JP2018060077A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projection device that can perform accurate color correction compared with the prior art.SOLUTION: An image forming apparatus (100) comprises: a light source part (50); light modulation elements (28, 29, and 30) that modulate light from the light source part; an optical sensor (13) that acquires light information on the light from the light source part; and a control part (40) that controls the optical sensor to acquire the light information while controlling the light modulation elements to output images corresponding to specific image data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image projection apparatus that projects light from an image display element.

  Conventionally, an image projection apparatus including a phosphor is known. In such an image projection apparatus, the phosphor functions as a wavelength conversion element that converts part of the light emitted from the light source into light longer than the wavelength of the light. However, since the color changes due to the characteristics and deterioration of the phosphor, it is necessary to perform color correction according to the characteristics and deterioration of the phosphor.

  In Patent Document 1, in order to adjust the color balance, the second light amount is controlled to be constant based on the first light amount and the second light amount from the light amount monitor, and the modulation amount of the first light amount by the light modulation device is controlled. A projector including a control unit that performs the above-described control is disclosed. In Patent Document 2, in order to prevent the occurrence of a color change due to the deterioration of the phosphor, the phosphor is detected from the detection result of the detection device that detects the light reflected by the reflection optical system that reflects a part of the light from the phosphor. A projector including a control device that determines the deterioration state of the projector is disclosed.

Japanese Patent No. 5593703 Japanese Patent No. 57033631

  However, in the projector of Patent Document 1, when the tone of the light modulation device changes every time the color balance is adjusted, the color and brightness of the light returning to the light amount monitor change, resulting in a control error. In the projector of Patent Document 2, when the gradation of the light modulation device is different every time the deterioration state of the phosphor is determined, the color and brightness returned to the detection device change, and a detection error occurs.

  SUMMARY An advantage of some aspects of the invention is that it provides an image projection apparatus capable of performing color correction with higher accuracy than before.

  An image projection apparatus according to one aspect of the present invention includes a light source unit, a light modulation element that modulates light from the light source unit, a light sensor that acquires light information about the light from the light source unit, and a specific image. And a control unit that controls the optical sensor so as to acquire the optical information in a state where the optical modulation element is controlled to output an image corresponding to data.

  Other objects and features of the present invention are illustrated in the following examples.

  According to the present invention, it is possible to provide an image projection apparatus capable of performing color correction with higher accuracy than before.

1 is a configuration diagram of an image projection apparatus in Embodiment 1. FIG. In Example 1, it is a related figure of the electric current value of a laser light source, and the brightness acquired by the optical sensor. In Example 1, it is a relationship figure between the electric current value of a laser light source, and the brightness acquired from the illuminometer. In Example 1, it is a related figure of the electric current value of a laser light source, and a brightness ratio. In Example 1, it is a relationship figure of the gain of a reflection type liquid crystal display element, and a brightness ratio. In Example 1, it is a related figure of the electric current value of the laser light source, and the brightness acquired by the optical sensor in the case where each gradation is black display and white display. FIG. 6 is a configuration diagram of an image projection apparatus in Embodiment 2. In Example 2, it is a related figure of the brightness acquired by the electric current value of the laser light source, and the brightness | luminance acquired in the case where each gradation is black display and white display.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, the configuration of an image projection apparatus (projector) in Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram of the image projection apparatus 100.

  The image projection device 100 includes a light source unit 50 (light source device). The light source unit 50 is a unit that can store a light source. In this embodiment, the light source unit 50 includes a laser light source 1, a collimator lens 2, a dichroic mirror (or half mirror) 3, condenser lenses 4 and 5, and a phosphor 6. Have.

  The laser light source 1 (light source such as an excitation light source) is a laser diode that emits excitation light (blue band light or ultraviolet band light) in a first wavelength band. A light beam (excitation light) emitted from the laser light source 1 is a divergent light beam, and is converted into a parallel light beam by the collimator lens 2 disposed immediately after the laser light source 1. The laser beam emitted from the collimator lens 2 is reflected by the dichroic mirror 3 and travels toward the condenser lenses 4 and 5. The dichroic mirror 3 has a minimum necessary size for reflecting the light beam from the collimator lens 2. The surface of the dichroic mirror 3 is coated with a dielectric multilayer film that reflects the wavelength light emitted from the laser light source 1 (the light having the wavelength of the laser light source 1) but transmits the fluorescent light (converted light) wavelength. Has been.

