JP2017097153A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector capable of performing desired lighting control, even when the maximum rating on output is changed by a use environment.SOLUTION: The projector includes laser light sources 103 to 105 which output a laser beam, sensors 119 to 121 which detect the temperatures of the laser light sources 103 to 105, a light reduction part 112 which reduces and transmits the laser beam outputted by the laser light sources 103 to 105, and a control part 101 which controls the output of the laser light sources 103 to 105 and the transmittance of the light reduction part 112. The control part 101 performs dimming control for changing the output of the laser light sources 103 to 105 when a predetermined light quantity is outputted and the transmittance of the light reduction part 112, according to the temperatures of the laser light sources 103 to 105 detected by the sensors 119 to 121.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a projector, and more particularly to a projector used for a head-up display device or the like.

  There is a projector that scans a laser beam and projects an image (see, for example, Patent Document 1). Patent Document 1 discloses a technique that can quickly obtain an image with stable display luminance even if the light intensity characteristic of a laser light source changes depending on the use environment or the like.

JP 2014-74818 A

  In Patent Document 1, the light intensity characteristic of a laser light source that changes depending on the usage environment is calculated from the light intensity of the laser light detected by the light detection means and used to change the light transmittance of the laser light at the light control unit. To perform desired dimming.

  However, Patent Document 1 does not take into consideration that the rating (hereinafter referred to as the maximum rated output) regarding the output (power) of the laser light source also changes depending on the use environment. The maximum rated output of the laser light source is a maximum output value that can be output so as not to cause deterioration or destruction of the laser light source in the usage environment. Therefore, for example, when the temperature as the use environment is high and the maximum rated output of the laser light source is reduced, that is, when the maximum output of the laser light source is limited, the projector disclosed in Patent Document 1 calculates the calculated light In some cases, laser light cannot be output according to the intensity characteristics, and desired light control cannot be performed.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a projector capable of performing desired dimming even when the output rating changes depending on the use environment.

  In order to achieve the above object, a projector according to an aspect of the present invention includes a laser light source unit that outputs laser light, a sensor that detects a temperature of the laser light source unit, and laser light output by the laser light source unit. And a controller for controlling the output of the laser light source unit and the transmittance of the dimming unit, and the control unit is detected by the sensor. Dimming control is performed to change the output of the laser light source unit and the transmittance of the dimming unit when outputting a predetermined amount of light according to the temperature of the laser light source unit.

  According to this, the laser light source output and the light attenuation rate can be adjusted in accordance with the temperature of the laser light source, and desired light control can be performed even when the output changes depending on the use environment.

  For example, according to the temperature of the laser light source unit detected by the sensor, the control unit outputs the laser light source unit so that the maximum output of the laser light source unit at the temperature is equal to or lower than a rating at the temperature. In addition, the light control may be performed by controlling the transmittance of the dimming unit.

  According to this, even when the maximum rated output changes due to temperature change, not only the output of the laser light source is controlled at the maximum output below the maximum rated output, but also according to the output of the laser light source below the changed maximum rated output. To control the transmittance of the dimming part. Thereby, laser light can be irradiated with the same dimming ratio as that at room temperature. In this way, even when the maximum rated output regarding the output changes depending on the use environment, desired dimming can be performed.

  For example, when the temperature of the laser light source unit detected by the sensor is higher than normal temperature, the control unit is configured to reduce the laser light source unit so that the temperature is equal to or lower than the rating of the laser light source unit at the detected temperature. It is also possible to perform control to reduce the maximum output of the part and increase the transmittance of the dimming part.

  According to this, even when the maximum rated output is reduced due to a temperature change, desired dimming can be performed.

  Further, the laser light source unit includes a plurality of light sources that respectively output laser beams of different color components, and the control unit includes the plurality of light sources that constitute white balance with the rated outputs of the plurality of light sources. Based on the output of the light source, one of the plurality of light sources is selected, and the maximum output of the selected one light source is rated at the temperature of the one light source detected by the sensor. The other light source is controlled such that the maximum output of the one light source is controlled, and the maximum output of the other light source other than the one light source is smaller than the rated value at the temperature of the other light source detected by the sensor. The maximum output may be controlled.

  According to this, even when the maximum rated output changes due to temperature change, it is possible to perform desired dimming in consideration of white balance.

  Further, the control unit selects, as the one light source, a first light source having a maximum value of a ratio of a rated output at each temperature to an output constituting white balance at each temperature among the plurality of light sources. You may do it.

  According to this, even when the maximum rated output changes due to temperature change, it is possible to output with maximum brightness at the temperature at that time while maintaining white balance.

