JP2012078619A - Transmission display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a double image when an angle of incidence to a narrow band filter is varied when a reflection wave length range in the narrow band filter is narrow.SOLUTION: The occurrence of the double image is prevented even when the reflection range of the narrow band filter is made narrow by varying the wave length of a light source according to the variation in the incidence angle to the narrow band filter.

Description

  The present invention relates to a transmissive display device that displays an image superimposed on an external scene that can be seen from a transmissive display unit, and can visually recognize the image and the external scene together.

  A driver driving a vehicle such as an automobile is required to safely and quickly grasp the situation outside the vehicle, read the information on the display device of the vehicle, and drive the vehicle. It is desirable that the information on the display device of the vehicle can be read within the range necessary for grasping the situation outside the vehicle while driving. Therefore, for example, realization of an image display device that displays characters or images by irradiating light to a part of a transparent plate such as a windshield of a vehicle is expected.

  As such a transmissive display device, a head-up display (hereinafter referred to as “HUD”) that displays driving information on a windshield of an automobile, and a head-mounted display (“Head-Mounted”) that displays information on the lens portion of the glasses. Display (hereinafter referred to as “HMD”). If such a transmission type device is used, the driver can see driving information (for example, a map and a speedometer) at the same time while visually recognizing the outside world, so the driver is expected to be able to drive more safely. Has been.

  Some conventional HUDs project a virtual image onto a windshield. FIG. 1 shows an example of a conventional HUD. In this example, the front glass portion reflects the display light toward the driver, so that the outside world and the display light can be simultaneously viewed.

  In FIG. 1, reference numeral 101 denotes a vehicle body on which a HUD is mounted. Reference numeral 102 denotes a HUD optical unit stored inside the dashboard, and includes a display unit 103 and a deflection unit 104 therein. The display unit 103 includes, for example, a liquid crystal element and a light source, and displays information to be displayed on the driver 107. The display light displayed on the display unit 103 is projected toward the deflecting unit 104. The deflecting unit 104 is configured by a mirror or the like, and deflects the display light from the display unit 103 toward the windshield 106. The display light deflected by the deflecting means 104 passes through the opening 105 of the HUD optical unit 102 and is projected onto the windshield 106. The windshield 106 reflects display light from the HUD optical unit 102 toward the driver 107. The driver 107 can view information related to driving by viewing the display light reflected by the windshield 106. The eye box 108 indicates a range where the image can be seen when the driver 107 moves his head. When the driver 107's eyes are inside the eye box 108, the display light reaches the retina of the driver 107, and the driver 107 visually recognizes the image. can do. Further, the windshield 106 reflects display light from the HUD optical unit 102 and transmits light from the outside (outside) of the windshield. Depending on the performance of the windshield, the driver 107 can view the external scene outside the windshield together with the information displayed by the display means 103. As described above, in the HUD, since the driver 107 can see information from the display means without changing his / her line of sight from the outside, the driver is less required to move his / her line of sight and the safety during driving is improved.

  In the present specification, the rate at which light from the outside of the windshield reaches the interior of the vehicle via the windshield is referred to as the external transmittance. The higher the external transmittance, the clearer the driver 107 can see the scene outside the vehicle.

  However, the conventional HUD that reflects display light by such a windshield has a problem that a double image is generated. This example is shown using FIG. FIG. 2 is a diagram showing a configuration of the windshield 106, and an intermediate film 201 is disposed between two glasses 202 and 203 constituting the windshield. The incident light 204 incident on the windshield is reflected by both the front glass 202 and the rear glass 203 as shown in FIG. 2 to generate display light 205 and reflected light 206. At this time, since the optical path of the display light 205 and the optical path of the reflected light 206 are different depending on the thickness of the glass, when the driver visually recognizes the display light 205 and the reflected light 206 at the same time, the display light 205 looks double. This phenomenon is called a double image. FIG. 3 shows an example of a double image. In FIG. 3, reference numeral 301 denotes an image visually recognized by the driver by the display light 205. Similarly, 302 indicates an image visually recognized by the driver by the reflected light 206. As shown in FIG. 3, since the display positions of the display image 301 and the reflected image 302 are different, the image visually recognized by the driver looks double as shown in FIG. In this specification, the problem that the reflected light from the glass surface and the reflected light from the back surface of the glass are simultaneously recognized by the driver is called a double image problem.

  As a method for this double image problem, there is a method of providing a narrow band filter on the surface of the windshield (for example, Patent Document 1). Here, the narrowband filter refers to a filter that reflects only light in a specific range of wavelengths with high reflectance and transmits light of other wavelengths with high transmittance. FIG. 5 shows an example of the reflection characteristics of the narrow band filter. FIG. 5 shows the reflectance of light of each wavelength when entering the narrowband filter at the designed incident angle θa, and the light of the wavelength included in the reflected wavelength range 501 is reflected by the reflectance R. Light of other wavelengths is transmitted without being reflected. Specifically, a multilayer filter or a rugate filter constituted by laminating a low refractive index material and a high refractive index material can be used as the narrow band filter, and the reflectance R can be obtained by using these filters. Can be increased.

  An example in which such a narrow band filter is used to prevent the generation of a double image is shown in FIG. In FIG. 4, a narrow band filter 401 is installed on the vehicle inner surface of the windshield. At this time, the reflection wavelength region reflected by the narrow band filter 401 is designed to match the wavelength range included in the incident light 204, and the incident light 204 is reflected without passing through the narrow band filter 401. At this time, since the incident light 204 does not reach the back glass 203, reflection at the interface between the back glass 203 and the air does not occur, and the driver sees only the display light 205. In this way, the double image problem can be solved by using the narrow band filter.

JP 58-181004 A

  However, when a narrow band filter is used to deal with the double image problem, there is a problem in dealing with a decrease in external transmittance and a change in eyebox position.

  The narrow band filter also acts on light incident from the outside of the vehicle toward the inside of the vehicle (hereinafter referred to as outside light). For this reason, when the narrow band filter reflects a wide range of wavelengths, the transmittance with respect to external light is lowered. When the narrow band filter has reflection characteristics as shown in FIG. 5, the percentage of the external light transmittance (outside field transmittance) is when the visible light wavelength range is W0 and the narrow band filter reflection wavelength range is W. , The value represented by Equation 1 is obtained. In order to ensure visibility during driving, the higher the external transmittance is, the better. Therefore, it is desirable to set the reflection wavelength range W of the narrow band filter to a small value.

