JP2017129730A - projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector capable of displaying images with good qualities even when an illumination device is driven in a plurality of modes.SOLUTION: The projector includes: an illumination device; a color separation optical system for subjecting illumination light from the illumination device to color separation; a plurality of liquid crystal panels disposed corresponding to the colors separated by the color separation optical system; a control part having a plurality of lookup tables storing data relating to drive voltages, for controlling the plurality of liquid crystal panels by referring a table selected from the plurality of lookup tables; and a temperature sensor disposed in one of the plurality of liquid crystal panels. The control part selects a lookup table to be used for controlling the plurality of liquid crystal panels in accordance with the detection results of the temperature sensor.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a projector.

  In recent years, projectors that modulate light projected from an illuminating device with a plurality of liquid crystal panels in accordance with image information and perform enlarged projection can respond to various applications by driving the illuminating device in a plurality of modes. (For example, see Patent Document 1 below).

  This projector uses the rated power mode when viewing images from relatively distant viewers, such as corporate presentations, and visually recognizes images from relatively close viewers, such as a home theater. Use the power saving mode when The rated power mode is for irradiating light with a normal output from the lighting device, and the power saving mode is for irradiating light with a weak output from the lighting device as compared with the rated power mode.

JP 2004-207018 A

By the way, in the liquid crystal panel, the applied voltage-light transmittance characteristic (VT characteristic) and the response speed fluctuate due to a temperature change caused by the use of the projector, and the quality of the projected image is deteriorated. In the above-described rated power mode, the temperature of the liquid crystal panel is higher than that in the power saving mode, so that the VT characteristic is easily changed.
Therefore, it is conceivable to drive the liquid crystal panel based on a look-up table storing correction data for correcting variations in VT characteristics and response speed generated in the liquid crystal panel in the rated power mode.

  When the lighting device is driven in a plurality of modes as described above, the amount of change in temperature that occurs in the liquid crystal panel exceeds the temperature range that can be handled by the lookup table. Therefore, the VT characteristic of the liquid crystal panel cannot be corrected well, and the quality of the projected image may be deteriorated.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a projector capable of displaying a high-quality image even when the lighting device is driven in a plurality of modes.

  According to the aspect of the present invention, an illumination device, a color separation optical system for color-separating illumination light from the illumination device, and a plurality of liquid crystal panels arranged corresponding to each color separated by the color separation optical system A plurality of look-up tables storing data relating to drive voltages, and a control unit that controls the plurality of liquid crystal panels by referring to a table selected from the plurality of look-up tables; A temperature sensor provided in one of the liquid crystal panels, and the control unit is a projector that selects the look-up table used for controlling the plurality of liquid crystal panels based on a detection result of the temperature sensor. Provided.

  According to the projector according to the above aspect, since an optimum lookup table is selected based on the temperature of one liquid crystal panel, for example, when the lighting device is driven in the power saving mode in addition to the rated power mode, the liquid crystal panel Thus, the VT characteristic deviation occurring in the image can be corrected to suppress image quality deterioration such as color misregistration. Therefore, a high-quality image can be displayed regardless of the driving mode of the lighting device.

In the above aspect, the color separation optical system separates the white illumination light emitted from the illumination device into red, blue, and green light, and the temperature sensor is disposed corresponding to the green light. The liquid crystal panel is preferably provided.
According to this configuration, since the temperature sensor detects the temperature of the liquid crystal panel corresponding to the green light having the highest temperature among the three liquid crystal panels, the temperature sensor can detect the largest temperature difference. Become. Therefore, the temperature sensor can perform temperature detection simply and reliably.

In the above aspect, it is preferable that the lighting device includes a solid light source and a wavelength conversion element on which light emitted from the solid light source is incident.
According to this configuration, a high-quality image can be displayed even when an illumination device using a solid light source is driven in the power saving mode.

In the above aspect, it is preferable that the lighting device is driven in either a rated power mode or a power saving mode in which a lower voltage is applied to the liquid crystal panel than in the rated power mode.
According to the present invention, a high-quality image can be displayed in both the rated power mode and the power saving mode.

FIG. 2 is a schematic diagram illustrating an optical system of a projector. The figure which showed typically the electrical structure of the projector. The figure which showed the look-up table notionally.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

  FIG. 1 is a schematic diagram showing an optical system of a projector 1 according to an embodiment of the invention. In FIG. 1, reference numeral 100ax denotes an illumination optical axis, which is an optical axis of light emitted from the illumination apparatus 100 toward the color separation optical system 200.