  Here, for example, the laser beam output from the first light source is a green component laser beam.

  The control unit may further maintain a desired transmittance by changing a driving voltage for driving the dimming unit according to the temperature of the dimming unit.

  According to this, even when the transmittance of the liquid crystal element constituting the light reducing portion varies due to a temperature change, it is possible to change the driving voltage to be applied so that the transmittance according to the temperature of the liquid crystal element. Regardless of the temperature of the liquid crystal element, the transmittance of the dimming portion can be controlled with high accuracy.

  Furthermore, it has a table showing the relationship between the drive voltage and the transmittance at each of the plurality of temperatures of the dimming unit, the control unit using the table according to the temperature of the dimming unit The drive voltage may be changed.

  According to this, the drive voltage to be applied can be changed using a table prepared in advance so that the transmittance according to the temperature of the liquid crystal element is obtained.

  The present invention can be realized not only as a projector, but also as a control method using steps executed by characteristic processing units included in the projector. Further, it can be realized as a program for causing a computer to execute a characteristic step included in a program for causing a computer to function as a characteristic processing unit included in a projector or a control method. Such a program can be distributed via a computer-readable non-transitory recording medium such as a CD-ROM (Compact Disc-Read Only Memory) or a communication network such as the Internet. Yes.

  According to the projector of the present invention, desired dimming can be performed even when the maximum rated output changes depending on the use environment.

It is a figure which shows the example of installation of the HUD apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the scenery which a user sees through a windshield. 1 is a block diagram illustrating an example of a configuration of a HUD device according to a first embodiment. 6 is a diagram illustrating an example of a configuration of a light reduction unit according to Embodiment 1. FIG. It is a figure which shows the relationship between the temperature of the laser light source which concerns on Embodiment 1, and a maximum rated output. It is a figure which shows the relationship between the light reduction ratio of each device in the normal temperature which concerns on Embodiment 1, and a light control ratio. It is a figure which shows the relationship between the dimming ratio of each device in the high temperature which concerns on Embodiment 1, and a light control ratio. 6 is a diagram illustrating an example of an operation at a high temperature of the projector according to Embodiment 1. FIG. 6 is a diagram illustrating an example of an operation at a high temperature of the projector according to Embodiment 1. FIG. 6 is a flowchart for explaining a characteristic operation of the projector according to the first embodiment. It is an example of the graph which plotted the output value of the laser light source used as a white balance ratio for every temperature. It is an example of the graph which shows the value which divided the output value used as white balance by the maximum output value of a rating for every temperature. It is a figure which shows the numerical example at the time of selecting the laser beam source of G shown in FIG. 11, and determining a light reduction ratio. 10 is a diagram illustrating an example of a configuration of a light reduction unit according to Embodiment 3. FIG. It is a figure which shows an example of the characteristic of the liquid crystal element which comprises a light reduction part. It is a figure which shows an example of the relationship between the drive voltage for every temperature and the transmittance | permeability in the light reduction part shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims are described as arbitrary constituent elements.

(Embodiment 1)
Hereinafter, the projector of the present invention will be described by taking a head-up display (hereinafter referred to as HUD) device as an example. The HUD device is a system that projects an image on the windshield of an automobile, projects a virtual image on the tip of the windshield (outside the vehicle), and projects the image in the field of view of the user (driver).

<Overall configuration>
FIG. 1 is a diagram showing an installation example of the HUD device according to Embodiment 1 of the present invention. As shown in FIG. 1, the HUD device 1 includes a projector 10 and a combiner 60 (which constitutes a transparent display board).

  The projector 10 is installed in a transportation device such as the automobile 50, and is installed on the dashboard of the automobile 50, for example. The combiner 60 is a display surface installed on a part of the windshield 20 of the automobile 50. The projector 10 projects an image on the combiner 60 by irradiating the combiner 60 with light. Since the combiner 60 is composed of a polarizing element, a wavelength selection element, a half mirror, and the like, the image projected by the projector 10 is superimposed and displayed on the scenery outside the vehicle. Note that the windshield 20 itself may have the function of the combiner 60 in some cases.

  FIG. 2 is a diagram illustrating an example of a landscape viewed by the user through the windshield. As described above, the combiner 60 is installed on the windshield 20. The image projected from the projector 10 is displayed on the combiner 60. As shown in FIG. 2, the projector 10 has a function of displaying information related to car navigation (for example, route information to a destination) and information related to a car (for example, fuel efficiency information) on the combiner 60. For example, the projector 10 displays route information 61 (“Osaka”, “Kobe” and “arrows” indicating the corresponding routes) to the destination, and distance information 62 (“1.0 km”) to the destination. The displayed image (an example of a content image) is displayed on the combiner 60. As shown in FIG. 2, since the image projected from the projector 10 is displayed in the front landscape, the user can acquire information useful for driving without diverting the line of sight while driving the automobile 50.