  At this time, if the reflection wavelength range W is made too small in order to increase the external transmittance, a double image may be generated. FIG. 6 shows a diagram when the wavelength range of the light source is larger than the reflection wavelength range of the narrow band filter. As shown in FIG. 6, when the wavelength range of the light source is large and the reflection wavelength range of the narrow band filter is small, light in a wavelength range not included in the reflection wavelength range of the narrow band filter (light in the wavelength range of 602 and 603 in FIG. 6). ) Is transmitted without being reflected by the narrow band filter. Therefore, even if a narrow band filter is provided on the windshield as shown in FIG. 4, a part of the incident light 204 (light in the wavelength range of 602 and 603 in FIG. 6) reaches the back glass. Reflected light that generates a double image is generated. As a method for dealing with this problem, there is a method of using a light source having a narrow wavelength range such as a laser light source as a light source. In general, since the wavelength range of a laser light source is as narrow as several nm, even when the reflection wavelength range of a narrow band filter is small, the light source wavelength range can be contained therein. An example of this is shown in FIG. In this example, since the light source wavelength range 601 is within the reflection wavelength range 501, all the light from the light source is reflected by the narrow band filter and no double image is generated. That is, by using a light source with a narrow wavelength width such as a laser light source, the reflection wavelength range of the narrow band filter can be set small, the external transmittance can be increased, and the occurrence of double images can be suppressed. Become.

  However, when the incident angle of the display light to the narrow band filter is changed in order to change the eye box position, a double image is formed even if a light source having a small wavelength width is used due to the angle dependence of the narrow band filter. It is possible that this will occur

  Here, the angle dependency of the narrow band filter refers to the property that the wavelength of the light reflected by the narrow band filter changes depending on the angle (incident angle) of the light incident on the narrow band filter. In general, a multilayer filter or a rugate filter used as a narrow band filter is configured by laminating a low refractive index material and a high refractive index material. At this time, the larger the incident angle with respect to the narrow band filter, the shorter the wavelength reflected by the narrow band filter. An example of this is shown in FIG. 1201 in FIG. 12 indicates a wavelength range of light reflected by the narrow band filter with respect to light incident at an incident angle θa. Reference numeral 1202 denotes a wavelength range of light reflected by the narrowband filter with respect to light incident at an incident angle θb. At this time, θb is larger than θa. In this specification, the phenomenon that the wavelength reflected by the narrowband filter changes depending on the incident angle of light incident on the filter is referred to as wavelength shift. If the incident angle to the narrow-band filter is changed when changing the eyebox position, this wavelength shift occurs, so that a double image may be generated. Hereinafter, the change of the eyebox position will be described.

  In general, in HUD and HMD, it is necessary to move the position of the eye box 108 according to the height, sitting height, and eye width of the driver. 10 and 11 show examples of eye box position adjustment in the HUD. FIG. 10 shows an example when the eyebox position is high, and FIG. 11 shows an example when the eyebox position is lowered from the state shown in FIG. When the height / sitting height of the driver is high, the eye box position is raised as shown in FIG. 10, and when the height / sitting height of the driver is low, the position of the eye box 108 is lowered as shown in FIG. By matching the position of the eye with the position of the eye box 108, the driver can visually recognize the display image by the HUD. 10 and 11, the position of the eye box 108 is changed by changing the incident angle at which the display light L emitted from the opening portion 105 of the HUD is incident on the windshield 106. In the example of FIG. 10, the display light L is incident on the windshield 106 at a large incident angle 1001, thereby increasing the emission angle of the display light L from the windshield and increasing the position of the eye box 108. . In contrast, in the example of FIG. 11, the display light L is incident on the windshield 106 at an incident angle 1101 smaller than the incident angle 1001 of FIG. 10, thereby reducing the emission angle of the display light L from the windshield. The position of the box 108 is lowered. Thus, by changing the incident angle of the display light with respect to the windshield 106, the position of the eye box 108 can be appropriately changed.

  However, when the incident angle on the windshield 106 is changed to change the position of the eye box 108, the incident angle on the narrow band filter on the windshield also changes. Therefore, the reflection wavelength range of the narrow band filter changes due to the influence of the wavelength shift described above. As a result, when the output wavelength of the light source is out of the reflection wavelength range of the narrow band filter, the light from the light source is not reflected by the narrow band filter, and a double image is generated. An example of this is shown in FIG. Reference numeral 1301 in FIG. 13 denotes a reflection wavelength range of the narrow band filter before the eye box position is moved, and reference numeral 1302 denotes a narrow band filter when the eye box position is increased (when the incident angle to the narrow band filter is increased). The reflection wavelength range is shown. In this example, before moving the eye box position, the wavelength range 601 of the light source is included in the reflection wavelength range 1301 of the narrow band filter, and thus a double image is not generated. However, since the reflection wavelength range 1302 of the narrow band filter after the eye box position is moved does not include the light source wavelength range 601, a double image is generated when the eye box position is increased.

  In order to cope with such a wavelength shift of the narrow band filter by changing the eyebox position, even if the reflection wavelength range of the narrow band filter changes, the light source wavelength range is included in the reflection wavelength range of the narrow band filter. In addition, it is necessary to make the reflection wavelength range sufficiently wide. However, when the reflection wavelength range is large as described above, the external transmittance decreases. That is, there is a trade-off between dealing with the eyebox position change and preventing the decrease in the external transmittance, and it is difficult to achieve both.

  In Patent Document 1, no consideration is given to the relationship between the response to changes in the wavelength range and eye box position of the light source and the external transmittance.

  The present invention solves the above-mentioned conventional problems, and even when the incident angle to the narrow band filter is changed in order to change the eye box position, the reflection of the narrow band filter can be achieved by changing the output wavelength of the light source. An object of the present invention is to provide a transmissive display device capable of preventing the generation of a double image even when the range is narrow.