  As shown in FIG. 1, the projector 1 includes an illumination device 100, a color separation optical system 200, a liquid crystal panel 400R, a liquid crystal panel 400G, and a liquid crystal panel 400B, a cross dichroic prism 500, and a projection optical system 600. Configured.

  The illumination device 100 includes an array light source 30 that irradiates excitation light, a condensing optical system 40, a phosphor wheel 10, a collimating optical system 60, an integrator optical system 110, a polarization conversion element 120, and a superimposing lens 130. , Are arranged in this order.

  The array light source 30 includes a plurality of semiconductor lasers 30a as solid light sources. The plurality of semiconductor lasers 30a are arranged in an array in the same plane orthogonal to the illumination optical axis 100ax. The semiconductor laser 30a emits, for example, blue light (for example, laser light having a peak wavelength of 460 nm) as the excitation light BL that excites the phosphor layer 11.

The condensing optical system 40 includes a plurality of first lenses 42 and one second lens 44.
Each of the first lens 42 and the second lens 44 is a convex lens. The light transmitted through the first lens 42 is incident on the second lens 44. The condensing optical system 40 is disposed on the beam axis of the excitation light BL emitted from the array light source 30 and condenses the excitation light BL emitted from the plurality of array light sources 30.

  The phosphor wheel 10 has a function of transmitting part of the blue excitation light BL emitted from the array light source 30 and converting the remaining excitation light BL into fluorescence. The phosphor wheel 10 has a phosphor layer 11, which absorbs the remaining excitation light BL and emits yellow fluorescence YL including red light and green light. The peak of the emission intensity of the fluorescence YL is about 550 nm. The white illumination light WL is generated by combining the fluorescence YL and the blue light BL1 that is a part of the excitation light BL transmitted through the phosphor layer 11.

  The collimating optical system 60 includes a first lens 62 as an optical element that suppresses the spread of the illumination light WL from the phosphor wheel 10 and a second lens 64 that substantially collimates the light incident from the first lens 62. ing. The first lens 62 is a pickup lens that takes in the illumination light WL emitted from the phosphor wheel 10, and is disposed in the state of being close to the phosphor wheel 10.

  The collimating optical system 60 collimates the illumination light WL emitted from the phosphor wheel 10 and causes the illumination light WL to enter the integrator optical system 110.

  The integrator optical system 110 includes a first lens array 111 and a second lens array 112. The first lens array 111 includes a plurality of lenses arranged in a matrix. The second lens array 112 includes a plurality of lenses corresponding to the plurality of lenses of the first lens array 111. The first lens array 111 divides the illumination light WL from the collimating optical system 60 into a plurality of divided light beams and collects each of the divided light beams. The second lens array 112 emits the split light flux from the first lens array 111 with an appropriate divergence angle.

  The polarization conversion element 120 includes, for example, a polarization separation film and a retardation plate, and converts the illumination light WL into linearly polarized light.

  The superimposing lens 130 superimposes the plurality of split light beams emitted from the polarization conversion element 120 in the illuminated areas of the liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B.

  The color separation optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a reflection mirror 230, a reflection mirror 240, a reflection mirror 250, a relay lens 260, and a relay lens 270. The color separation optical system 200 separates the light from the illumination device 100 into red light, green light, and blue light, and the respective color lights of red light, green light, and blue light are illuminated, the liquid crystal panel 400R and the liquid crystal panel 400G. To the liquid crystal panel 400B. A condensing lens 300R, a condensing lens 300G, and a condensing lens 300B are disposed between the color separation optical system 200 and the liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B, respectively.

  The dichroic mirror 210 transmits the red light component and reflects the green light component and the blue light component. The dichroic mirror 220 reflects the green light component of the illumination light WL reflected by the dichroic mirror 210 and transmits the blue light component.

The reflection mirror 230 reflects the red light component transmitted through the dichroic mirror 210.
The reflection mirror 240 and the reflection mirror 250 reflect the blue light component transmitted through the dichroic mirror 220.

  The red light transmitted through the dichroic mirror 210 is reflected by the reflection mirror 230, passes through the condenser lens 300R, and enters the image forming area of the liquid crystal panel 400R as a light modulator for red light. The green light reflected by the dichroic mirror 210 is further reflected by the dichroic mirror 220, passes through the condenser lens 300G, and enters the image forming area of the liquid crystal panel 400G as a light modulator for green light. The blue light transmitted through the dichroic mirror 220 passes through the relay lens 260, the reflection mirror 240, the relay lens 270, the reflection mirror 250, and the condensing lens 300B and enters the image forming area of the liquid crystal panel 400B as a light modulator for blue light. To do.