  The light beam reflected by the dichroic mirror 3 enters the condenser lenses 4 and 5. In FIG. 1, the condenser lens unit is composed of two lenses (condenser lenses 4 and 5) having positive power, but is not limited to this. The condenser lens unit may be composed of one lens or three or more lenses. The condenser lenses 4 and 5 collect and superimpose the divided light beams to form a laser beam spot uniformly on the phosphor (phosphor unit) 6.

  The phosphor 6 converts blue band light (or ultraviolet band light) emitted from the laser light source 1 into green band light and red band light (performs fluorescence conversion) and also converts light (green band light and red band light). Is superimposed on the return light (blue band light) and reflected to generate white light. Thus, the phosphor 6 is a wavelength conversion element that converts the excitation light into converted light in the second wavelength band that is longer than the first wavelength band. In this embodiment, the light source unit 50 that converts the wavelength of light from the laser light source 1 with the phosphor 6 is used. However, the present invention is not limited to this, and other light sources such as a light source unit including a white light source are used. May be used.

  The image projection apparatus 100 has an illumination optical system 60. The illumination optical system 60 illuminates reflective liquid crystal display elements 28, 29, and 30 (light modulation elements), which will be described later, using the light flux from the light source unit 50. The illumination optical system 60 includes a collimator lens 7, fly-eye lenses 8 and 9, a PS conversion element (polarization conversion element) 10, a condenser lens 11, a mirror 12, an optical sensor 13, and a lens 14.

  The light beam from the light source unit 50 is guided to the fly-eye lenses 8 and 9 through the collimator lens 7 and enters the PS conversion element 10. The PS conversion element 10 is configured to align the polarization direction of the incident light beam in a predetermined direction (to adjust to P-polarized light). The light beam from the PS conversion element 10 is reflected by the mirror 12 via the condenser lens 11. The optical sensor 13 is disposed in the vicinity of the mirror 12 (on the incident side of the light modulation element), and receives optical information (light intensity or brightness) related to the light flux from the light source unit 50 by receiving leakage light from the mirror 12. To get. The light beam reflected by the mirror 12 is guided to the color separation / synthesis unit 70 via the lens 14.

  The color separation / synthesis unit 70 includes a dichroic mirror 21, polarizing beam splitters 22 and 23, a color selective wavelength plate 24, phase plates 25, 26 and 27, reflective liquid crystal display elements 28, 29 and 30, and a color synthesis prism 31. Have The dichroic mirror 21 transmits green band light and reflects blue band light and red band light. The green band light that has passed through the dichroic mirror 21 enters the polarization beam splitter 22, passes through the phase plate 27, and enters the reflective liquid crystal display element 30 (third light modulation element). On the other hand, the color selective wave plate 24 converts the polarization direction of the blue band light of the blue band light and the red band light reflected by the dichroic mirror 21 by 90 ° into S polarization, and the red band light remains P polarization. In this state, the light is incident on the polarization beam splitter 23. The red band light that is P-polarized light is transmitted through the polarization beam splitter 23, and the blue band light that is S-polarized light is reflected by the polarization beam splitter 23. Thereby, the light incident on the polarization beam splitter 23 is separated into blue band light and red band light whose polarization directions are orthogonal to each other. The blue band light reflected from the polarization beam splitter 23 passes through the phase plate 25 and enters the reflective liquid crystal display element 28 (first light modulation element). The red band light that has passed through the polarization beam splitter 23 passes through the phase plate 26 and enters the reflective liquid crystal display element 29 (second light modulation element).