  In order to solve the above-mentioned problems, a transmissive display device according to the present invention includes a light source that outputs light, display means that receives light emitted from the light source to form an image, and a part of the visible light wavelength range. A narrow band reflecting means for reflecting light in the wavelength range with a high reflectance and transmitting light in other wavelength ranges, and reflecting the light from the display means toward the user; and from the display means Wavelength control means for changing the wavelength output from the light source in response to a change in the incident angle of the light incident on the narrowband reflecting means, and in the wavelength range of light reflected by the narrowband reflecting means A certain reflection wavelength range varies depending on an incident angle of light with respect to the narrow-band reflecting means.

  With this configuration, it is possible to prevent the generation of a double image even when the incident angle to the narrow band filter changes in order to move the eye box position.

  The narrow-band reflecting means of the present invention is a multilayer filter or a rugate filter made of a low refractive index material and a high refractive index material.

  This configuration makes it possible to limit the wavelength reflected by the narrowband filter, increase the transmittance of the narrowband filter, and improve the external visibility of the driver.

  Further, the wavelength control means of the present invention is configured such that, when the incident angle of light incident on the narrowband reflecting means is small, the output wavelength of the light source is included in the reflected wavelength range of the narrowband reflecting means. When the output wavelength of the light source is increased and the incident angle of the light incident on the narrow band reflecting means is large, the output wavelength of the light source is included in the reflected wavelength range of the narrow band reflecting means. The output wavelength is shortened.

  With this configuration, even when the reflection wavelength range of light reflected by the narrow band filter fluctuates due to the influence of the wavelength shift, it is possible to prevent the generation of a double image.

  The light source of the present invention is a laser light source, and the wavelength of the output light becomes longer as the light source temperature is higher.

  By changing the temperature of the light source with this configuration, the wavelength of the display light output from the light source can be changed.

  Further, the wavelength control means of the present invention includes a temperature control means for changing a light source temperature to control an output wavelength of the light source, and a light source output control means for changing a light source output to control a heat generation amount of the light source. It is characterized by having.

  This configuration makes it easy to control the temperature of the light source and control the wavelength of light incident on the narrow band filter.

  Further, the light source of the present invention comprises at least two or more individual light sources that output different wavelengths, and the narrowband reflecting means outputs from the individual light sources for each of the two or more individual light sources. Each individual multilayer film is configured by laminating individual multilayer filters that reflect wavelengths, and the amount of change in reflection wavelength due to the change in the incident angle of the individual multilayer filter is the same for each individual multilayer filter. An average refractive index of the filter is set.

  Even when a plurality of light sources are used according to this configuration, the wavelength shift for each light source can be made the same, so that it is easy to control the wavelengths of the plurality of light sources.

  The transmissive display device of the present invention further includes eye box shape control means for changing the shape of an eye box that allows a user to visually recognize an image, and the eye box shape control means has a light source output of the light source. The eye box shape is changed so that the size of the eye box becomes smaller as the size becomes smaller.

  With this configuration, it is possible to prevent the luminance of the image from decreasing even when the light source output is small.

  The transmissive display device of the present invention further includes a deflecting unit that deflects the display light emitted from the display unit toward the narrow-band reflecting unit, and the deflecting unit directs the incident display light in a specific direction. The deflection means is characterized in that a diffusion angle, which is an angle at which incident display light is diffused, differs for each position on the deflection means.

  With this configuration, the size of the eye box can be changed according to the position where the display light is incident on the deflecting means.

  The eyebox shape control means of the present invention is characterized in that the eyebox shape is changed by changing a position of a projection range in which the display light emitted from the display means is projected on the deflection means. To do.

  With this configuration, even when the light source output is small, the display luminance can be maintained by reducing the size of the eye box.

  The transmission type display device according to the present invention is characterized in that the diffusion angle of the display light incident on the deflection unit is different in the right angle region of the deflection unit and the left region of the deflection unit. To do.

  With this configuration, the eyebox shape can be changed by moving the projection area of the display image on the deflection means to the left and right.

  The eyebox shape control means of the present invention is characterized in that the position of the projection range of the display light on the deflection means is changed by moving the position of the deflection means.

  With this configuration, the shape of the eye box can be changed without changing the position of the virtual image visually recognized by the driver.

  The display means of the present invention has display light deflection means for changing the direction of the emitted display light, and the eyebox shape control means is incident on the deflection means from the display means by the display light deflection means. The position of the projection range of the display image on the deflection unit is changed by changing the incident angle of the display light.

  According to the present invention, it is possible to change the eye box shape without moving the position of the deflecting means.

  Further, the display light deflecting means of the present invention is characterized in that the emission direction of the display light is changed by changing the direction of the display means.

  With this configuration, it is possible to reduce the volume for moving the optical system when changing the eyebox shape.

  Further, the display light deflecting means of the present invention is a dynamic hologram that is installed in an opening portion through which the display means emits display light and can switch the presence or absence of a deflection function by applying a voltage. .

  With this configuration, it is possible to change the projection range of the display image on the deflecting unit without using moving parts.

  Further, the deflecting means of the present invention is a fly eye mirror composed of a minute concave mirror, and the curvature radius of each fly eye mirror varies depending on the position on the deflecting means.

  With this configuration, it becomes possible to change the diffusion angle in accordance with the position on the deflection means.

  In the transmissive display device of the present invention, the diffusion angle, which is the range in which the light diffused at the point on the deflecting means spreads, is reflected when the incident angle to the narrowband reflecting means changes by the value of the diffusion angle. The amount of change in wavelength is smaller than the width of the reflection wavelength range of the narrow-band reflecting means.

  With this configuration, it is possible to prevent the occurrence of double images even when the transmittance of the narrow band filter is high.

  The deflecting means of the present invention is characterized in that the display light incident on the center of the deflecting means has the largest diffusion angle.

  With this configuration, the eye box at the center of the screen can be widened, and the visibility of the driver with respect to the center of the screen can be improved.

  The transmission type display device of the present invention further includes a diffusion sheet that changes a diffusion angle of display light between the deflection unit and the narrowband reflection unit, and the diffusion sheet transmits the sheet depending on a position on the sheet. The eyebox shape control means changes the eyebox shape by changing the position of the diffusion sheet.

  With this configuration, it is not necessary to operate the optical system in the HUD optical unit, and the size of the optical unit can be reduced.