  The liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B modulate the incident color light according to image information to form an image. The liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B are illumination targets of the illumination device 100. Although not shown, incident-side polarizing plates are disposed between the condensing lens 300R, the condensing lens 300G, and the condensing lens 300B, and the liquid crystal panels 400R, 400G, and 400B. Yes. In addition, an exit-side polarizing plate is disposed between each of the liquid crystal panels 400R, 400G, 400B, and the cross dichroic prism 500.

  For example, each of the liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B includes a transmissive liquid crystal panel in which liquid crystal is hermetically sealed in a pair of transparent substrates.

  Although not shown, the cross dichroic prism 500 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the emission side polarizing plate.

  The color image emitted from the cross dichroic prism (optical element) 500 is enlarged and projected by the projection optical system 600 including a plurality of lenses, and forms an image on the screen SCR.

  By the way, in the liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B, the applied voltage-light transmittance characteristic (VT characteristic) and the response speed vary depending on the temperature change. For this reason, the projector 1 may be deteriorated in the quality of the display image with the above-described fluctuation.

Normally, the liquid crystal panel 400G corresponding to green light has a relatively large amount of incident light from the illumination device 100 compared to the other liquid crystal panels 400R and 400B. Therefore, the temperature of the liquid crystal panel 400G is likely to rise as compared with the liquid crystal panel 400R and the liquid crystal panel 400B, and as a result, the largest temperature change occurs when the projector 1 is driven.
Hereinafter, the liquid crystal panel 400R, the liquid crystal panel 400G, and the liquid crystal panel 400B may be collectively referred to as the liquid crystal panels 400R, 400G, and 400B.

  The projector 1 according to the present embodiment detects the temperature of the liquid crystal panel 400G at which the greatest temperature change occurs, and based on the detection result, drives the liquid crystal panels 400R, 400G, and 400B so that the variation in the VT characteristic is reduced. I am letting.

FIG. 2 is a diagram schematically showing the electrical configuration of the projector 1.
As shown in FIG. 2, the projector 1 of the present embodiment controls the driving of the liquid crystal panels 400R, 400G, and 400B based on the temperature sensor 70 that detects the temperature of the liquid crystal panel 400G and the detection result of the temperature sensor 70. And a control unit 90.

Since the temperature sensor 70 detects the temperature of the liquid crystal panel 400G at which the largest temperature change occurs, the temperature detection can be performed easily and reliably.
Since the projector 1 according to the present embodiment employs a configuration in which the temperature of one liquid crystal panel 400G is detected by one temperature sensor 70, the device configuration can be simplified.

  In the present embodiment, a thermistor or a thermocouple is used as the temperature sensor 70. The temperature sensor 70 is provided at a position that does not block incident light on the liquid crystal panel 400G, for example. The temperature sensor 70 is electrically connected to the control unit 90 and transmits the detection result to the control unit 90.

  The control unit 90 stores a look-up table (Look Up Table) that stores data in which the temperature of the liquid crystal panel 400G transmitted from the temperature sensor 70 is associated with the driving voltage for driving the liquid crystal panels 400R, 400G, and 400B. ing. Note that the lookup table is calculated based on, for example, an experiment performed in advance.

  Specifically, the look-up table shows the relationship between the temperature of the liquid crystal panel 400G and the driving voltage that corrects the variation in the VT characteristic generated in the liquid crystal panels 400R, 400G, and 400B based on the temperature of the liquid crystal panel 400G. Is stored. Usually, the look-up table can correct a variation in the VT characteristic of the liquid crystal panel that causes a temperature change of about ± 10 ° C.

  By the way, in recent years, reduction of power consumption (energy saving) is also desired for projectors. The projector 1 according to the present embodiment can be switched between a rated power mode in which the lighting device 100 is driven with rated power and a power saving mode in which the lighting device 100 is driven with power saving, depending on the use of the viewer. .

  The power saving mode is a mode in which the power consumption of the array light source 30 is suppressed by reducing the number of semiconductor lasers 30a to be driven with respect to the rated power mode.