  Each of the reflective liquid crystal display elements 28, 29, and 30 modulates incident light (light from the light source unit 50) according to an image signal (driving signal) and reflects the light, thereby forming image light (image). Display element). The green band light reflected after being subjected to 180 ° phase difference modulation by the reflective liquid crystal display element 30 passes through the phase plate 27, becomes S-polarized light, reflects off the polarization beam splitter 22, and enters the color synthesis prism 31. The red band light reflected after being subjected to 180 ° phase difference modulation by the reflective liquid crystal display element 29 is transmitted through the phase plate 26, becomes S-polarized light, reflects off the polarization beam splitter 23, and enters the color synthesis prism 31. The blue band light reflected after being subjected to 180 ° phase difference modulation by the reflective liquid crystal display element 28 is transmitted through the phase plate 25, converted to P-polarized light, transmitted through the polarization beam splitter 23, and incident on the color combining prism 31. The color synthesizing prism 31 synthesizes light in all wavelength bands of red (R), green (G), and blue (B) and outputs the combined light to the projection optical system (projection lens) 80. The projection optical system 80 projects the combined light (projection light) from the color combining prism 31 onto a projection surface such as a screen (not shown). In this embodiment, the portion of the color separation / synthesis unit 70 excluding the reflective liquid crystal display elements 28, 29, and 30 is referred to as a color separation / synthesis system.

  The control unit 40 controls the optical sensor 13 so as to acquire optical information in a state where the reflective liquid crystal display elements 28, 29, and 30 are controlled so as to output an image corresponding to specific image data. The specific image data is specific image data (image signal) input to the reflective liquid crystal display elements 28, 29, and 30. Further, the state in which the reflective liquid crystal display element is controlled to output an image corresponding to specific image data is a predetermined state in which the return light from the reflective liquid crystal display element to the optical sensor 13 is the same as at the time of initial setting. It means that it is in a state (same gradation). That is, the control unit 40 causes the optical sensor 13 to acquire optical information in a state where the gradation of the reflective liquid crystal display elements 28, 29, and 30 is a specific gradation (for example, a black gradation or a low gradation). Control. The storage unit 42 is a memory that stores various data used in the control by the control unit 40.

  Next, a change in color regarding light emitted from the image projection apparatus 100 (light source unit 50) will be described. The phosphor 6 generally has a characteristic of luminance saturation. This is a characteristic that the conversion efficiency decreases as the light intensity incident on the phosphor 6 increases. For example, when green band light and red band light are fluorescently emitted with respect to blue band light (blue excitation light), if the blue excitation light is increased, the conversion efficiency of green and red with respect to the blue light intensity is increased. Decreases and the bluishness becomes stronger. When the light intensity is changed by intentionally dimming the excitation light of the laser light source 1, the light intensity to the phosphor 6 changes and the color of the light source unit 50 changes. In addition, the excitation light deteriorates when used for a long time, and the light intensity of the excitation light decreases. When the light intensity of the excitation light decreases, the light intensity irradiated on the phosphor 6 decreases, but the phosphor 6 has a characteristic of luminance saturation, and emits fluorescence according to the light intensity irradiated on the phosphor 6. Efficiency and color change. Accordingly, when the light intensity of the excitation light is lowered due to long-term use, the color of the light source unit 50 including the phosphor 6 changes. Further, the excitation light is not only changed in excitation light intensity due to long-time use, but also when the light intensity is changed by intentionally dimming the excitation light, the light intensity to the phosphor 6 changes and the light source is saturated due to luminance saturation. The color of the part 50 changes. The phosphor 6 has a characteristic of temperature quenching accompanying a temperature change. The color of the light source unit 50 also changes depending on such characteristics. Since the color change due to the phosphor 6 occurs due to various factors as described above, in this embodiment, the color of the light source unit 50 is corrected (color correction is performed) using the optical sensor 13.

  Next, color correction (color correction) in the present embodiment will be described with reference to FIGS. FIG. 2 is a relationship diagram between the current value of the laser light source 1 and the amount of light acquired by the optical sensor 13, that is, the brightness (light information). The horizontal axis represents the current value of the laser light source 1, and the vertical axis represents the optical sensor 13. The brightness acquired by each is shown. First, when the brightness acquired by the optical sensor 13 is changed by changing the current value of the laser light source 1, a graph as shown in FIG. 2 is obtained.