  According to the transmissive display device of the present invention, it is possible to maintain a high external transmittance while preventing the generation of a double image by changing the light source wavelength according to the change in the incident angle to the narrow band filter. become.

Configuration diagram of conventional HUD Diagram showing an example of a conventional double image problem Figure showing an example of how the double image looks The figure which shows the example of the double image measure with the narrow band filter Figure showing an example of the reflection characteristics of a narrowband filter The figure which shows the example of the wavelength range of the narrow band filter and the light source when the double image occurs The figure which shows the example of the wavelength range of a narrow band filter and a light source when a double image does not occur Configuration diagram of HUD in Embodiment 1 of the present invention The figure which shows the spreading | diffusion characteristic of the screen in Embodiment 1 of this invention The figure which shows the example of the eye box position when the incident angle to the narrow band filter is large The figure which shows the example of the eye box position when the incident angle to the narrow band filter is small The figure which shows the example of the change (wavelength shift) of the reflection characteristic of the narrow band filter The figure which shows the example of the wavelength shift when the incident angle to the narrow band filter is enlarged The figure which shows the example of the cross-sectional shape of the screen shape in Embodiment 1 of this invention The figure which shows the example of the front shape and cross-sectional shape of the screen shape in Embodiment 1 of this invention Configuration diagram of display means in Embodiment 1 of the present invention Another block diagram of the display means in Embodiment 1 of this invention The figure which shows the example of the change of the output wavelength of the light source with light source temperature The figure which shows the example when the light source wavelength and the reflection wavelength range of the narrow band filter agree The figure which shows another example in case the light source wavelength and the reflection wavelength range of a narrow-band filter correspond. The figure which shows the operation example of the optical system at the time of changing the eyebox position in this Embodiment 1. Configuration diagram of temperature control means in the first embodiment The figure which shows the functional block of the control means in this Embodiment 1. The figure which shows the functional block of the eyebox position change means in this Embodiment 1. The figure which shows the control flow for the double image prevention of the control means in this Embodiment 1. The figure which shows the table | surface of the influence of the wavelength shift of the narrow-band filter in this Embodiment 1. The figure which shows the detailed flow of the light source output control in this Embodiment 1. The figure which shows the detailed flow of the eyebox shape control in this Embodiment 1. Diagram showing an example of the relationship between the diffusion angle of display light from the screen and the eyebox size The figure which shows the example of the spreading | diffusion performance of the screen in this Embodiment 1, and the position of the projection area | region of the display light on a screen The figure which shows another example of the spreading | diffusion performance of the screen in this Embodiment 1, and the position of the projection area | region of the display light on a screen The figure which shows the example of the eyebox shape at the time of using the screen in this Embodiment 1. The figure which shows the example of the eyebox shape at the time of using the screen in this Embodiment 1. The figure which shows another example of the spreading | diffusion performance of the screen in this Embodiment 1, and the position of the projection area | region of the display light on a screen The figure which shows the example of the eyebox shape at the time of using the screen in this Embodiment 1. The figure which shows the relationship between the horizontal position of the screen in this Embodiment 1, and the vertical direction size of an eyebox. Another view showing the relationship between the horizontal position of the screen and the vertical size of the eyebox in the first embodiment The figure which shows the structural example of the screen in case the spreading | diffusion performance of the screen in this Embodiment 1 differs in a perpendicular direction. HUD configuration diagram in the case where a diffusion sheet for changing the diffusion angle of display light is provided in the opening portion in the first embodiment The figure which shows the example of the diffusion characteristic of the screen for reducing eye box size The figure which shows another example of the diffusion characteristic of the screen for reducing eyebox size The figure which shows the example of an optical system change in the case of changing the eyebox position by moving a HUD optical unit in parallel in this Embodiment 1. FIG. Configuration diagram of HMD in the second embodiment

Calculation formula showing external transmittance

Calculation formula showing wavelength change due to light source temperature

Calculation formula showing wavelength shift of narrowband filter

Relational expression showing endothermic amount of Peltier element

Relational expression between light source output and display performance (luminance, display image size, eyebox size)

Calculation formula for obtaining display luminance in the first embodiment

Formula for calculating the screen diffusion angle

Formula for obtaining the eyebox size in the first embodiment

Formula for obtaining the eyebox size in the first embodiment

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
In this embodiment, even when the incident angle of the display light to the narrow band filter is changed in order to change the eye box position, the output wavelength of the light source is changed by utilizing the temperature dependence of the light source wavelength. A HUD capable of preventing the occurrence of a double image will be described.

  In general, the output wavelength of a laser light source varies with temperature. FIG. 18 shows the change in laser output wavelength with temperature. The laser light source shown in FIG. 18 indicates that the output wavelength increases as the temperature increases. When the temperature is T and the coefficient is C, the output wavelength of the light source at the temperature T is expressed as in Equation 2. For this reason, even if the wavelength range of the laser light source at a certain temperature is narrow, the wavelength range output by the laser light source changes in the range from λmin to λmax (temperature change range Wt in FIG. 18) as the ambient temperature changes. .

  In the present invention, the temperature dependence of the light source wavelength is used, and when the reflected wavelength range of the narrow band filter fluctuates due to the wavelength shift, the light source temperature is adjusted so that the output wavelength of the light source falls within the reflected wavelength range of the narrow band filter. Change. Thus, even if the incident angle of the display light to the narrow band filter is changed in order to change the eye box position, it is possible to prevent the generation of a double image.

  Hereinafter, a countermeasure method for the double image problem using the temperature dependence of the light source wavelength will be described in detail.

  FIG. 8 shows a configuration diagram of a HUD (head-up display) in the first embodiment of the present invention. In FIG. 8, reference numeral 101 denotes a vehicle body on which a HUD is mounted, and includes a HUD optical unit 102 inside the dashboard. The HUD optical unit 102 includes a display unit 103, a screen 801, a control unit 802, an opening 105, and an eye box position deflection unit 803. The display means 103 displays driving information (speedometer and map information) and the like for the driver 107.

  The display means 103 in this embodiment includes a liquid crystal element and a backlight light source. FIG. 16 shows a configuration example of the display unit 103.