  FIG. 3 is a block diagram showing an example of the configuration of the HUD device according to the first embodiment. FIG. 4 is a diagram illustrating an example of the configuration of the dimming unit according to the first embodiment. FIG. 5 is a diagram showing the relationship between the temperature of the laser light source according to Embodiment 1 and the maximum rated output.

  The projector 10 is a projector that displays an image by irradiating a laser beam, and includes a control unit 101, laser light sources 103 to 105, beam splitters 106 to 109, a detection unit 110, and a light reduction unit 112. , MEMS mirror 114, LD-APC 117, LD driver 118, and sensors 119-121.

  The control unit 101 controls each unit of the projector 10. The control unit 101 outputs the output of the laser light sources 103 to 105 and the transmittance of the dimming unit 112 when outputting a predetermined amount of light according to the temperatures of the laser light sources 103 to 105 detected by the sensors 119 to 121. Perform dimming control to change. In the present embodiment, the control unit 101 controls the outputs of the laser light sources 103 to 105 and the transmittance of the dimming unit 112. For example, when a dimming instruction is input from the outside of the projector 10, for example, by a user or the like, the control unit 101 acquires the dimming ratio information included in the instruction, and the dimming ratio (( The control signal is output to the LD-APC 117 and the dimming unit 112 so that the total dimming ratio is obtained.

  In addition, the control unit 101 acquires the temperatures (temperature information) of the laser light sources 103 to 105 detected by the sensors 119 to 121. The control unit 101 outputs a control signal indicating a target output equal to or lower than the maximum rated output of the laser light sources 103 to 105 to the LD-APC 117 according to the acquired temperature information, and a drive voltage that changes the transmittance of the dimming unit 112. Is output to the dimming unit 112 as a control signal.

  More specifically, in accordance with the temperature of the laser light sources 103 to 105 detected by the sensors 119 to 121, the control unit 101 controls the laser so that the maximum output of the laser light sources 103 to 105 at the temperature is below the rating. The output of the light sources 103 to 105 is controlled, and the transmittance of the light reduction unit 112 is controlled so as to be substantially the same as the dimming ratio at room temperature. For example, when the temperature of the laser light sources 103 to 105 detected by the sensors 119 to 121 is higher than the normal temperature, the control unit 101 causes the laser light sources 103 to 105 to be equal to or lower than the rated temperatures at the detected temperatures. Control is performed to increase the transmittance of the light reduction unit 112 so that the maximum output of the laser light sources 103 to 105 is reduced and the light control ratio is substantially the same as the light control ratio at room temperature.

  Each of the laser light sources 103 to 105 is a light source that outputs laser light having a plurality of different color components. More specifically, the laser light source 103 is a laser diode that reflects blue laser light so as to be coaxial with other colors by the beam splitter 106 and is input to the light reduction unit 112. The laser light source 104 is a laser diode that reflects green laser light so as to be coaxial with other colors by the beam splitter 107 and is input to the light reduction unit 112. The laser light source 105 is a laser diode that reflects red laser light so as to be coaxial with other colors by the beam splitter 108 and is input to the light reduction unit 112. A group of the laser light sources 103 to 105 corresponds to a laser light source unit that outputs laser light, and may be hereinafter referred to as an RGB laser light source.

  In addition, as shown in FIG. 5, the maximum rated output of each of the laser light sources 103 to 105 changes according to the temperature. For example, as indicated by LD-B in FIG. 5, the maximum rated output of the laser light source 103 that outputs a blue component laser light is 100 mW at −20 degrees to 90 degrees. For example, as shown by LD-G in FIG. 5, the maximum rated output of the laser light source 104 that outputs the green component laser light is 100 mW at 10 degrees to 40 degrees, and a high temperature of 40 degrees or more or 10 At the following low temperature, it is lower than 100 mW. Similarly, for example, as indicated by LD-R in FIG. 5, the maximum rated output of the laser light source 105 that outputs the red component laser light is 500 mW in the vicinity of −10 to 55 degrees, and is a high temperature of 50 degrees or more. Then, it becomes lower than 500 mW.

  The detection unit 110 is, for example, a photodiode, and detects the amount of laser light output from each of the laser light sources 103 to 105 partially reflected by the beam splitter 109.