  Subsequently, an illuminometer (not shown) is disposed at the projection position of the projection light from the image projection apparatus 100 (outside of the image projection apparatus 100). Here, the reflective liquid crystal display elements 28, 29, and 30 in the blue, red, and green light paths are alternately displayed with the maximum gradation, and the current value of the laser light source 1 is changed to change the brightness step by step. Then, the brightness (Ev value) in each optical path is acquired using an illuminometer. When displaying the maximum gradation of the reflective liquid crystal display element 28 in the blue light path, the red and green reflective liquid crystal display elements 29 and 30 are displayed in black. In addition, when the brightness at the time of displaying the maximum gradation of green is obtained from the illuminance meter, the blue and red reflective liquid crystal display elements 28 and 29 are displayed in black. Further, when the brightness at the time of displaying the maximum gray level of red is obtained from the illuminance meter, the blue and green reflective liquid crystal display elements 28 and 30 are displayed in black. As described above, when the brightness of each optical path with respect to the current value of the laser light source 1 is obtained using the illuminometer, a graph as shown in FIG. 3 is obtained. FIG. 3 is a relationship diagram between the current value of the laser light source 1 and the brightness acquired from the illuminometer, where the horizontal axis indicates the current value of the laser light source 1 and the vertical axis indicates the brightness acquired from the illuminometer. Yes.

  Subsequently, as shown in FIG. 4, the numerical values of FIG. 3 are calculated so that the degree of color can be understood. FIG. 4 shows the current value of the laser light source 1, the brightness ratio (red / blue) between the red light path and the blue light path acquired from the illuminometer, and the brightness between the green light path and the blue light path acquired from the illuminometer. It is a relationship diagram with a ratio (green / blue). In FIG. 4, the horizontal axis represents the current value of the laser light source 1, and the vertical axis represents the brightness ratio (red / blue, green / blue). As shown in FIG. 4, the brightness ratio (red / blue, green / blue) decreases as the current value of the laser light source 1 increases. This is because, due to the luminance saturation characteristic of the phosphor 6, as the light intensity incident on the phosphor 6 increases, the ratio of converting the blue band light to the green band light and the red band light decreases, and the color becomes blue. It shows that the color will be close.

  In order to reduce such a change in color, the control unit 40 performs color correction on the reflective liquid crystal display element based on the optical information acquired by the optical sensor 13. Preferably, the optical sensor 13 acquires the light intensity (brightness) related to the light from the light source unit 50 as the optical information, and the control unit 40 determines the light intensity and the color information of the projection light (the color acquired by the illuminometer). And color correction related to the reflective liquid crystal display element. Preferably, the storage unit 42 stores data indicating the relationship between the light intensity and the color information, and the control unit 40 performs color correction related to the reflective liquid crystal display element based on the data.

  In the present embodiment, the control unit 40 performs gain correction for at least one of the reflective liquid crystal display elements 28, 29, and 30 (gamma characteristics thereof) as color correction. When the color of the phosphor 6 changes, for example, the gain of the red and green reflective liquid crystal display elements 29 and 30 is changed to adjust the color. That is, in this embodiment, the light modulation elements are reflective liquid crystal display elements 28, 29, and 30 (first light modulation element and second light modulation element) that modulate blue band light, red band light, and green band light, respectively. , And a third light modulation element). At this time, the control unit 40 performs gain correction by reducing the gain of the reflective liquid crystal display elements 29 and 30 (second light modulation element and third light modulation element). Alternatively, the control unit 40 performs gain correction by increasing the gain of the reflective liquid crystal display element 28 (first light modulation element). Alternatively, the control unit 40 may perform gain correction by reducing the gain of the reflective liquid crystal display elements 29 and 30 and increasing the gain of the reflective liquid crystal display element 28.

