JP6201720B2 - Image display device and control device - Google Patents

Description

  The present invention relates to an image display device and a control device that controls the luminance of image display light.

  A vehicle display device called a head-up display is known. The head-up display is a display that displays information superimposed on the scenery outside the vehicle by transmitting light entering from outside the vehicle and reflecting the image projected from the optical unit arranged inside the vehicle to the windshield of the vehicle. Device. A head-up display has recently been attracting attention as a display device for vehicles because a driver who is viewing the scenery outside the vehicle can recognize information on the image projected from the optical unit with almost no change in line of sight or focus. Collecting.

  The brightness of the image display light is adjusted according to changes in the external environment. For example, the structure which adjusts the brightness of image display light by changing the transmittance | permeability of the liquid crystal film provided in the reflective surface of a reflective mirror is mentioned (for example, refer patent document 1).

JP-A-10-963

  The brightness of the scenery outside where the image display light is superimposed varies depending on the external environment, such as in the daytime in fine weather, at night, or in a tunnel. At this time, if the brightness of the image display light to be superimposed on the outside brightness is not balanced, the visibility of the user may be lowered. It is desirable to present it.

  The present invention has been made in view of the above circumstances, and an object thereof is to present image display light with high visibility.

  In order to solve the above problems, an image display device (10) according to an aspect of the present invention includes a light source (231) and an image display element (240) that modulates light from the light source (231) to generate image display light. ), A light control element (250) provided between the light source (231) and the image display element (240) and dimming light from the light source (231) toward the image display element (240), and an image display light And a control unit (50) for controlling the luminance value. The control unit (50) outputs a first drive unit (541) that outputs a signal for driving the light source (231), and a second drive unit (542) that outputs a signal for driving the dimming element (250). ), And a reception unit (510) that receives an input signal for adjusting the luminance of the image display light, and a first drive unit (541) and a second drive unit according to the input signal received by the reception unit (510) A determination unit (520) that determines the operation of (542). When the luminance value of the image display light is equal to or greater than a predetermined threshold, the determination unit (520) uses the second drive unit (542) so that the dimming degree by the dimming element (250) becomes the first dimming amount. And the first drive unit (541) is operated so that the light intensity from the light source (231) corresponds to the luminance value, so that the luminance value of the image display light is less than a predetermined threshold value. In this case, the second driving unit (541) is operated so that the light emission intensity of the light source (231) is constant, and the degree of dimming by the dimming element (250) is larger than the first dimming amount. The second drive unit (542) is operated so as to reduce the amount of light.

  Another aspect of the present invention is a control device (50) for controlling the image display device (10). The control device (50) reduces the light from the first drive unit (541) that outputs a signal for driving the light source (231) and the light source (231) to the image display element (240). A second drive unit (542) that outputs a signal for driving the dimming element (250) to be displaced, and an input signal for determining the luminance value of the image display light modulated by the image display element (240) A reception unit (510), and a determination unit (520) that determines the operation of the first drive unit (541) and the second drive unit (542) according to the input signal received by the reception unit (510). . When the luminance value of the image display light is equal to or greater than a predetermined threshold, the determination unit (520) uses the second drive unit (542) so that the dimming degree by the dimming element (250) becomes the first dimming amount. And the first drive unit (541) is operated so that the light intensity from the light source (231) corresponds to the luminance value, so that the luminance value of the image display light is less than a predetermined threshold value. In this case, the second driving unit (541) is operated so that the light emission intensity of the light source (231) is constant, and the degree of dimming by the dimming element (250) is larger than the first dimming amount. The second drive unit (542) is operated so as to reduce the amount of light.

  According to the image display device or the control device of the present invention, it is possible to provide image display light with high visibility.