  In this embodiment mode, the light source of the display means is a laser light source, and output laser light from the red laser light source 1601, blue laser light source 1602, and green laser light source 1603 is passed through a collimator 1604 and combined by a dichroic mirror 1605. Yes. By appropriately modulating the output from each color laser light source, laser light of any color can be output. In FIG. 16, 1601 is a red (R) semiconductor laser light source, 1602 is a blue (B) semiconductor laser light source, and 1603 is a green (G) semiconductor laser light source, but 1603 is an infrared semiconductor laser light source, A combination of SHG (Second Harmonic Generation) elements that convert infrared rays into green may be used, and each light source may be a solid laser, a liquid laser, a gas laser, or a light emitting diode.

  In FIG. 16, the laser light is modulated by each laser light source. However, the laser light may be modulated by using means for modulating light output from the laser light source in combination with the laser light source.

  After the light from the laser light sources 1601 to 1603 is diffused by the illumination optical element 1606, the liquid crystal element 1607 is irradiated to form display light L. The display light L from the liquid crystal is further emitted from the display unit 103 by passing through the projection lens 1608.

  The display unit 103 includes a temperature detection unit 1609 that detects the temperatures of the laser light sources 1601 to 1603. By detecting the temperature of the light source, it is possible to estimate the output wavelength of the light source according to the temperature. The temperature detection unit 1609 may detect the temperatures of all the light sources, or different temperature detection units may be provided for each of the RGB light sources. In the latter case, the temperature of each light source can be detected more accurately.

  The display unit 103 includes a temperature control unit 1610 that controls the temperatures of the laser light sources 1601 to 1603. By controlling the temperature of the light source, the output wavelength of each light source can be controlled. FIG. 22 shows a configuration example of the temperature control means 1610. In the present embodiment, the temperature control means 1610 includes a Peltier element 2201 and a heat dissipation means 2202. The Peltier element 2201 is an element for moving the heat from one side of the element to the opposite side, and can control the amount of heat to be moved by passing an electric current. In this embodiment mode, the Peltier element 2201 provided in the display unit 103 has a function of moving heat generated by the light source with respect to the heat dissipation unit 2202. The heat radiating means 2201 has a function of radiating received heat. In this embodiment, the Peltier element 2201 moves the heat generated from the laser light sources 1601 to 1603 to the heat radiating means 2202, and the heat radiating means 2202 transfers the heat from the Peltier element 2201 to the outside of the display means 103 or the HUD optical unit 102. By dissipating, the display means 103 or the laser light sources 1601 to 1603 can be cooled. The Peltier element 2201 does not receive heat from the laser light sources 1601 to 1603, but can also move heat from the outside to the laser light sources 1601 to 1603, so that the temperature of the laser light sources 1601 to 1603 is increased. Can be made. By using such temperature control means 1610, the temperature of the laser light sources 1601 to 1603 can be controlled.

  In the present embodiment, the temperature control unit 1610 controls the temperature of the laser light sources 1601 to 1603 by controlling the temperature of the entire display unit 103. However, the temperature control unit 1610 includes a temperature control unit 1610 for each light source. May be used. In this case, the temperature can be controlled for each light source, and the output wavelength of the light source can be more accurately controlled when a plurality of light sources having different temperature characteristics are used.

  As the heat radiation means 2201, a heat radiation fan or the like may be used instead of the heat radiation fin. In this case, the temperature of the light source can be cooled even when the ambient temperature is high.

  In this embodiment mode, the transmissive liquid crystal element 1607 that irradiates the light source from the back surface is used. However, a reflective liquid crystal element may be used. In this case, the light use efficiency of the light source can be improved, and the display light from the display means 103 can be made brighter.

  As a method of realizing the display unit 103, a method of forming a display image by two-dimensionally scanning output light from a laser light source by a scanning unit instead of a liquid crystal element may be used. In this case, there is an effect that the display unit 103 can be further downsized. FIG. 17 shows a configuration example of the display unit 103 when the scanning unit is used.

  The scanning unit 1701 scans the beams from the laser light sources 1601 to 1603 two-dimensionally toward the opening 1702. The scanning unit 1701 is a single-plate small mirror that can deflect the angle two-dimensionally, and is a MEMS (Micro-Electro-Mechanical-System) micromirror. The mirror is obtained by vibrating the single-plate small mirror in two orthogonal directions. Is scanned in a two-dimensional direction.

  The scanning unit 1701 is not only a method of vibrating one mirror in a two-dimensional direction, but also a method of scanning a laser beam L in a two-dimensional direction by combining two mirrors that vibrate in different one-dimensional directions. Very good. In this case, since each mirror vibrates only in a one-dimensional direction, there is an effect that the control of the angle of each mirror is simplified. Light from the scanning unit 1701 passes through the opening 1702 and is output from the display unit 103.

  The screen 801 receives display light from the display unit 103 and diffuses toward the windshield 106. In the HUD in the present embodiment, the driver 107 visually recognizes an image formed on the screen 801 through the windshield 106. Note that the screen 801 is designed to have different diffusion characteristics depending on the location of the screen in order to control the angle of incidence on the windshield 106. FIG. 9 shows an example of the diffusion performance of the screen 801. As shown in FIG. 9, the display light projected from the screen 801 forms an image on the screen 801, and the light diffuses toward the windshield 106 at a certain diffusion angle, and diffused light (901 in FIG. 9). ˜903) to enter the narrow band filter 401. At this time, the screen 801 is designed so that the diffusion direction of the display light varies depending on the projection position on the screen. Note that solid line arrows in 901 to 903 indicate the light toward the center of the eye box 108 among the diffused light diffused from each point on the screen. In the present embodiment, the direction of this light is the point on the screen. Treated as the diffusion direction from

  In this example, the light incident on the center point of the screen 801 is diffused around the same direction as the normal line 904 of the screen as indicated by 901 in FIG. However, the light incident on the screen edge is diffused with an inclination with respect to the normal 904. For this reason, the incident angle to the narrow band filter differs between the light incident on the center of the screen and the light incident on the screen edge. By using such a screen 801, light from the screen can be efficiently collected in the eye box 108.