  FIG. 5 is a relationship diagram between the gains of the red and green reflective liquid crystal display elements 29 and 30 and the brightness ratio (red / blue, green / blue). In FIG. 5, the horizontal axis represents the gains of the red and green reflective liquid crystal display elements 29 and 30, and the vertical axis represents the brightness ratio. For example, when the current value of the laser light source 1 is changed from A to B as shown in FIG. 4, the brightness ratio, that is, the color changes. Here, the gains of the red and green reflective liquid crystal display elements 29 and 30 are changed from A ′ to B ′ as shown in FIG. 5 so as to correct the changed brightness ratio (color tone) of the same amount. To do. Thereby, the color of the current value B of the laser light source 1 shown in FIG. 4 can be returned to the color of the current value A. As a result, even when the current value of the laser light source 1 is changed, the brightness ratio of green and blue and red and blue (green / blue, red / blue), that is, the color can be kept substantially constant.

  Further, when the laser light source 1 is used for a long time, the brightness of the laser light source 1 is lowered. For example, let us consider a case where the brightness corresponding to the current value A of the laser light source 1 in FIG. 2 is the same current value A but decreases to the brightness corresponding to the current value B due to deterioration due to long-term use. At this time, due to the luminance saturation characteristic of the phosphor 6, the respective brightness ratios of green and blue and red and blue also correspond to the current values A and B of the laser light source 1 in FIG. 4. become. At this time, the brightness (light quantity) acquired using the optical sensor 13 decreases from the current value A to the brightness corresponding to the current value B. Therefore, in this embodiment, when the gains of the red and green reflective liquid crystal display elements 29 and 30 in FIG. 5 are changed, the red and blue brightness ratios and the green and blue brightness ratios cause the deterioration. Correct the changed amount of the same color (perform color correction). That is, the control unit 40 changes the gain of each of the red and green reflective liquid crystal display elements 29 and 30 from A ′ to B ′ (by performing gain correction), and changes the deteriorated color of the laser light source 1 to the initial value. Return to color. Thereby, even when the brightness of the laser light source 1 changes due to deterioration, the color can be kept constant.

  In this embodiment, there is return light from the reflective liquid crystal display elements 28, 29, 30 to the optical sensor 13, as indicated by the dotted arrows in FIG. In addition, the intensity of the return light (optical information) changes according to the gradation of the reflective liquid crystal display elements 28, 29, and 30. That is, as the gradation of the reflective liquid crystal display elements 28, 29, and 30 is increased from the minimum gradation (black display) to a higher gradation (closer to white display), the return light becomes weaker. As described above, even when the current of the laser light source 1 is the same, when the gradation of the reflective liquid crystal display elements 28, 29, and 30 is black display due to the influence of the return light, it is acquired by the optical sensor 13 than in the case of white display. The brightness will be brighter. The difference in brightness according to the gradation causes a color correction error.

  Here, color correction when the laser light source 1 is used for a long time will be described. For example, from the brightness corresponding to the current value A of the laser light source 1 in FIG. 2 (initial brightness), the brightness corresponding to the current value B due to deterioration with the same current value A but with long-term use (after long-term use deterioration) Let us consider a case where the brightness is reduced to (brightness). At this time, the brightness ratios of green and blue and red and blue are based on the brightness ratio (initial brightness ratio) corresponding to the current value A of the laser light source 1 in FIG. The brightness ratio corresponding to the current value B (the brightness ratio after long-term use deterioration) is obtained. At this time, when the brightness is acquired using the optical sensor 13, the brightness of the laser light source 1 is reduced from the brightness corresponding to the current value A to the brightness corresponding to the current value B.

  FIG. 6 is a relationship diagram between the current value of the laser light source 1 and the brightness acquired by the optical sensor 13 in each of the minimum gradation (black display) and the maximum gradation (white display). The current value of the laser light source 1 and the vertical axis indicate the brightness acquired by the optical sensor 13, respectively. As shown in FIG. 6, when the gradation of the reflective liquid crystal display elements 28, 29, and 30 is switched between black display and white display, it is acquired by the optical sensor 13 due to the influence of return light to the optical sensor 13. The brightness that is changed. For this reason, in order to perform highly accurate color correction, it is preferable to always use the same gradation (for example, black display or white display) when acquiring optical information (brightness) using the optical sensor 13. .