It is a figure which shows typically the installation aspect of the head-up display which concerns on embodiment of this invention. It is a figure which shows the internal structure of an image projection part with the optical path of image display light. It is a block diagram which shows the function structure of a control apparatus. It is a figure which shows the example of the brightness | luminance table which a control apparatus hold | maintains. It is a graph which shows the relationship between a brightness | luminance step and a brightness | luminance value. It is a flowchart which shows the flow of operation | movement of a control apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. Specific numerical values and the like shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  As an example of the image display apparatus according to the embodiment, a head-up display 10 installed and used in a dashboard of a vehicle will be described as an example. FIG. 1 is a diagram schematically showing an installation mode of a head-up display 10 according to an embodiment of the present invention. The head-up display 10 includes an optical unit 100 and a control device 50. FIG. 1 is a diagram showing a case where the optical unit 100 is used in a dashboard on the left side with reference to the traveling direction of the vehicle (left direction in FIG. 1). Hereinafter, an outline of the head-up display 10 will be described with reference to FIG.

  The control device 50 includes a CPU (Central Processing Unit) (not shown), and generates an image signal to be displayed on the optical unit 100. The control device 50 also includes an external input interface (not shown), which receives an image signal output from an external device such as a navigation device or a media playback device, and performs a predetermined process on the input signal. Thereafter, it can be output to the optical unit 100.

  The illuminance sensor 60 is provided in the vicinity of the windshield 610 and detects the brightness of outside light and the brightness in the vehicle. The illuminance sensor 60 is connected to the control device 50, and the illuminance value detected by the illuminance sensor 60 is transmitted to the control device 50 and used to determine the luminance of the image display light.

  The optical unit 100 generates image display light to be displayed as a virtual image 450 on the windshield 610 based on the image signal generated by the control device 50. Therefore, the optical unit 100 includes an image projection unit 210, an intermediate mirror 350, an intermediate image formation unit 360, and a projection mirror 400 inside the housing 110.

  The image projection unit 210 houses optical elements such as a light source, an image display element, various optical lenses, and a mirror. The image projection unit 210 generates and projects image display light based on the image signal output from the control device 50. In the present embodiment, a case where LCOS (Liquid crystal on silicon) which is a reflective liquid crystal display panel is used as an image display element is illustrated.

  The image display light projected by the image projection unit 210 is reflected by the intermediate mirror 350. The image display light reflected by the intermediate mirror 350 forms an image on the intermediate image forming unit 360. The image display light related to the real image formed by the intermediate image forming unit 360 is transmitted through the intermediate image forming unit 360 and projected onto the projection mirror 400.

  The intermediate image forming unit 360 includes a diffusion screen 362 and a concave lens 364. The diffusion screen 362 forms a real image based on the image display light transmitted through the intermediate image forming unit 360 and controls the light distribution angle of the image display light toward the projection mirror 400. The concave lens 364 controls the direction of the principal ray of the image display light traveling toward the projection mirror 400 and adjusts the angle formed by the image display light before and after passing through the intermediate image forming unit 360.

  The image display light formed on the intermediate image forming unit 360 is reflected by the projection mirror 400 and projected onto the windshield 610. The projection mirror 400 is a concave mirror, and the image display light formed on the intermediate image forming unit 360 is enlarged by the projection mirror 400 and projected onto the windshield 610. The image display light projected on the windshield 610 is changed to an optical path toward the user by the windshield 610. The user E who is a driver recognizes the image display light reflected by the windshield 610 as a virtual image 450 ahead of the windshield 610 in the line-of-sight direction.

  With the above configuration, the user can visually recognize the virtual image based on the image signal output from the control device 50 by superimposing it on the actual landscape via the windshield 610.

  Next, the image projection unit 210 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram illustrating an internal configuration of the image projection unit 210 together with an optical path of image display light.

  The image projection unit 210 includes a light source 231, a collimating lens 232, a UV-IR (Ultra Violet-Infrared Ray) cut filter 233, a polarizer 234, a fly-eye lens 235, a reflecting mirror 236, a field lens 237, a polarizing beam splitter 238, and so on. A phase difference plate 239, an image display element 240, an analyzer 241, a projection lens 242, a heat sink 243, and a light control element 250 are provided.

  The light source 231 includes a light emitting diode that emits white light, and is attached to the heat sink 243. The light source 231 is driven by a drive current having a pulse waveform based on a control signal from the control device 50. Light emission intensity of the light source 231 is controlled by adjusting the amplitude value and the duty ratio of the drive current by the control device 50.