  The dimming unit 112 is controlled by the control unit 101 and attenuates and transmits the laser light output from the laser light sources 103 to 105. The light reduction unit 112 is disposed at a position after the laser beams output from the laser light sources 103 to 105 are merged (combined) by the beam splitters 106 to 108. The dimming unit 112 is disposed on the optical path of the laser light output from the laser light sources 103 to 105. In the present embodiment, as shown in FIG. 4, the dimming unit 112 includes a liquid crystal attenuator (LCD-ATT) including a liquid crystal element 1121 and two polarizing plates (a polarizing plate 1122 and a polarizing plate 1123). It is. In the light reduction unit 112, the transmittance of the light reduction unit 112 can be controlled by applying a driving voltage to the liquid crystal element 1121 and changing the alignment of the liquid crystal of the liquid crystal element 1121. The drive voltage applied to the liquid crystal element 1121 is applied to the signal lines Ch1 and Ch2 shown in FIG. 4 as drive signals.

  The MEMS mirror 114 projects an image by directing the laser light that has passed through the dimming unit 112 toward the combiner 60. The MEMS mirror 114 scans the horizontal direction at high speed by resonance driving and scans the vertical direction at low speed by DC driving.

  The LD-APC 117 is a light source control unit that controls the LD driver 118 based on the control by the control unit 101 to control the irradiation of the laser light from the laser light sources 103 to 105. Specifically, the LD-APC 117 performs control for irradiating the laser light sources 103 to 105 with the color component laser light corresponding to each pixel of the image in accordance with the scanning timing of the image by the MEMS mirror 114. The LD-APC 117 performs control to irradiate the laser light sources 103 to 105 with the target output instructed by the control unit 101 with reference to the amount of laser light detected by the detection unit 110.

  The LD driver 118 adjusts the light amounts of the laser light sources 103 to 105 by supplying a drive current to the laser light sources 103 to 105.

  The sensors 119 to 121 are temperature sensors that detect the temperatures of the laser light sources 103 to 105. The sensors 119 to 121 are composed of, for example, a thermistor.

<Projector operation>
Next, the operation of the projector 10 will be described. Hereinafter, a characteristic operation among the operations of the projector 10 will be mainly described.

  FIG. 6 is a diagram showing the relationship between the dimming ratio and the dimming ratio (total dimming ratio) of each device at room temperature according to the first embodiment. FIG. 7 is a diagram showing the relationship between the dimming ratio and the dimming ratio (total dimming ratio) of each device at a high temperature according to the first embodiment. Here, the vertical axis represents the dimming ratio of the dimming unit 112 and the dimming ratio of the output of the laser light source (total output of the three laser light sources), and the horizontal axis represents the dimming ratio (total dimming ratio). Show. The case where the dimming ratio of the dimming unit 112 is 1 means that the transmittance of the dimming unit 112 is 1, and the dimming unit 112 does not dimm the light. Further, the output of the laser light source being 1 means a rating relating to the output at room temperature, that is, the maximum output (maximum rated output) that the laser light source can output.

  The control unit 101 refers to a table describing the relationship shown in FIG. This table may be stored in a memory (not shown) of the control unit 101, or may be stored in a memory (not shown) of the projector 10. When the control unit 101 acquires the dimming ratio information, the control unit 101 refers to the table in which the relationship illustrated in FIG. 6 is described so that the dimming ratio (total dimming ratio) indicated by the acquired dimming ratio information is obtained. Determine power and transmittance. And the control part 101 outputs the control signal for controlling so that it may become the determined target output and transmittance | permeability to the light reduction part 112 and the laser light source, and the output which passed the light reduction part 112 of the laser light source Is controlled to be a dimming ratio (total dimming ratio). Here, the reason why the output of the laser light source is in a saw-tooth shape is that the transmittance of the light reducing unit 112 is controlled so as to change in a step shape instead of a continuous shape.

  However, the maximum rated output of the laser light source varies depending on the temperature, as shown in FIG. For example, when the laser light source becomes a low temperature of, for example, 10 degrees or less or a high temperature of, for example, 50 degrees or more, the maximum output value that can be output by the maximum rated output is lowered. That is, when the temperature of the laser light source is changed to a temperature different from the normal temperature, the dimming ratio (total dimming ratio) indicated by the dimming ratio information is calculated using the table in which the relationship shown in FIG. 6 is described. Cannot be realized.