Here, in the power saving mode and the rated power mode, the amount of illumination light WL emitted from the illumination device 100 is different. Therefore, in the projector 1 corresponding to the power saving mode and the rated power mode, the detected temperature region in the temperature sensor 70 is wider than that of the projector corresponding to the single power mode. That is, in each liquid crystal panel, a temperature change that is wider (for example, ± 20 ° C.) than the temperature range (± 10 ° C.) that can be satisfactorily corrected with one look-up table occurs.
As described above, in a printer that supports a plurality of power modes, it is difficult to satisfactorily correct a variation in the VT characteristic generated in each liquid crystal panel with only one lookup table.

On the other hand, the control unit 90 of the present embodiment includes a lookup table for correcting a variation in VT characteristics that occurs when the temperature detected by the temperature sensor 70 (the temperature of the liquid crystal panel) is in a relatively low temperature region, A lookup table for correcting fluctuations in VT characteristics that occur when the temperature detected by the temperature sensor 70 (temperature of the liquid crystal panel) is in a relatively high temperature region is stored separately.
That is, the control unit 90 has a look-up table that can correct each variation in VT characteristics that varies depending on the temperature range of the liquid crystal panel.

  Based on such a configuration, the control unit 90 refers to a table selected from a plurality of look-up tables based on the detection result of the temperature sensor 70 (temperature of the liquid crystal panel 400G), whereby each liquid crystal panel 400R, 400G and 400B are controlled.

  Further, the projector 1 of the present embodiment can display an image in a plurality of color modes. Here, the color mode is a mode for adjusting the hue of the projected image in accordance with the application of the viewer.

  The projector 1 corresponds to three color modes, for example, a standard color mode, a luminance priority color mode, and a color priority color mode. The standard color mode is a mode that displays an image in which the balance of brightness and hue is evenly adjusted, and the brightness priority color mode is a mode that displays an image adjusted by giving priority to brightness over hue, and color priority. The color mode is a mode for displaying an image adjusted by giving priority to the hue over the luminance.

  In the projector 1, the driving conditions (transmittance, etc.) of the liquid crystal panels 400R, 400G, 400B are different for each color mode. The control unit 90 stores a lookup table corresponding to each color mode.

  Based on such a configuration, the control unit 90 controls the liquid crystal panels 400R, 400G, and 400B by referring to a lookup table corresponding to the color mode.

FIG. 3 is a diagram conceptually showing a lookup table stored in the control unit 90.
As shown in FIG. 3, the control unit 90 of the present embodiment stores, for example, six lookup tables TB1 to TB6 (hereinafter simply referred to as tables TB1 to TB6).

  The tables TB1 and TB2 correspond to the standard color mode, the tables TB3 and TB4 correspond to the luminance priority color mode, and the tables TB5 and TB6 correspond to the color priority color mode.

That is, when the standard color mode is selected, the control unit 90 selects one of the tables TB1 and TB2 based on the detection result of the temperature sensor 70.
The table TB1 is a table selected by the control unit 90 when the detection result of the temperature sensor 70 is lower than a predetermined threshold (usually when the lighting device 100 is driven in the power saving mode).
The table TB2 is a table selected by the control unit 90 when the detection result of the temperature sensor 70 is higher than a predetermined threshold (usually when the lighting device 100 is driven in the steady power mode).

When the luminance priority mode is selected, the control unit 90 selects one of the tables TB3 and TB4 based on the detection result of the temperature sensor 70.
The table TB3 is a table selected by the control unit 90 when the detection result of the temperature sensor 70 is lower than a predetermined threshold (usually when the lighting device 100 is driven in the power saving mode).
The table TB4 is a table selected by the control unit 90 when the detection result of the temperature sensor 70 is higher than a predetermined threshold (usually when the lighting device 100 is driven in the rated power mode).

When the color priority mode is selected, the control unit 90 selects one of the tables TB5 and TB6 based on the detection result of the temperature sensor 70.
The table TB5 is a table selected by the control unit 90 when the detection result of the temperature sensor 70 is lower than a predetermined threshold (usually when the lighting device 100 is driven in the power saving mode).
The table TB6 is a table selected by the control unit 90 when the detection result of the temperature sensor 70 is higher than a predetermined threshold (usually when the lighting device 100 is driven in the rated power mode).

  Next, an example of the operation of the projector 1 according to this embodiment will be described. In this description, a case where the projector 1 adopts the standard mode as the color mode will be described.

  When performing image display, the projector 1 according to the present embodiment controls the driving of the liquid crystal panels 400R, 400G, and 400B by referring to a table selected based on the detection result of the temperature sensor 70.