  The heat sink 243 dissipates heat generated with the light emission of the light source 231. The light emitted from the light source 231 is converted into parallel light by the collimating lens 232. The UV-IR cut filter 233 absorbs and removes ultraviolet light and infrared light from the parallel light that has passed through the collimating lens 232. The polarizer 234 changes the light that has passed through the UV-IR cut filter 233 into unpolarized P-polarized light.

  The light control element 250 attenuates the light that has passed through the polarizer 234 and adjusts the intensity of the light incident on the image display element 240. The light control element 250 includes a shutter with a variable aperture size, a liquid crystal filter with variable transmittance, and a plurality of ND (Neutral Density) filters with different transmittances. The dimming element 250 is connected to the control device 50, and a light reduction amount of light transmitted through the dimming device 250 can be adjusted by a control signal from the control device 50. The light that has passed through the light control element 250 enters the fly-eye lens 235. The fly-eye lens 235 adjusts the brightness of the light transmitted through the light control element 250 uniformly.

  The reflecting mirror 236 changes the optical path of the light transmitted through the fly-eye lens 235 of the illumination unit 230 by 90 degrees. The light reflected by the reflecting mirror 236 is collected by the field lens 237. The light collected by the field lens 237 is irradiated to the image display element 240 via the polarization beam splitter 238 and the phase difference plate 239 that transmit the P-polarized light.

  The image display element 240 includes red, green, and blue color filters for each pixel. The light emitted to the image display element 240 has a color corresponding to each pixel, is modulated by the liquid crystal composition included in the image display element 240, and becomes S-polarized image display light toward the polarization beam splitter 238. Emitted. The emitted S-polarized light is reflected by the polarization beam splitter 238, changes its optical path, passes through the analyzer 241, and then enters the projection lens 242. The image display light transmitted through the projection lens 242 exits the image projection unit 210 and enters the intermediate mirror 350.

  Next, the control device 50 according to the embodiment will be described with reference to FIG. FIG. 3 is a block diagram illustrating a functional configuration of the control device 50. The control device 50 adjusts the brightness of the projected image display light by controlling the light source 231, the image display element 240, and the dimming element 250 in accordance with an input signal for determining the brightness value of the image display light. To do. In the present embodiment, by controlling the light emission intensity of the light source 231 and controlling the dimming amount of the light transmitted through the light control element 250, the range of luminance values of the image display light that can be selected is widened to make it more visible. High-quality image display light is presented.

  The control device 50 includes a reception unit 510, a determination unit 520, an image generation unit 530, and a drive unit 540. The drive unit 540 includes a first drive unit 541, a second drive unit 542, and a third drive unit 543.

  Hereinafter, each block shown in the block diagram of the present specification can be realized in hardware by an element such as a CPU of a computer or a mechanical device, and in software by a computer program or the like. Then, the functional block realized by those cooperation is drawn. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms by a combination of hardware and software.

  The accepting unit 510 accepts input of external information that is an input signal for determining the luminance value of the image display light. The reception unit 510 receives illuminance values detected by the illuminance sensor 60 and vehicle information from the in-vehicle sensor group 800 as external information. Specific examples of the vehicle information from the in-vehicle sensor group 800 include illuminance information from an illuminance sensor provided in the vehicle body, information indicating a lighting state of the headlight, and the like.

  The determination unit 520 determines the luminance value of the image display light based on the external information received by the reception unit 510. The determination unit 520 holds a luminance table in which the luminance value is determined for each of the plurality of luminance steps as a table for determining the luminance value of the image display light, and determines the luminance table based on the illuminance value detected by the illuminance sensor 60. Select one of the luminance steps.

  FIG. 4 is a diagram illustrating an example of a brightness table held by the control device 50. As shown in FIG. 4, in the luminance table according to the present embodiment, 30 luminance values are determined corresponding to each of the luminance steps divided into 30 as the luminance value of the image display light. The smaller the luminance step value, the smaller the luminance value, and the larger the luminance step value, the larger the luminance value.

  When the illuminance value detected by the illuminance sensor 60 is high, the determination unit 520 selects a luminance step having a relatively high luminance value. On the other hand, when the illuminance value detected by the illuminance sensor 60 is low, a luminance step having a relatively low luminance value is selected. Note that the number of luminance steps is merely an example, and a different number of luminance steps may be defined as the luminance table.