  Therefore, in the present embodiment, the control unit 101 acquires the temperatures (temperature information) of the laser light sources 103 to 105 from the sensors 119 to 121, and the temperature of the laser light sources 103 to 105 is a high temperature or a low temperature different from the normal temperature. If it is determined, the maximum output of the laser light sources 103 to 105 is lowered so that the maximum output of the laser light sources 103 to 105 at the high temperature or low temperature is equal to or less than the maximum rated output. That is, as shown in FIG. 7, the control unit 101 controls the output of the laser light source (the value of the dimming ratio) to be small, and increases the value of the dimming ratio of the dimming unit 112 (changes the transmittance). Control it so that a lot of light is transmitted. In this way, the control unit 101 sets the dimming ratio (total dimming ratio) to the dimming ratio (total dimming ratio) at room temperature even when the temperature of the laser light sources 103 to 105 is high or low. ).

  It should be noted that a table describing the relationship shown in FIG. 7 may be stored for each temperature in a memory (not shown) of the control unit 101 or the projector 10. Here, in FIG. 7, as described above, the laser light sources 103 to 105 are at a high temperature or a low temperature different from the normal temperature, and the laser light sources 103 to 105 have a maximum output equal to or lower than the maximum rated output. When it is necessary to reduce the maximum output of the light sources 103 to 105, the control unit 101 controls the output of the laser light source (the value of the dimming ratio) to be small, and sets the value of the dimming ratio of the dimming unit 112. A relationship is shown in which control is performed so that a large amount of light is transmitted (by increasing the transmittance). Thereby, when it is necessary to reduce the maximum output of the laser light sources 103 to 105 so that the maximum output of the laser light sources 103 to 105 is less than the maximum rated output, the dimming ratio (total dimming ratio) is adjusted at room temperature. It can be made substantially the same as the light ratio (total dimming ratio). Further, the control unit 101 may correct and use the values in the table in which the relationship shown in FIG. 6 is described according to the maximum rated output of the laser light source so that the relationship shown in FIG. 7 is obtained. In any case, when a dimming instruction is input from the outside of the projector 10, for example, by a user or the like, the control unit 101 is included in the instruction whether it is at room temperature or not (regardless of the temperature of the laser light source). The outputs of the laser light sources 103 to 105 and the transmittance of the dimming unit 112 are controlled so that the dimming ratio (the dimming ratio) indicated by the dimming ratio information.

  Here, an example of the operation of the projector 10 when the temperature of the laser light sources 103 to 105 is as high as 85 degrees will be described. Below, the normal temperature is set to 25 degrees.

  8A and 8B are diagrams illustrating an example of the operation of the projector 10 according to Embodiment 1 at a high temperature.

  FIG. 8A shows that, for example, when the maximum rated output of the laser light source at room temperature of 25 degrees is 1, the maximum rated output of the laser light source at high temperature of 85 degrees is 0.5. The maximum rated output of the laser light source for each temperature is determined by the characteristics of the laser light source and is a specification value of the laser light source. The numerical values shown in FIG. 8A are numerical values for ease of explanation and are examples.

  On the other hand, in FIG. 8B, the value of the dimming ratio of the dimming unit 112 for obtaining the dimming ratio (dimming ratio) required at normal temperature (25 degrees) and high temperature (85 degrees) and the maximum output of the laser light source. Values are shown.

  That is, the dimming ratio of the dimming unit 112 is 2 at a high temperature (85 degrees) compared to normal temperature (25 degrees) as shown in FIG. 8B so that the required dimming ratio (dimming ratio) is obtained. It has doubled. Further, as shown in FIG. 8B, the output value used in the laser light source is halved at a high temperature (85 degrees) compared to the normal temperature (25 degrees), and is less than the maximum rated output at the high temperature (85 degrees). It has become.

  In addition, it was requested | required that the dimming ratio of the dimming part 112 was the same by the required dimming ratio 1-0.5 and 0.5-0.25 in high temperature (85 degree | times). This is because the dimming ratio of the dimming unit 112 is maximized (saturated) at the dimming ratio of 0.5 to 1.

  FIG. 9 is a flowchart for explaining a characteristic operation of the projector according to the first embodiment.

  First, the control unit 101 acquires temperature information of the laser light sources 103 to 105 (S101).

  Next, the control unit 101 determines whether or not the acquired temperature information indicates normal temperature (S102). If the acquired temperature information does not indicate normal temperature (No in S102), the control unit 101 follows the maximum rated output corresponding to the acquired temperature information. The maximum output of the laser light sources 103 to 105 is controlled (S103). Then, the control unit 101 controls the transmittance of the dimming unit 112 (S104). When the acquired temperature information indicates normal temperature (Yes in S102), the process returns to S101.

<Effect>
In this manner, in the projector 10 of the present embodiment, the laser beams output from the laser light sources 103 to 105 are combined and then attenuated when passing through the dimming unit 112 and scanned by the MEMS mirror 114. It is projected onto a screen such as a combiner 60. Further, when the projector 10 according to the present embodiment acquires the dimming ratio information by a user or the like, the transmittance of the dimming unit 112 and the laser so that the dimming ratio (the dimming ratio) indicated by the dimming ratio information is obtained. Control the output of the light source.