  Specifically, the control unit 90 compares the detection result of the temperature sensor 70 with a predetermined threshold value. When the detection result of the temperature sensor 70 is lower than the predetermined threshold, the control unit 90 selects the table TB1 and controls the driving of the liquid crystal panels 400R, 400G, and 400B by referring to the table TB1. On the other hand, when the detection result of the temperature sensor 70 is higher than the predetermined threshold, the control unit 90 selects the table TB2 and controls the driving of the liquid crystal panels 400R, 400G, and 400B by referring to the table TB2.

During the operation of the projector 1, the control unit 90 continues to compare the detection result of the temperature sensor 70 with a predetermined threshold value. Then, one of the tables TB1 and TB2 used for driving the liquid crystal panels 400R, 400G, and 400B is selected according to the comparison result.
As described above, according to the projector 1 of the present embodiment, since the optimum lookup table is selected based on the detection result of the temperature sensor 70, each of the liquid crystal panels 400R, 400G, It is possible to satisfactorily correct the variation in the VT characteristic that occurs at 400B, and to suppress degradation in the quality of the display image.

Even when the projector 1 is driven under the same conditions, the temperature of the liquid crystal panels 400R, 400G, and 400B varies depending on the external environment (external temperature, humidity, etc.) of the projector 1. That is, even when driving in the power saving mode, when the outside air temperature is high, the temperature of the liquid crystal panel may be increased. Similarly, even when driving in the rated power mode, it is assumed that the temperature of the liquid crystal panel is lowered when the outside air temperature is low.
Therefore, when a table is selected according to the power mode, a desired table is not selected depending on the outside air temperature, and there is a possibility that the variation in the VT characteristic generated in the liquid crystal panel cannot be corrected well.

  On the other hand, according to the present embodiment, the optimum look-up table is selected by paying attention only to the temperatures of the liquid crystal panels 400R, 400G, and 400B. Even in the case of driving at a high quality, it is possible to display a high-quality image by satisfactorily correcting the variation of the VT characteristic generated in the liquid crystal panel.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the illumination device 100 is exemplified to generate the illumination light WL using the semiconductor laser 30a and the phosphor layer 11, but the present invention is not limited to this, and a discharge lamp such as an ultra-high pressure mercury lamp. May be used as a lighting device.

  In the above embodiment, the temperature sensor 70 is provided in the liquid crystal panel 400G as an example. However, the temperature sensor 70 may be provided in either the liquid crystal panel 400R or the liquid crystal panel 400B.

Further, in the projector 1, for example, when a state in which a video signal is not input to the liquid crystal panel for a predetermined time in a power-on state continues, the lighting device 100 may be automatically switched from the rated power mode to the power saving mode. In this way, standby power in the projector 1 can be reduced, so that further energy saving can be achieved.
Further, the color mode and the driving mode (rated power mode or power saving mode) of the lighting device 100 may be switched according to the external environment (outside temperature, humidity, brightness, etc.).

  Moreover, although the example of the illuminating device provided with the transmissive | pervious phosphor wheel was given in the said embodiment, the illuminating device provided with the reflective phosphor wheel may be sufficient.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 100 ... Illuminating device, 200 ... Color separation optical system, 400R, 400G, 400B ... Liquid crystal panel, TB1, TB2, TB3, TB, 4, TB5, TB6 ... Table (lookup table), WL ... Illumination light .

Claims (4)

A lighting device;
A color separation optical system for color-separating illumination light from the illumination device;
A plurality of liquid crystal panels arranged corresponding to the respective colors separated by the color separation optical system;
A plurality of look-up tables storing data relating to drive voltage, and a control unit for controlling the plurality of liquid crystal panels by referring to a table selected from the plurality of look-up tables;
One temperature sensor provided in any of the plurality of liquid crystal panels,
The control unit selects the look-up table used for controlling the plurality of liquid crystal panels based on a detection result of the temperature sensor. The color separation optical system separates the white illumination light emitted from the illumination device into red, blue and green light,
The projector according to claim 1, wherein the temperature sensor is provided in the liquid crystal panel arranged corresponding to the green light. The projector according to claim 1, wherein the lighting device includes a solid light source and a wavelength conversion element on which light emitted from the solid light source is incident. 4. The lighting device is driven in either a rated power mode or a power saving mode in which a lower voltage is applied to the liquid crystal panel than in the rated power mode. 5. The projector described.

Images