  FIG. 5 is a graph showing the relationship between the luminance step and the luminance value defined in the luminance table. In the luminance table according to the present embodiment, the luminance value is determined so that the luminance value of the image display light increases exponentially as the luminance step increases. As a result, it is possible to set a luminance value that matches the visual characteristics of the human eye, and to increase the contrast ratio between the luminance value set the darkest and the luminance value set the brightest. For example, the brightness value set to the darkest corresponding to the brightness step 1 is a brightness value selected at night and in an external environment where there is no street light and the surroundings are surrounded by darkness. On the other hand, the brightness value set most brightly corresponding to the brightness step 30 is a brightness value selected under circumstances where the surroundings are very bright during the day in fine weather.

  After determining the luminance value of the image display light, the determination unit 520 determines the operation of the driving unit 540 so that the luminance value is realized. Specifically, with reference to the luminance table shown in FIG. 4, the current coefficient and duty ratio of the driving current of the light source 231 determined in the luminance table and the light reduction amount of the light control element 250 are determined. The determination unit 520 operates the drive unit 540 so that the light source 231 and the light control element 250 are driven based on the determined control values.

  As shown in FIG. 4, in the luminance table held by the determination unit 520, the current coefficient and duty ratio of the driving current of the light source 231 and the light reduction amount of the dimming element 250 are determined for each luminance step. In the present embodiment, the current coefficient, the duty, in the first range corresponding to the luminance steps 1 to 3, the second range corresponding to the luminance steps 4 to 16, and the third range corresponding to the luminance steps 17 to 30. There is a difference in the way of setting the three parameters of ratio and light reduction. Here, the current coefficient is a coefficient that is multiplied by the value of the rated current of the light source 231 in order to calculate the current value of the drive current. For example, if the rated current is 1 A, the drive current corresponding to a current coefficient of 100% is 1 A.

  In the second range and the third range corresponding to the luminance steps 4 to 30, the current coefficient and the duty ratio are set to be different depending on the magnitude of the luminance value, while the degree of dimming by the dimming element 250 is set. The parameter is set so that a constant light reduction amount (first light reduction amount) is obtained. Specifically, 0% is uniformly set as the first light reduction amount in the second range and the third range. The current coefficient is set to 14% in the second range and set to 100% in the third range. The duty ratio is set to a different value depending on the luminance value. As described above, in the second range and the third range, the luminance value of the image display light is adjusted by controlling the light emission intensity of the light source 231 without changing the light reduction amount of the light control element 250.

  On the other hand, in the first range corresponding to the luminance steps 1 to 3, the current coefficient and the duty ratio are set to constant values, and the parameters are set so that the amount of light reduction varies depending on the luminance value. This is because in the first range where the luminance value is set to be low, the difference in luminance value due to the difference in luminance step is small, so it is difficult to finely adjust the luminance value by changing the drive current of the light source 231. Therefore, in the first range, the light emission intensity of the light source 231 is constant, and the light reduction amount by the light control element 250 is a second light reduction amount larger than the first light reduction amount. Control the value. Specifically, 10%, 15%, and 20% are set as the second light reduction amount according to the magnitude of the luminance value. Thereby, even in the first range where the luminance value is set to be low, the luminance value of the image display light can be finely adjusted to present the image display light with appropriate brightness.

  Here, the threshold value of the luminance value that divides the first range in which the second dimming amount having a different size is set from the second range and the third range in which the first dimming amount that is a constant value is set is: It is determined by the characteristics of the light source 231 and the dynamic range of the required luminance value of the image display light. For example, when the luminance value of the image display light is lowered by reducing the light emission intensity of the light source 231 without using the dimming element 250, the threshold value is small in the current value or the duty ratio of the drive current. Therefore, it can be determined as a luminance value that makes it difficult to obtain a stable emission intensity. In this embodiment, the luminance value of the image display light corresponds to this threshold value when the light source 231 is driven with a current coefficient of 14% and a duty ratio of 5%, and the dimming amount of the light control element 250 is 0%. It should be noted that a value different from the value determined by such a criterion may be adopted as the threshold value of the luminance value that separates the first range and the second range.