  According to the projector 10 of the present embodiment, even when the maximum rated output changes due to a temperature change, not only the output of the laser light source is controlled with the maximum output below the maximum rated output but also the changed maximum rated output or below. The transmittance of the light reducing unit is controlled according to the output of the laser light source. Thereby, laser light can be irradiated with the same dimming ratio as that at room temperature.

  For example, the projector 10 according to the present embodiment detects the temperature of the laser light source, and when the detected temperature is increased, the projector 10 controls to reduce the maximum output of the laser light source and control the transmittance of the light reduction unit. By shifting, the amount of light (dimming ratio) is adjusted to cover changes due to temperature. In this way, a desired dimming rate (dimming) can be realized regardless of the temperature of the laser light source.

(Embodiment 2)
In the first embodiment, it has been described that the outputs of the laser light sources 103 to 105 are controlled in consideration of the rating relating to the output that varies depending on the temperature. However, as shown in FIG. 5, the maximum rated output not only changes depending on the temperature, but also differs for each of the laser light sources 103 to 105 (laser light sources that emit color component laser light) even at the same temperature. Further, the wavelengths of the laser light sources 103 to 105 also vary with temperature. Hereinafter, it will be described that desired light control can be performed regardless of the temperature of the laser light source even when these are taken into consideration.

  FIG. 10 is an example of a graph in which the output value of the laser light source serving as the white balance ratio is plotted for each temperature. FIG. 10 shows a graph in the case where the rated output at 25 degrees of the laser light source remains constant at any temperature.

  As shown in FIG. 10, the output value of the laser light source, which is the white balance ratio, varies with temperature. This is because the wavelength of the RGB laser light source changes depending on the temperature, and the output ratio of the RGB laser light source that becomes white balance changes.

  For the projector of the present invention, it is desirable to maintain white balance and maximize the maximum output luminance as much as possible. Therefore, in the present embodiment, the amount by which the maximum output of the laser light source is reduced (dimming rate) is determined in consideration of both the rated maximum output value at that temperature and the output value for white balance. That is, for each of the RGB laser light sources, for each temperature, a value obtained by calculating a value (white balance power value / rated power value) obtained by dividing a white balance output value by a rated maximum output value. The dimming rate is determined according to the largest laser light source.

  FIG. 11 is an example of a graph showing a value obtained by dividing the output value for white balance by the rated maximum output value for each temperature. More specifically, FIG. 11 shows a graph of values obtained by dividing the rated maximum output value shown in FIG. 5 for each temperature by the output value for white balance shown in FIG. 10 for each temperature. ing. In FIG. 11, since the value of the G laser light source (laser light source that outputs green component laser light) is the highest at all temperatures, the maximum rated output of the G laser light source has the least margin. That is, when the dimming ratios of all laser light sources are determined in accordance with the RB laser light sources (laser light sources that output red and blue component laser light) as other laser light sources, the maximum rated output of the G laser light source There is a risk of exceeding. Therefore, the G laser light source is selected from FIG. 11, and the dimming ratio of the RB laser light source is determined in accordance with the G laser light source. Since the maximum rated output and wavelength differ depending on the laser light source used, the graph shown in FIG. 11 is not always obtained. In that case, it is not necessary to determine the attenuation rate of the laser light source of the other color component (RG) in accordance with the G laser light source at all temperatures. The dimming ratio may be determined according to the laser light source.

  FIG. 12 is a diagram showing a numerical example when the G laser source shown in FIG. 11 is selected and the light reduction ratio is determined. As shown in FIG. 12, the dimming ratio of the selected G laser light source is 1 / (white balance power value / rated power value) of the selected G laser light source at each temperature. The dimming ratio of the laser light source of other color components (RB) is calculated from the maximum rated output of the G laser light source at each temperature. Specifically, the dimming ratio (numerical value) of the laser light source of other color components (RB) is calculated from the output value when white balance is constituted by the maximum rated output of the G laser light source at each temperature.

  The numerical values and the like shown in FIG. 12 may be held in a memory (not shown) of the projector 10 or the control unit 101 as a look-up table format or an approximate expression coefficient value.