  Here, with reference to FIG. 6, the case where a conventional error occurs will be described. Assume a case where the gradation of the reflective liquid crystal display element is set to black display at the initial use of the image projection apparatus, and the gradation is set to white display after long-term deterioration. At this time, as shown in FIG. 6, the black display corresponding to the current value B of the deteriorated laser light source 1 from the brightness in the case of the black display Δ corresponding to the current value A of the laser light source 1 in the initial stage. It has deteriorated to the brightness of Δ. However, if the gradation is displayed in white after the deterioration, it is determined that the brightness has deteriorated to the brightness of the white display ▽ corresponding to the current value B of the laser light source 1 after the deterioration. For this reason, it is determined that the brightness is deteriorated by an error α due to actual brightness deterioration (black display Δ corresponding to the current value B), and the error α is generated. As a result, the gain α of the reflective liquid crystal display element shown in FIG. That is, although it is only necessary to correct from the initial gain A ′ to the gain B ′, the gain correction is performed so that the brightness error α is larger than the gain B ′. As a result, an error occurs in the color correction amount, resulting in a decrease in accuracy.

  Therefore, in this embodiment, when the brightness of the optical sensor 13 with respect to the initial current value of the laser light source 1 is acquired, and when the brightness of the optical sensor 13 is acquired when color correction is performed after deterioration of the light source unit. In any case, the gradation of the reflective liquid crystal display element is set to the minimum gradation (black display). As a result, it is possible to reduce the influence of the error and realize highly accurate color correction. Note that setting the gradation to the minimum gradation has the advantage that the display image becomes black when color correction is performed and the user does not care. However, the gradation is not limited to the minimum gradation, and may be set to a low gradation (50% or less of the maximum brightness of the reflective liquid crystal display element). Further, in this embodiment, from the viewpoint of performing highly accurate color correction, as long as the same gradation is displayed when the optical information is acquired using the optical sensor 13, the gradation is white display or bright gradation. (High gradation) may be used.

  Next, with reference to FIG. 7 and FIG. 8, an image projection apparatus in Embodiment 2 of the present invention will be described. FIG. 7 is a configuration diagram of the image projection apparatus 100a. In the image projection apparatus 100a, the optical sensor 13 is arranged in the vicinity of the mirror 12 (incident side of the light modulation element) in that the optical sensor 13 is arranged in the vicinity of the color synthesizing prism 31 (exit side of the light modulation element). This is different from the image projection apparatus 100 of the first embodiment. Since the other structure of the image projection apparatus 100a is the same as that of the image projection apparatus 100, those description is abbreviate | omitted.

  In FIG. 7, the solid line indicates the light beam displayed by the reflective liquid crystal display elements 28, 29, and 30, and the dotted line indicates the leaked light from the color synthesis prism 31. The optical sensor 13 disposed in the vicinity of the color synthesis prism 31 acquires leakage light indicated by a dotted line. Also in the present embodiment, when the gradation of the reflective liquid crystal display elements 28, 29, and 30 changes, the amount of leakage light from the color synthesis prism 31 changes. As a result, the amount of light acquired by the optical sensor 13 changes, resulting in a color correction error.

  FIG. 8 is a relationship diagram between the current value of the laser light source 1 and the brightness acquired by the optical sensor 13 in each case of the minimum gradation (black display) and the maximum gradation (white display). The current value of the laser light source 1 and the vertical axis indicate the brightness acquired by the optical sensor 13, respectively. As shown in FIG. 8, even if the current amount of the laser light source 1 is the same, the brightness of the optical sensor 13 becomes brighter when the gradation is white display than when black is displayed due to the influence of the return light. This difference causes a color correction error. In the first embodiment, the optical sensor 13 is disposed on the incident side of the reflective liquid crystal display element. However, in the present embodiment, the optical sensor 13 is disposed on the outgoing side of the reflective liquid crystal display element. For this reason, in this embodiment (FIG. 8), compared with the first embodiment (FIG. 6), the return light to the photosensor 13 in each of the black display and the white display is reversed, and the brightness relationship is reversed. ing. However, since the basic concept is the same as that of the first embodiment (FIG. 6), the description thereof is omitted.