  Returning to FIG. 3, the image generation unit 530 generates image information to be displayed as image display light to the user. The image generation unit 530 converts the video acquired from the external device 700 into a format to be output to the third drive unit 543, or generates an OSD (On Screen Display) for displaying the setting screen of the control device 50 to the user. . Here, examples of the video acquired from the external device 700 include a navigation image acquired from a car navigation system, a video acquired from a DVD (Digital Versatile Disc) player, a navigation image acquired from a smartphone, or a video acquired from an in-vehicle camera. It is. Note that the image generation unit 530 may adjust the brightness of the image information to be generated according to the luminance value determined by the determination unit 520.

  The first drive unit 541 outputs a signal for driving the light source 231. The first drive unit 541 generates a drive signal having a pulse waveform for driving the light source 231 based on the current coefficient and the duty ratio of the drive current determined by the determination unit 520 and outputs the drive signal to the light source 231. The light emission intensity of the light source 231 is determined by the waveform of the drive signal output from the first drive unit 541, and light having a higher light emission intensity is output from the light source 231 as the amplitude value or duty ratio of the drive signal increases.

  The second drive unit 542 outputs a signal for driving the light control element 250. The second drive unit 542 drives the light control element 250 so that the light reduction amount of the light transmitted through the light control element 250 becomes the light reduction amount determined by the determination unit 520. For example, when a shutter is used as the light control element 250, the aperture ratio of the shutter is controlled so that the light reduction amount of the light transmitted through the shutter becomes a predetermined value. When a liquid crystal filter is used as the light control element 250, the voltage applied to the liquid crystal layer is controlled. In addition, when the dimming element 250 is configured by a plurality of ND filters, the driving mechanism that determines the position of the ND filter is controlled, and the ND filter located on the optical axis through which the light from the light source 231 passes is switched to control the light reduction amount. To do.

  The third drive unit 543 receives the image information generated by the image generation unit 530 as an input and outputs a signal for driving the image display element 240. The third drive unit 543 drives the image display element 240 so that the image display light modulated by the image display element 240 becomes an image generated by the image generation unit 530.

  The operation of the control device 50 having the above configuration will be described. FIG. 6 is a flowchart showing an operation flow of the control device 50. The control device 50 receives external information for determining the luminance value of the image display light (S12), and determines the luminance value of the image display light according to the received external information (S14). If the determined luminance value is equal to or greater than the predetermined threshold (Y in S16), the light source 231 is driven so as to have a different light emission intensity according to the luminance value (S18), and the constant first that does not depend on the luminance value. The dimming element 250 is driven so as to reduce the amount of light (S20). When the determined luminance value is less than the predetermined threshold value (N in S16), the light source 231 is driven so as to have a constant light emission intensity regardless of the luminance value (S22), and the magnitude is set according to the luminance value. The dimming element 250 is driven so as to have a different second light reduction amount (S22).

  An example of the threshold value in FIG. 6 corresponds to a luminance value between the first range and the second range shown in FIG. Moreover, the case where the determined luminance value is equal to or greater than a predetermined threshold is a case where the luminance value corresponds to the second range or the third range illustrated in FIG. In the range above this threshold, the current coefficient and the duty ratio of the light source 231 are adjusted according to the luminance value, and the amount of light reduction by the dimming element 250 is set to 0 as the first light reduction amount. The state in which the light reduction amount of the light control element 250 is 0 is a state in which the diaphragm is opened when the light control element 250 is a shutter with a variable aperture, and when the light control element 250 is a liquid crystal filter. Is a state in which the transmittance of the liquid crystal filter is maximized. Further, when the light control element 250 is an ND filter, the ND filter is not inserted on the optical path. That is, the second drive unit 542 is operated so that the dimming by the light control element 250 is not performed in a range equal to or greater than the threshold.