  Therefore, in the present embodiment, the control unit 101 selects one of the laser light sources 103 to 105 based on the maximum rated output of the laser light sources 103 to 105 and the output of the laser light sources 103 to 105 that constitute the white balance. One laser light source is selected, and the maximum output of the one laser light source is controlled so that the maximum output of the selected one laser light source becomes the maximum rating at the temperature of the one laser light source detected by the sensor. The maximum output of the other laser light source may be controlled so that the maximum output of the other laser light source other than the laser light source is smaller than the maximum rating at the temperature of the other laser light source detected by the sensor.

  In addition, the control unit 101 selects a laser light source (first light source) having a maximum value of the ratio of the maximum rated output to the output constituting the white balance at each temperature among the plurality of laser light sources. Choose as. Here, the laser light source serving as the first light source is a laser light source 104 that outputs green component laser light.

<Effect>
As described above, according to the projector 10 of the present embodiment, even when the maximum rated output changes due to a temperature change, it is possible to output with the maximum luminance at the temperature at that time while maintaining the white balance. Further, according to the projector 10 of the present embodiment, since the output of the laser light source can be determined in consideration of the white balance and the maximum rated output, it is possible to perform desired dimming with good hue.

  As described above, according to the projector 10 of the present embodiment, the output of the laser light source can be controlled with the maximum output below the rating for maintaining the white balance so that the maximum brightness is obtained at the temperature at that time. The laser light can be irradiated at the same dimming ratio as that in the above.

(Embodiment 3)
The transmittance of the liquid crystal element that constitutes the light reducing portion also changes slightly depending on the temperature change. Embodiment 3 will explain this case.

  The projector 10 of the third embodiment is different from the projectors 10 of the first and second embodiments in the configuration of a control unit 101a (not shown) and a dimming unit 112a.

  The control unit 101a has the functions described in the first and second embodiments. Further, the control unit 101a further maintains a desired transmittance by changing a driving voltage for driving the dimming unit 112a according to the temperature of the dimming unit 112a. Note that the projector 10 according to the present embodiment may further include a table indicating the relationship between the driving voltage and the transmittance at each of the plurality of temperatures of the dimming unit 112a. In this case, the control part 101a should just change a drive voltage according to the temperature of the light reduction part 112a using the said table.

  FIG. 13 is a diagram illustrating an example of the configuration of the dimming unit according to the third embodiment. Elements similar to those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. The dimming unit 112a shown in FIG. 13 differs from the dimming unit 112 shown in FIG. 4 in that a temperature sensor 1124 is added.

  FIG. 14 is a diagram illustrating an example of the characteristics of the liquid crystal element constituting the light reduction unit. FIG. 15 is a diagram illustrating an example of the relationship between the drive voltage and the transmittance for each temperature in the light reduction unit illustrated in FIG.

  In the first and second embodiments, the drive voltage (drive signal) applied to the liquid crystal element 1121 constituting the light reduction unit 112 is changed in order to change the transmittance of the light reduction unit 112. However, the transmittance of the liquid crystal element 1121 has temperature characteristics as shown in FIGS. Therefore, in order to make the liquid crystal element 1121 have a desired transmittance, it is necessary to change the driving voltage for each temperature.

  Therefore, the dimming unit 112a of the present embodiment includes a temperature sensor 1124 in the vicinity of the liquid crystal element 1121, as shown in FIG.

  The temperature sensor 1124 detects the temperature of the liquid crystal element 1121. The control unit 101a determines a drive voltage (drive signal) to be applied to ch1-ch2 so that the liquid crystal element 1121 has a desired transmittance according to the temperature detected by the temperature sensor 1124. For example, the control unit 101a determines a drive voltage corresponding to the temperature using, for example, a table as shown in FIG. Note that the table shown in FIG. 15 is measured in advance, for example, when the projector 10 is shipped, and may be stored in a memory (not shown) of the projector 10 or the control unit 101a.

<Effect>
As described above, according to the projector 10 of the present embodiment, even when the transmittance of the liquid crystal element constituting the light reduction unit varies due to the temperature change, the application is performed so that the transmittance according to the temperature of the liquid crystal element is obtained. The driving voltage to be changed can be changed. Thereby, the projector 10 according to the present embodiment can accurately control the transmittance of the dimming unit regardless of the temperature of the liquid crystal element.

(Other embodiments)
Although the HUD device according to the embodiment of the present invention has been described above, the present invention is not limited to this embodiment.

  For example, in the projector 10 described above, the control unit 101 and the LD-APC 117 are specifically configured as a computer system including a microprocessor, a ROM, a RAM, a hard disk drive, a display unit, a keyboard, a mouse, and the like. Also good. A computer program is stored in the RAM or hard disk drive. These processing units achieve their functions by the microprocessor operating according to the computer program. Here, the computer program is configured by combining a plurality of instruction codes indicating instructions for the computer in order to achieve a predetermined function.

