting yellowing. Note that the display in the normal mode includes other types of color correction that are normally performed on devices in an initial state in which contamination has not progressed, and distortion correction that corrects image edge distortion and the like.

  When the yellowing correction mode is set, the main control unit 88 determines whether or not the time reference mode is set (step S13). The time reference mode is set as standard with the setting of the yellowing correction mode. The time reference mode can also be set by operating one key 92b provided on the second operation unit 92. Specifically, the time reference mode is switched to the measurement reference mode by pressing one key 92b of the second operation unit 92 once, and the measurement reference mode is switched to the time reference mode by pressing this key again.

  Hereinafter, the operation in the time reference mode will be described on the assumption that the time reference mode has been selected in step S13. The main controller 88 checks the lighting time of the light source device 30, that is, the lamp lighting time (step S14). Although a detailed description is omitted, the lamp lighting time is measured by accumulating the operation time of the power supply device 14 and the like, and is stored in the storage unit 88a as information that is sequentially updated. As described above, the lamp lighting time is considered to reflect the degree of progress of the contamination of the main optical device 11 and the yellowing of the image. In this example, the lamp lighting time is checked, but other parameters such as the image display time of the projector 10 and the cumulative installation time of the projector 10 can be checked and reflected in the yellowing correction.

  Next, the main control unit 88 selects a conversion table that provides a correction amount that corresponds to the lamp lighting time and compensates for yellowing caused thereby, and reads this conversion table from the storage unit 88a (step S15). That is, a color correction amount corresponding to the degree of progress of yellowing is set.

  Next, the main control unit 88 determines as a determination means whether or not the color correction amount set in step S15 has reached the upper limit value, that is, whether or not yellowing has reached an uncorrectable state ( Step S16). Here, the upper limit value of the color correction amount can be set from the viewpoint of avoiding deterioration of the image due to excessive color correction, but whether the yellowing exceeds the allowable range of contamination generally allowed in the main optical device 11. It can also be set based on whether or not.

  If it is determined in step S16 that the color correction amount has reached the upper limit value, the main control unit 88 displays, as a warning means, a command for displaying that yellowing has progressed excessively and the color correction amount has reached the upper limit value. It transmits to the image processing part 81 (step S17). The image processing unit 81 prepares image data that prompts the user that yellowing has proceeded excessively, that is, excessive fading has occurred, and that the main optical device 11 needs to be cleaned. A warning display corresponding to the light valves 51r, 51g, 51b is performed. Such a warning display is displayed, for example, so as not to disturb the video in a part of the projection image.

  Finally, the main control unit 88 operates the image processing unit 81 based on the color correction amount set in step S15, and the image processing unit 81 prepares image data on which the necessary color correction amount has been applied to the input image signal. Then, a projected image, that is, a corrected image is formed on each of the liquid crystal light valves 51r, 51g, 51b (step S18). Thereby, the image projected on the screen SC can be returned to a state close to the time of shipping adjustment. When warning display is performed in step S17, it is not necessary to form a projection image in this step. In this case, after performing a warning display for a certain period, the operation state of the projector 10 can be automatically shifted to, for example, the safe evacuation mode, and the display operation of the projector 10 can be stopped.

  Although omitted in the above description, the user can forcibly set the color correction amount in the yellowing correction mode. In this case, the correction amount can be increased stepwise by pressing one key 92c of the second operation unit 92 once, and the correction amount can be decreased stepwise by pressing the adjacent key 92d once. Can be made. The main controller 88 that operates based on these keys 92c and 92d and these operations serves as a forced adjustment means for the user to forcibly set the correction amount.

  In the present embodiment, since the image processing unit 81 performs image processing that corresponds to the lamp lighting time and compensates for yellowing caused by the lamp lighting time, a normal image that compensates for yellowing that occurs corresponding to the usage time of the projector 10 is long. It can project over a period of time.

[Second Embodiment]
Hereinafter, the projector according to the second embodiment will be described. Note that the projector according to the second embodiment is obtained by changing the projector according to the first embodiment mainly in terms of operation, and parts and operations not specifically described are the same as those in the first embodiment.

  FIG. 5 is a flowchart for explaining another operation example of the projector 10 according to the present embodiment. Here, the presence / absence determination of the input image signal (step S11) and the presence / absence of setting of the yellowing correction mode (step S12) are the same as those in FIG.

  When it is determined in step S12 that the yellowing correction mode is set, the main control unit 88 determines whether or not the measurement reference mode is set (step S20). The measurement reference mode can be set by operating one key 92b provided on the second operation unit 92.

  Hereinafter, the operation in the measurement reference mode will be described on the assumption that the measurement reference mode has been selected in step S20. The main control unit 88 operates the sensor driving unit 86 and the optical sensor 71 as appropriate to detect the state of the projection light, that is, the intensity of the image light IL passed through the projection lens 70 (step S21). The detection result is stored in the storage unit 88a. At this time, the main control unit 88 causes the image processing unit 81 and the liquid crystal light valves 51r, 51g, and 51b to operate appropriately to display white with appropriate luminance. As a result, it is possible to calculate a luminance decrease relative to the original or reference image luminance.