  14 and 15 show the shape of the screen 801 in the present embodiment. FIG. 14 is a vertical sectional view of the screen 801, 1501 in FIG. 15 is a horizontal sectional view of the screen 801, and 1502 is a front view of the screen 801. As shown in FIGS. 14 and 15, in the present embodiment, the screen 801 is configured as a fly-eye mirror composed of a minute concave mirror. By using a fly-eye mirror for the screen 801, the diffusion angle of light diffusing from the screen 801 can be controlled by the curvature of the minute concave mirror. Further, as shown in FIG. 14, by changing the inclination of the minute concave mirror according to the position on the screen, it becomes possible to change the diffusion direction of the light diffused at each point on the screen.

  The screen 801 may be a reflection hologram mirror having similar optical characteristics instead of a fly-eye mirror. In this case, there is no need to perform microfabrication for forming the minute concave mirror, and thus there is an effect that the manufacture becomes easy.

  The screen 801 may be a diffuser plate having a concave shape instead of a fly-eye mirror. By making the diffuser plate concave, the diffusion direction of diffused light can be changed according to the position of the diffuser plate. In this case, since it is not necessary to shape the minute concave mirror, there is an effect that the manufacture becomes easy.

  Note that a method of realizing the diffusion characteristics of the screen 801 by combining a microlens array and a mirror instead of the fly-eye mirror may be used as the screen 801.

  The windshield 106 reflects the light from the screen 801 toward the driver 107. Further, in order to solve the above-described double image problem, the narrow band filter 401 is provided on the surface of the windshield inside the vehicle as shown in FIG. As shown in FIG. 7, the narrow-band filter reflects light included in a specific wavelength range (reflection wavelength range 501) within a visible wavelength range with a high reflectance with respect to light incident at a designed incident angle θa. Designed to be. Further, the reflection wavelength range 501 is designed to include the line width (wavelength width at the specific temperature Ta) of the laser light sources 1601 to 1603. For example, when the line width of the light source wavelength is 2 nm, the reflection range has a width of 2 nm or more, and includes the output wavelength range 601 of the light source at the temperature Ta. In the present embodiment, the narrow band filter is formed of a multilayer filter (Lugate filter) to increase only the reflectance in the reflection wavelength range.

  In the present embodiment, the specific temperature Ta is an average value of the minimum light source operation temperature Tmin and the maximum light source operation temperature Tmax shown in FIG. 18, and the design incident angle θa is θf that is an angle between the windshield 106 and the horizontal line. Sometimes, it is treated as a value obtained by subtracting θf from 90 degrees, but different values may be set for each. For example, Ta may be the light source operating average temperature. In this case, the frequency of changing the incident angle with respect to the narrow band filter can be reduced.

  For the sake of simplicity in the present embodiment, the narrow band filter is exemplified only for the reflection characteristics relating to the monochromatic wavelength range (for example, R light source) of the RGB light sources (1601 to 1603). The light source has reflection characteristics and angle dependency.

  Note that the narrowband filter 401 may be realized by stacking three narrowband filters that reflect only the wavelengths of the RGB light sources, or a filter that simultaneously corresponds to the RGB wavelengths. In the former case, there is an effect that it becomes easy to design a narrow band filter according to the temperature characteristics of each light source.

  In the present embodiment, the narrow band filter is realized by a multilayer filter, but a hologram having angle dependency may be used. In this case, the emission angle from the filter can be set to a value different from the incident angle, and the degree of freedom in the optical layout of the HUD can be improved.

  The control unit 802 has a function of controlling the wavelength of the display light emitted from the display unit 103 according to the incident angle of the display light with respect to the narrow band filter 401. FIG. 23 shows a control block of the control means 802 in this embodiment. The control unit 802 includes a wavelength estimation unit 2301, an incident angle estimation unit 2302, a wavelength control unit 2303, a light source output control unit 2304, and an eye box shape control unit 2305, and performs processing for dealing with the double image problem. Details of the functional blocks 2301 to 2305 will be described later.

  The eye box position changing unit 803 has a function of accepting an operation from the driver 107 and changing the position of the eye box 108. FIG. 24 shows a functional block diagram of the eyebox position changing means 803 in the present embodiment. As shown in FIG. 24, the eye box position changing means 803 changes the incident angle at which the display light from the operating means 2401 and the HUD optical unit 102 for the driver 107 to input a desired eye box position enters the windshield 106. The incident angle changing means 2402 is used for this purpose.

  The operation means 2401 is a means for the driver 107 to adjust the position of the eye box 108. In this embodiment, the operation means 2401 is provided as an operation button on the dashboard of the vehicle body 101 on which the HUD is mounted. Has four corresponding buttons. The driver 107 can input an instruction to change the position of the eye box 108 and an instruction to the eye box position changing unit 803 by pressing an operation button corresponding to the direction in which the eye box 108 is to be moved. .

  The position of the operation button may be provided on the handle instead of the dashboard. In this case, the driver 107 can adjust the eye box 108 without releasing his / her hand from the handle during driving. Further, the operation means 2401 may be realized by a touch panel or the like instead of the operation buttons. In this case, the design of the vehicle can be improved. Further, a method of accepting an operation instruction by a driver's voice instead of the operation button may be used. In this case, the driver can change the eyebox position without releasing the hand from the handle.

  The incident angle changing unit 2402 moves the position of the eye box 108 based on the eye box position changing instruction from the driver 107 input to the operation unit 2401. In this embodiment, the HUD optical unit 102 has a rotation function for rotating its own direction, and the incident angle changing unit 2402 uses the rotation function of the HUD optical unit 102 to change the incident angle of the display light with respect to the windshield 106. change. An example of this is shown in FIG. 21 indicates a state of the HUD optical unit 102 when the position of the eye box 108 is high. At this time, the HUD optical unit 102 is horizontal with respect to the horizontal line, and is installed so that the incident angle of the display light with respect to the windshield 106 becomes large. In order to move the position of the eye box 108 downward from this state, the incident angle changing means 2402 uses the rotation mechanism of the HUD optical unit 102 as shown by 2102 in FIG. Rotate forward. At this time, since the incident angle of the display light with respect to the windshield 106 becomes small, the position of the eye box 108 can be moved downward as indicated by 2102. The incident angle changing unit 2402 controls the rotation direction and the rotation amount of the HUD optical unit 102 in accordance with an instruction from the operation unit 2401.