  In the present embodiment, when the brightness of the optical sensor 13 with respect to the initial current value of the laser light source 1 is acquired, and when the brightness of the optical sensor 13 is acquired when color correction is performed after deterioration of the light source unit. In any case, the gradation of the reflective liquid crystal display element is set to a specific gradation (for example, black display). As a result, it is possible to reduce the influence of the error and realize highly accurate color correction.

  The image projection apparatus of each embodiment includes a light source unit that can emit fluorescence by irradiating a phosphor with excitation light using a solid-state light source such as a laser light source and output a wavelength band in the entire visible range. Although it has, it is not limited to this. Each embodiment can also be applied to an image projection apparatus having another light source unit such as a white light source. The light modulation element is not limited to a reflective liquid crystal display element, and may be a transmissive liquid crystal display element or another light modulation element such as a DMD.

  According to each embodiment, it is possible to provide an image projection apparatus capable of performing color correction with higher accuracy than before.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

13 Optical sensor 28, 29, 30 Reflective liquid crystal display element (light modulation element)
40 control unit 50 light source unit 100, 100a image projection device

Claims (17)

A light source unit;
A light modulation element that modulates light from the light source unit;
An optical sensor for acquiring optical information relating to the light from the light source unit;
And a control unit that controls the optical sensor so as to acquire the optical information in a state where the optical modulation element is controlled to output an image corresponding to specific image data. apparatus.   The image projection apparatus according to claim 1, wherein the control unit controls the optical sensor so as to acquire the optical information in a state where a gradation of the light modulation element is set to a specific gradation.   3. The image projection according to claim 2, wherein, when the optical information is acquired using the optical sensor, the control unit always sets the gradation of the light modulation element to the specific gradation. 4. apparatus.   4. The image projection apparatus according to claim 1, wherein the control unit performs color correction on the light modulation element based on the optical information acquired by the optical sensor. 5. The optical sensor acquires the light intensity related to the light from the light source unit as the optical information,
The image control apparatus according to claim 4, wherein the control unit performs the color correction related to the light modulation element based on the light intensity and color information of the projection light. A storage unit that stores data indicating a relationship between the light intensity and the color information;
The image projection apparatus according to claim 5, wherein the control unit performs the color correction related to the light modulation element based on the data.   The image projection apparatus according to claim 4, wherein the control unit performs gain correction on the light modulation element as the color correction. The light source unit is
A light source that emits excitation light;
A wavelength conversion element that converts the excitation light into converted light longer than the wavelength of the excitation light, and
The light modulation element is
A first light modulation element for modulating blue band light;
A second light modulation element for modulating red band light;
The image projection apparatus according to claim 7, further comprising a third light modulation element that modulates green band light.   The image projection apparatus according to claim 8, wherein the control unit performs the gain correction by reducing gains of the second light modulation element and the third light modulation element.   The image projection apparatus according to claim 8, wherein the control unit performs the gain correction by increasing a gain of the first light modulation element.   The said control part sets the low gradation which becomes 50% or less of the maximum brightness of this light modulation element as the said specific gradation of the said light modulation element, The any one of Claim 1 thru | or 10 characterized by the above-mentioned. The image projection apparatus of Claim 1.   The image projection apparatus according to claim 11, wherein the control unit sets a black gradation as the specific gradation of the light modulation element.   The image projection apparatus according to claim 1, wherein the light modulation element is a reflective light modulation element.   The image projection apparatus according to claim 1, wherein the light modulation element is a transmissive light modulation element.   The image projection apparatus according to claim 1, wherein the optical sensor is disposed on an incident side of the light modulation element.   The image projection apparatus according to claim 1, wherein the optical sensor is disposed on an emission side of the light modulation element.   The image projection apparatus according to claim 1, wherein the optical information acquired by the optical sensor changes according to a gradation of the light modulation element.