  Further, the case where the determined luminance value is less than the predetermined threshold is a case where the luminance value falls within the first range shown in FIG. In a range less than this threshold, the current value of the current for driving the light source 231 and the duty ratio are constant, and the luminance value is controlled by adjusting the amount of light reduced by the light control element 250. Here, the control of the amount of light reduction by the light control element 250 is control in which the amount of the diaphragm is changed when the light control element 250 is a shutter that changes the diaphragm, and the light control element 250 is a liquid crystal filter. The control is to change the transmittance of the liquid crystal filter. When the dimming element 250 is an ND filter, the transmittance is changed by inserting the ND filter on the optical path or by inserting a plurality of ND filters having different transmittances into the optical path. Control. That is, in the range less than the threshold value, the second drive unit 542 is operated so that the dimming by the dimming element 250 is performed.

  With the above configuration, the control device 50 according to the present embodiment can control the luminance value of the image display light by a combination of the light emission intensity of the light source 231 and the light reduction amount of the light control element 250. For this reason, compared with the case where only one of the light source 231 and the light control element 250 is controlled, the range in which the luminance value of the image display light can be changed can be increased. Accordingly, it is possible to present image display light having a high luminance value under a situation where brighter image display light is required, and to present image display light having a low luminance value under a situation where darker image display light is required. . Thereby, even when the external brightness changes greatly, it is possible to appropriately control the luminance value and present image display light with high visibility.

  Further, according to the control device 50 in the present embodiment, when the luminance value of the image display light is less than the predetermined threshold, the degree of dimming by the light control element 250 is increased, and the light source 231 to the image display element. The brightness of the illumination light toward 240 can be further reduced. In the present embodiment, since LCOS which is a reflection type liquid crystal display panel is used as the image display element 240, light from the light source 231 is displayed even when a “black” background where light as image display light is not presented is projected. May be reflected slightly. When the outside is bright, the background light corresponding to “black” is not conspicuous, but when the outside is dark, the background light projected onto the windshield 610 is conspicuous, which may reduce visibility. . In the present embodiment, by using the light control element 250, the light traveling from the light source 231 to the image display element 240 can be made darker, so that reflection of background light can be further reduced. Accordingly, even when the external brightness is very dark, it is possible to appropriately control the luminance value and present image display light with high visibility.

  Further, according to the control device 50 in the present embodiment, when the luminance value of the image display light is less than the predetermined threshold, the dimming element 250 changes the degree of dimming, so that the image display with a low luminance value is performed. The difference in light brightness can be set finely. Under circumstances where the outside is very dark, a subtle difference in luminance values tends to be noticeable as visual characteristics of the human eye. Therefore, by finely controlling the difference in luminance of image display light having a low luminance value, image display light with more appropriate luminance can be presented, and the visibility of the image display light can be enhanced.

  As described above, the present invention has been described with reference to the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and the configurations of the embodiments are appropriately combined or replaced. Those are also included in the present invention.

  In the above-described embodiment, in order to realize a luminance value less than the threshold value, the driving current of the light source 231 is made constant regardless of the luminance value in the first range. In the modification, the parameters of the luminance table may be determined so that the driving current of the light source 231 is changed even in the first range.

  In the above-described embodiment, the range of the luminance value equal to or higher than the threshold value is divided into two ranges of the third range and the second range according to the magnitude of the current coefficient to be set. In a modification, it is good also as setting a parameter in a different aspect about the luminance value more than a threshold value. For example, the current coefficient to be set may be divided into three or more ranges as a range of luminance values that are equal to or greater than the threshold by setting three or more current coefficients. Further, a luminance value equal to or higher than the threshold value may be realized by appropriately combining the current coefficient and the duty ratio.

  In the above-described embodiment, the dimming element 250 includes any one of a shutter having a variable aperture size, a liquid crystal filter having a variable transmittance, and a plurality of ND filter groups having different transmittances. showed that. In a modification, the light from the light source 231 may be dimmed by combining a plurality of these light control elements. By appropriately combining the light control elements, the luminance value less than the threshold value can be controlled more appropriately.

  DESCRIPTION OF SYMBOLS 50 ... Control apparatus, 210 ... Image projection part, 231 ... Light source, 240 ... Image display element, 250 ... Dimming element, 510 ... Reception part, 520 ... Determination part, 530 ... Image generation part, 540 ... Drive part, 541 ... 1st drive part, 542 ... 2nd drive part, 543 ... 3rd drive part.