  In the present embodiment, the incident angle to the windshield 106 is changed by rotating the entire HUD optical unit 102. However, the incident angle to the windshield 106 is changed by changing the orientation of the screen 801. Means may be used. Further, the incident angle of the display light to the windshield 106 may be changed by installing a folding mirror in the optical path from the screen 801 to the opening 105 and changing the direction of the folding mirror. In this case, since it is not necessary to move the entire HUD optical unit 102, it is not necessary to provide an extra space for rotating the HUD optical unit 102.

  In order to change the incident angle of the display light to the windshield 106, a deflection element is provided between the opening 105 and the screen 801, and the incident angle with respect to the windshield 106 is changed by changing the direction of the display light by the deflection element. You may use the method of changing. As the deflection element, an electro-optic element, an acousto-optic element, or a variable hologram element (an element capable of recording a diffraction grating on a liquid crystal element and controlling a diffraction function by voltage) can be used. In this case, the display position of the image on the screen 801 can be changed without using moving parts.

  In the present embodiment, the position of the eye box 108 is adjusted by the driver 107 directly operating the operating means 2401, but the position of the eye box 108 may be determined by other methods. A method may be used in which the eyeball position of the driver is detected by an eye camera, and the position of the eyebox 108 is adjusted so that the eyeball position of the driver is included in the eyebox 108. In this case, even when the position of the driver's eyes frequently fluctuates due to vehicle vibration or the like, the driver can visually recognize the HUD display.

  When changing the position of the eye box 108, a method of moving the HUD optical unit 102 in parallel may be used instead of changing the incident angle of the display light on the windshield. An example of this is shown in FIG. 42, 4201 shows a HUD configuration diagram when the position of the eye box 108 is high, and 4202 shows a HUD configuration diagram when the position of the eye box 108 is low. As shown in FIG. 42, the position of the eye box 108 can be lowered by moving the entire HUD optical unit 102 forward and lowering the position where the display light is incident on the windshield 106. In this case, since the incident angle of the display light with respect to the narrow band filter 401 does not change, it becomes possible to prevent the wavelength shift of the narrow band filter. Further, a method of changing the position of the eye box 108 by combining a method of changing the incident angle to the windshield and a method of moving the HUD optical unit in parallel may be used. In this case, a space for moving the HUD optical unit 102 can be reduced.

  A specific procedure when the control unit 802 prevents the occurrence of a double image when the eye box position is changed by the eye box position changing unit 803 will be described below. The transmissive display device in this embodiment prevents the generation of double images by performing the processing of steps 2501 to 2507 shown in FIG. For simplicity, an example of wavelength control of the light source for dealing with a change in incident angle control to the narrow band filter for one color (R wavelength) of RGB wavelengths will be described below.

[Step 2501] (Estimation of light source wavelength)
In this step, the wavelength estimation unit 2301 estimates the output wavelength of the light source included in the display unit 103. The wavelength estimation unit 2301 holds data indicating the relationship between the temperature of the light source and the wavelength as shown in FIG. 18, and obtains the current light source temperature from the temperature detection unit 1609 so that the current output wavelength of the light source is obtained. Is estimated.

  In this embodiment, the method of estimating the output wavelength of the light source from the light source temperature is used. However, a method of providing a spectrum analyzer in the display means 103 and directly measuring the output wavelength of the light source may be used. In this case, the output wavelength of the light source can be measured more accurately.

  The wavelength estimation unit 2301 notifies the wavelength control unit 2303 of information on the estimated output wavelength of the light source.

[Step 2502] (incident angle determination)
In this step, the incident angle estimating unit 2302 determines the incident angle of the display light incident on the narrowband filter 401 from the screen 801 using the information from the incident angle changing unit 2402.

  In the present embodiment, the incident angle changing unit 2402 changes the incident angle of the display light on the windshield 106 in order to move the position of the eye box 108. At that time, the incident angle changing unit 2402 holds the initial incident angle value set in advance and the angle value obtained by rotating the HUD optical unit for changing the eyebox position, and calculates the current incident angle value. . In response to an inquiry from the incident angle estimating unit 2302, the incident angle changing unit 2402 notifies the incident angle estimating unit 2302 of the stored incident angle value.

  As shown in FIG. 9, when the diffusion angle of the light diffused from the screen 801 is large (when the angle formed by the dotted arrows 901 to 903 shown in FIG. 9 is large), the eye box 108 starts from a point on the screen 801. Is used as the incident angle of light incident on the narrowband filter 401 from the screen 801.

  As the incident angle, an angle at which light other than the light traveling toward the center of the eye box is incident on the windshield may be used as the incident angle. For example, an eye camera that captures the position of the driver's eyeball may be installed in the vehicle, and light directed to a position on the eyebox where the driver's eyeball is positioned may be used to determine the incident angle. In this case, it is possible to more accurately determine the incident angle of the display light that is actually visually recognized by the driver. In addition, the incident angle of the central light among the light diffused from each point on the screen with respect to the windshield may be determined as the incident angle of the display light.

  Further, when the incident angle to the windshield is different in the area where the image is displayed (for example, when the image is displayed in the entire area A in FIG. 9, the diffusion direction 902 at the upper part of the image and the diffusion direction 901 at the lower part of the image In such a case, the incident angle at which the display light of the screen portion on which the center pixel of the display image is displayed enters the windshield is used. In this case, it is possible to more accurately prevent the occurrence of double images at the center of the screen where important information is easily displayed.

  When the incident angle to the windshield is different in the area where the image is displayed, the incident angle may be determined based on an area other than the area where the screen center pixel is displayed. For example, the average value of the incident angles of the entire area where the image is displayed may be used, or the gaze point of the driver is measured by an eye camera, and the incident angle is calculated from the screen position corresponding to the pixel the driver is viewing. A determination may be made.

  The incident angle estimation unit 2302 notifies the wavelength control unit 2303 of information related to the estimated incident angle of the display light to the narrow band filter.

[Step 2503] (Reflected wavelength range determination)
In this step, the wavelength control unit 2303 calculates the influence of the wavelength shift from the value of the incident angle with respect to the narrowband filter 401 acquired in the previous step 2502, and the wavelength range of light reflected by the narrowband filter 401 (reflection wavelength range). Calculate

  The wavelength control unit 2303 has information on the reflection wavelength range of the narrow band filter (the reflection wavelength range and the reflectance shown in FIG. 5) with respect to the design incident angle θa and information on the wavelength shift of the narrow band filter. Based on the incident angle acquired from the incident angle estimating means 2302, the current reflection wavelength range of the narrowband filter is determined.