  Next, the main control unit 88 adjusts the image processing unit 81 and the liquid crystal light valves 51r, 51g, and 51b to change the wavelength of the projection image, and the projected light of the projection light is transmitted via the sensor driving unit 86 and the optical sensor 71. The state, that is, the intensity of the image light passed through the projection lens 70 is detected (step S22). Specifically, the image to be supplied to the projection lens 70 is sequentially switched to red, green, and blue image lights with appropriate luminance, and the luminance of the image light of each color at this time is measured, and the color balance shift is detected. It is measured. The measurement result is stored in the storage unit 88a. At least one of the luminance reduction and the color balance shift described above (collectively referred to as “light amount change”) reflects the contamination of the main optical device 11 and the progress of yellowing of the image. It is thought that there is.

  Next, the main control unit 88 selects a conversion table that provides a correction amount for compensating for the luminance reduction and color balance obtained in step S21 and step S22, and reads this conversion table from the storage unit 88a (step S23). . That is, a color correction amount corresponding to the degree of progress of yellowing obtained as a result of actual measurement is set.

  Next, the main controller 88 determines whether or not the color correction amount set in step S15 has reached the upper limit (step S24). Here, the upper limit value of the color correction amount is the same as that in step S16.

  When it is determined in step S24 that the color correction amount has reached the upper limit value, the main control unit 88 displays a command for displaying that the yellow correction has progressed excessively and the color correction amount has reached the upper limit value. The image processing unit 81 prepares image data for notifying that the color fading has occurred excessively and the necessity of cleaning the main optical device 11, and each of the liquid crystal light valves 51r, 51g, A related warning is displayed on 51b (step S25). Such a warning display is displayed, for example, so as not to disturb the video in a part of the projection image.

  Finally, the main control unit 88 operates the image processing unit 81 based on the color correction amount set in step S23, and the image processing unit 81 prepares image data on which the necessary color correction amount has been applied to the input image signal. Then, a projection image, that is, a corrected image is formed on each of the liquid crystal light valves 51r, 51g, 51b (step S26). When warning display is performed in step S25, it is not necessary to form a projection image in this step. In this case, after performing a warning display for a certain period, the operation state of the projector 10 can be automatically shifted to, for example, the safe evacuation mode, and the display operation of the projector 10 can be stopped.

  Although omitted in the above description, the user can forcibly set the color correction amount in the yellowing correction mode. In this case, as already described, the correction amount can be increased stepwise by pressing one key 92c of the second operation unit 92 once, and correction can be performed by pressing the adjacent key 92d once. The amount can be reduced step by step.

  In the present embodiment, since the image processing unit 81 performs image processing that compensates for yellowing directly detected by the optical sensor 71, yellowing that increases with time corresponding to the usage time of the projector 10 is applied to the image light. It is possible to project a normal image compensated as reflected in the change in the amount of light over a long period of time.

[Third Embodiment]
Hereinafter, the projector according to the third embodiment will be described. Note that the projector according to the second embodiment is obtained by partially changing the projector according to the first embodiment, and the same portions are denoted by the same reference numerals and redundant description is omitted. In addition, parts that are not particularly described are the same as those in the first embodiment.

  FIG. 6 is a plan view illustrating the projector 110 according to the third embodiment. The positions of the red and blue liquid crystal light valves 51r and 51b are oppositely arranged with respect to the first embodiment shown in FIG. The first dichroic mirror 41a reflects the blue light LB among the three colors of red, green, and blue (R, G, and B) and transmits the green light LG and the red light LR. The second dichroic mirror 41b reflects the green light LG out of the incident green light LG and red light LR and transmits the red light LR. In this case, in the color separation optical system 40, a slit device 37 is provided as an adjustment unit for color correction between the first dichroic mirror 41a and the second dichroic mirror 41b. The slit device 37 is for adjusting the intensity of the green light LG and the red light LR transmitted through the first dichroic mirror 41a by dimming. In this case, a pair of shielding plates that open and close, that is, an opening / closing slit, The aperture size (aperture amount) through which the light transmitted through the one dichroic mirror 41a passes can be changed. The slit device 37 is driven by the slit driving unit 187 to open and close, and the slit driving unit 187 operates under the control of the main control unit 88. That is, the main control unit 88 appropriately operates the slit driving unit 187 and the slit device 37 on the basis of the usage time or the degree of yellowing of the projection image obtained by the optical sensor 71 and the sensor driving unit 86, thereby generating the green light LG. By reducing the intensity of the red light LR and increasing the proportion of the amount of blue light relatively, the yellow color over time is corrected so that the original white color is displayed as white.

  Further, as an adjustment unit, that is, an adjustment unit, the intensity of the green light LG and the red light LR may be reduced by an ND filter or the like instead of the slit 37. Not only one slit and filter are arranged between the first dichroic mirror 41a and the second dichroic mirror 41b, but also a slit or filter between the color separation optical system 40 and each of the liquid crystal light valves 51r, 51g, 51b, respectively. May be arranged to adjust the intensity of each color light.