Claims (5)

A light source;
A reflective image display element that modulates light by reflecting light from the light source and generates image display light including background light corresponding to a black background portion included in an image to be displayed;
A dimming element that is provided between the light source and the image display element and dimmes light from the light source toward the image display element;
A control unit for controlling a luminance value of the image display light;
With
The controller is
A first driving unit that outputs a signal for driving the light source;
A second drive unit that outputs a signal for driving the light control element;
A receiving unit that receives an input signal related to the brightness of an external environment for adjusting the luminance of the image display light;
A determination unit that determines operations of the first drive unit and the second drive unit according to an input signal received by the reception unit;
With
The determination unit
When the luminance value of the image display light is set to a predetermined threshold value or more, the second drive unit is operated so that the degree of dimming by the dimming element becomes the first dimming amount, and the light from the light source Operating the first drive unit so that the light emission intensity corresponds to the luminance value,
When the luminance value of the image display light is less than the predetermined threshold, the first driving unit is operated so that the light emission intensity of the light source is constant, and the degree of dimming by the dimming element is the first level. Operating the second drive unit so that the second light reduction amount is larger than the one light reduction amount ;
When the brightness of the external environment received by the receiving unit is less than a predetermined value, the first driving unit and the second driving unit are set such that the luminance value of the image display light is less than the predetermined threshold value. by operating an image display, comprising the Nikukusu Rukoto noticeable the background light projected. The determination unit
By operating the second drive unit so that dimming by the dimmer element is not performed, the degree of dimming by the dimmer element becomes the first dimming amount,
The degree of dimming by the dimming element is set to the second dimming amount by operating the second drive unit so that dimming by the dimming element is performed. Item 4. The image display device according to Item 1. In the case where the luminance value of the image display light is less than the predetermined threshold value and the luminance value of the image display light is decreased, the determination unit is configured to increase the amount of light reduction by the dimming element. the image display apparatus according to claim 1 or 2, characterized in that for operating said second drive unit to. A first drive unit that outputs a signal for driving the light source;
A second drive unit that outputs a signal for driving a light control element that diminishes light from the light source and directs the light to a reflective image display element;
Input signal relating to the brightness of the external environment for determining the luminance value of the image display light that is modulated by being reflected by the image display element and includes background light corresponding to the black background portion included in the image to be displayed A reception part for receiving,
A determination unit that determines operations of the first drive unit and the second drive unit according to an input signal received by the reception unit;
With
The determination unit
When the luminance value of the image display light is set to a predetermined threshold value or more, the second drive unit is operated so that the degree of dimming by the dimming element becomes the first dimming amount, and the light from the light source Operating the first drive unit so that the light emission intensity corresponds to the luminance value,
When the luminance value of the image display light is less than the predetermined threshold, the first driving unit is operated so that the light emission intensity of the light source is constant, and the degree of dimming by the dimming element is the first level. Operating the second drive unit so that the second light reduction amount is larger than the one light reduction amount ;
When the brightness of the external environment received by the receiving unit is less than a predetermined value, the first driving unit and the second driving unit are set such that the luminance value of the image display light is less than the predetermined threshold value. by operating a control device according to claim Nikukusu Rukoto noticeable the background light projected. A light source;
An image display element that modulates light from the light source and generates image display light including background light corresponding to a black background portion included in an image to be displayed;
A dimming element that is provided between the light source and the image display element and dimmes light from the light source toward the image display element;
A control unit for controlling the luminance value of the image display light,
The controller is
A first driving unit that outputs a signal for driving the light source;
A second drive unit that outputs a signal for driving the light control element;
A reception unit for receiving an input signal related to the brightness of the external environment;
A determination unit that determines operations of the first drive unit and the second drive unit according to an input signal received by the reception unit;
The determining unit operates the first driving unit so that the light emission intensity of the light source is constant when the brightness of the external environment received by the receiving unit is less than a predetermined value, and the dimming element The image display device is characterized in that the second driving unit is operated so that the light is dimmed according to the brightness of the external environment to make the projected background light less noticeable.

Images