  Furthermore, some or all of the constituent elements constituting each of the above-described devices may be configured by one system LSI (Large Scale Integration). The system LSI is a super multifunctional LSI manufactured by integrating a plurality of components on one chip, and includes, for example, a computer system including a microprocessor, ROM, RAM, and the like. In this case, a computer program is stored in the ROM. The system LSI achieves its functions by the microprocessor operating according to the computer program.

  Furthermore, some or all of the constituent elements constituting each of the above-described devices may be configured from an IC card that can be attached to and detached from each device or a single module. The IC card or module is a computer system that includes a microprocessor, ROM, RAM, and the like. The IC card or the module may include the super multifunctional LSI described above. The IC card or the module achieves its function by the microprocessor operating according to the computer program. This IC card or this module may have tamper resistance.

  Further, the present invention may be the method described above. In addition, the present invention may be a computer program that realizes these methods by a computer, or may be a digital signal composed of the computer program.

  Furthermore, the present invention provides a non-transitory recording medium capable of reading the computer program or the digital signal by a computer, such as a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, and a BD. (Blu-ray (registered trademark) Disc), or recorded in a semiconductor memory or the like. The digital signal may be recorded on these non-temporary recording media.

  In the present invention, the computer program or the digital signal may be transmitted via an electric communication line, a wireless or wired communication line, a network represented by the Internet, a data broadcast, or the like.

  The present invention may be a computer system including a microprocessor and a memory, wherein the memory stores the computer program, and the microprocessor operates according to the computer program.

  Further, by recording the program or the digital signal on the non-temporary recording medium and transferring it, or transferring the program or the digital signal via the network or the like, It may be implemented by a computer system.

  Furthermore, the above embodiment and the above modification examples may be combined.

  The present invention can be applied as a projector to, for example, a head-up display device mounted on an automobile.

DESCRIPTION OF SYMBOLS 1 HUD apparatus 10 Projector 20 Windshield 50 Car 60 Combiner 61 Route information 62 Distance information 103, 104, 105 Laser light source 106, 107, 108, 109 Beam splitter 110 Detection part 101, 101a Control part 112, 112a Light reduction part 114 MEMS Mirror 118 LD driver 117 LD-APC
119, 120, 121 Sensor 1121 Liquid crystal element 1122, 1123 Polarizing plate 1124 Temperature sensor

Claims (8)

A laser light source for outputting laser light;
A sensor for detecting a temperature of the laser light source unit;
A dimming unit for dimming and transmitting the laser beam output by the laser light source unit;
A control unit that controls the output of the laser light source unit and the transmittance of the dimming unit;
The control unit is a dimming control that changes the output of the laser light source unit and the transmittance of the dimming unit when outputting a predetermined amount of light according to the temperature of the laser light source unit detected by the sensor. I do,
projector. The control unit controls the output of the laser light source unit according to the temperature of the laser light source unit detected by the sensor so that the maximum output of the laser light source unit at the temperature is equal to or lower than a rating at the temperature. And performing the dimming control by controlling the transmittance of the dimming unit,
The projector according to claim 1. When the temperature of the laser light source unit detected by the sensor is higher than the normal temperature, the control unit is configured so that the laser light source unit has a rating equal to or lower than the rating of the laser light source unit at the detected temperature. Control to reduce the maximum output and increase the transmittance of the dimming part,
The projector according to claim 2. The laser light source unit has a plurality of light sources that respectively output laser beams of different color components,
The controller is
Based on the rated output of the plurality of light sources and the output of the plurality of light sources constituting white balance, one of the plurality of light sources is selected,
The maximum output of the one light source is controlled so that the selected maximum output of the one light source is rated at the temperature of the one light source detected by the sensor, and other light sources other than the one light source are controlled. The maximum output of the other light source is controlled such that the maximum output of the other light source is smaller than the rating at the temperature of the other light source detected by the sensor.
The projector according to claim 2 or 3. The control unit selects, as the one light source, a first light source that has a maximum value of a ratio of a rated output at each temperature to an output constituting white balance at each temperature among the plurality of light sources.
The projector according to claim 4. The laser beam output from the first light source is a green component laser beam.
The projector according to claim 5. The control unit further includes:
By changing the driving voltage for driving the dimming unit according to the temperature of the dimming unit, a desired transmittance is maintained.
The projector according to any one of claims 2 to 6. Furthermore, it has a table showing the relationship between the drive voltage and the transmittance at each of a plurality of temperatures of the dimming unit,
The controller is
Using the table, change the drive voltage according to the temperature of the dimming unit,
The projector according to claim 7.

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