  In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can be implemented in a various aspect, For example, the following deformation | transformation is also possible.

  For example, when the degree of progress of yellowing is determined by the optical sensor 71, an image to be supplied to the projection lens 70 is sequentially switched to red, green, and blue image lights with appropriate luminance, and the image light of each color at this time is switched. Although the luminance was measured, the progress of yellowing may be determined by measuring the luminance of only the blue image light.

  In the above embodiment, the yellowing degree is determined by the use time and the optical sensor 71, but the yellowing degree can be determined by other methods. For example, the screen is irradiated with reference light from the projector 10 in advance, and the color of the screen, that is, the material color is determined from the reflected light. Thereafter, a white image or the like is projected on the screen to detect reflected light, and an absolute color balance obtained by subtracting the material color of the screen from the relative color balance of the reflected light is determined. Such an absolute color balance represents the degree of contamination of the main optical device 11, that is, the degree of yellowing of the projected image. Therefore, based on such an absolute color balance, the image processing unit 81 and the liquid crystal light valve 51r, By operating 51g, 51b, etc., it is possible to ensure that the original white color is displayed as white, and to prevent the projector 10 from being used in an excessively contaminated state. The material color of the screen only needs to be measured at the time of installation, and can be measured in advance by another measuring device and stored in the main control unit 88.

  In the above embodiment, only one conversion table or conversion formula that gives a relationship between the lamp lighting time and the correction amount is prepared. However, a plurality of conversion tables and conversion formulas can be prepared. A plurality of conversion tables can be properly used according to the degree of inferiority.

  In the above-described embodiment, the color separation of the illumination light is performed using the color separation optical system 40, the respective colors are modulated by the light modulation unit 50, and then the images of the respective colors are synthesized by the cross dichroic prism 60. However, an image can be formed by a single liquid crystal panel, that is, a liquid crystal light valve. The present invention can also be applied to a projector using two liquid crystal panels or a projector using four or more liquid crystal panels. Furthermore, the present invention can be similarly applied to a projector using a reflective liquid crystal panel or a micromirror.

(A), (b) is a figure which shows the external appearance and installation of the projector which concerns on this embodiment. It is a block diagram which shows the structure of the projector which concerns on 1st Embodiment. It is a graph explaining the relationship between a lamp lighting time and a change of a projected image. It is a figure explaining operation | movement of the projector of 1st Embodiment. It is a figure explaining operation | movement of the projector of 2nd Embodiment. It is a figure explaining the projector of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector, 11 ... Main optical device, 14 ... Power supply device, 17 ... Circuit device, 19 ... Exterior case, 30 ... Light source device, 31 ... Lamp part, 33 ... Uniformation optical system, 37 ... Slit device, 40 ... Separation Illumination system, 50: Light modulation unit, 51r, 51g, 51b ... Liquid crystal light valve, 60 ... Cross dichroic prism, 70 ... Projection lens, 71 ... Optical sensor, 81 ... Image processing unit, 82 ... Light valve drive unit, 86 ... Sensor drive unit 88 ... Main control unit 88a ... Storage unit 91,92 ... Operation unit 92a, 92b, 92c, 92d ... Key, IL ... Image light, RM ... Room, SC ... Screen

Claims (9)

An image optical device for image formation and image projection;
A usage time monitoring unit for monitoring the usage time of the imaging optical device;
A projector comprising: a correction unit that causes the video optical device to form a correction image in which a fading with respect to a projection image is reduced based on a usage time obtained by the usage amount monitoring unit.   The correction unit maintains a relationship between the use time obtained by the use time monitoring unit and a correction amount for compensating for yellowing of the image as the time-dependent fading expected to occur according to the use time. The projector according to claim 1, wherein the relationship is used for correction. An image optical device for image formation and image projection;
An optical sensor that directly detects image light formed by the imaging optical device;
A projector comprising: a correction unit that causes the video optical device to form a correction image in which a fading with respect to a projection image is reduced based on a change in the amount of image light obtained by the optical sensor.   The correction unit maintains a relationship between a light amount change obtained by the optical sensor and a correction amount for compensating for yellowing of the image as the time-dependent fading corresponding to the light amount change, and uses the relationship for correction The projector according to claim 1.   The projector according to any one of claims 1 to 4, wherein the correction unit performs a signal correction process on a drive signal input to an optical modulation unit provided in the imaging optical device.   A color separation optical system that separates light source light from a light source provided in the image optical device into a plurality of color lights, and the correction unit is an adjustment for adjusting the intensity of at least one of the plurality of color lights The projector according to claim 1, wherein the projector is provided as a section.   The projector according to claim 1, further comprising a forcible adjustment unit for forcibly adjusting a correction amount by the correction unit.   The projector according to claim 1, further comprising reset means for forcibly prohibiting correction by the correction unit.   Judgment means for judging whether or not the time-dependent fading of the projected image has reached an uncorrectable state, and if the judgment means determines that the state has reached an uncorrectable state, excessive fading over time The projector according to any one of claims 1 to 8, further comprising warning means for performing a display related to.

Images