  In the present embodiment, the wavelength control unit 2303 has a relationship table between the difference between the incident angle and the designed incident angle and the amount of wavelength shift shown in FIG. When the current incident angle is 5 degrees larger than the designed incident angle, the reflection wavelength range of the narrow-band filter is shifted from the reflection wavelength range shown in FIG. It is determined that the object is in the position.

  In calculating the wavelength shift amount, a formula for calculating the wavelength shift with respect to the multilayer filter may be used instead of using the relational table as shown in FIG. Formula 3 shows an example of a calculation formula for wavelength shift in the multilayer filter. The amount of wavelength shift can be determined by calculating the difference between the reflected wavelength at the designed incident angle and the reflected wavelength at the current incident angle using this mathematical formula. By using this method, it becomes possible to calculate the amount of wavelength shift in more detail.

  The wavelength control unit 2303 determines whether or not a double image is generated, using the calculated current reflection wavelength range.

[Step 2504] (Dual image determination)
In this step, the wavelength control unit 2303 compares the output wavelength of the light source determined in the previous step 2501 with the reflection wavelength range of the narrow band filter determined in the previous step 2503 to determine whether or not a double image is generated.

  When the output wavelength of the light source is within the current reflection wavelength range of the narrow band filter (when in the state of FIG. 7), all the light from the light source is reflected by the narrow band filter and no double image is generated. Therefore, the wavelength control unit 2303 ends the process.

  When the output wavelength of the light source is not within the current reflection wavelength range of the narrow band filter, a part or all of the wavelength range of the display light from the light source is not reflected by the narrow band filter, and a double image is generated. In this case, the wavelength control unit 2303 performs the process of step 2505 in order to change the light source wavelength.

[Step 2505] (Change of light source wavelength)
In this step, the output wavelength of the light source is changed so that the output wavelength of the light source falls within the reflection range of the narrow band filter.

  The wavelength control unit 2303 calculates the difference between the maximum value of the output wavelength of the light source and the maximum value of the reflection wavelength range of the narrow band filter, and calculates the amount of wavelength error. If the output wavelength of the light source is larger than the reflection wavelength range of the narrow band filter, the temperature of the light source is lowered to decrease the light source output wavelength, and the output wavelength of the light source is smaller than the reflection wavelength range of the narrow band filter In this process, the temperature of the light source is raised to increase the output wavelength of the light source.

  The wavelength control unit 2303 uses the table shown in FIG. 18 to determine the target temperature Tb for changing the output wavelength of the light source by the amount of wavelength error. When the value of the wavelength error is 8 nm (when the maximum value of the output wavelength of the light source is 8 nm larger than the reflection wavelength of the narrow band filter), the target light source temperature Tb for reducing the output wavelength of the light source by 8 nm from the present is set. decide. At this time, the target temperature Tb is set to a value smaller than the current light source temperature.

  The wavelength control unit 2303 controls the temperature of the light source by notifying the temperature control unit 1610 of the determined value of the target temperature Tb. An example in which double images are prevented by controlling the light source temperature is shown in FIGS. The example of FIG. 19 is an example when the light source wavelength becomes larger than the reflection wavelength range of the narrow band filter as a result of the increase in the incident angle to the narrow band filter. At this time, generation of a double image can be prevented by lowering the light source temperature to move the light source wavelength to the position 1901. The example of FIG. 20 is an example in the case where the light source wavelength becomes smaller than the reflection wavelength range of the narrow band filter as a result of the small incident angle to the narrow band filter. At this time, it is possible to prevent the generation of a double image by increasing the light source temperature to move the light source wavelength to the position of 2001.

  In calculating the wavelength error, the difference between the minimum value of the output wavelength of the light source and the minimum value of the reflection wavelength range of the narrow band filter may be calculated. When the output wavelength of the light source is shifted to the short wavelength side with respect to the reflection wavelength range, the difference between the minimum value of the output wavelength of the light source and the minimum value of the reflection wavelength range of the narrow band filter is regarded as a wavelength error, and When the output wavelength is shifted to the long wavelength side with respect to the reflection wavelength range, a method in which the difference between the maximum value of the output wavelength of the light source and the maximum value of the reflection wavelength range of the narrowband filter is used as a wavelength error may be used. good. In this case, the value of the wavelength error can be kept small, and a necessary change in the incident angle can be reduced.

  The wavelength control unit 2303 further notifies the light source output control unit 2304 of the target temperature Tb, and ends the processing of this step 2505.

[Step 2506] (Control of light source output)
In this step, the light source output control unit 2304 controls the light source output so that the light source temperature becomes the target temperature set by the wavelength control unit 2303 in the previous step 2505.

  The light source output control means 2304 performs a process for controlling the light source output after a predetermined time Tc has elapsed. FIG. 27 shows a detailed flow of processing performed by the light source output control means 2304 in the present embodiment. By performing the processing of steps 2701 to 2707 shown in FIG. 27, it becomes possible to perform light source output control for setting the light source temperature to the target temperature Tb. In the present embodiment, the fixed time Tc is a numerical value held by the light source output control means 2304, and a time required for the temperature control means 1610 to change the light source temperature is set. The numerical value of Tc may be a fixed numerical value, or may be a numerical value that the light source output control means 2304 varies as necessary. In the latter case, when the ambient temperature is high and it takes time to cool the light source, control according to the surrounding environment is possible, for example, by increasing the value of Tc.

  Details of the light source output control in this step will be described below based on processing flows 2701 to 2707 shown in FIG.

(Step 2701)
In this step, the light source output control unit 2304 acquires the current temperature Tp of the light source from the temperature detection unit 1609.

(Step 2702)
In this step, the light source output control means 2304 compares the current temperature Tp of the light source with the target temperature Tb. If the current temperature Tp of the light source is higher than the target temperature Tb, the process of step 2703 is performed to output the light source. Reduce. In other cases, the process of step 2704 is performed.

(Step 2703)
In this step, when the light source temperature does not fall below the target temperature Tb, the light source output control means 2304 determines that there is a situation in which the temperature control means 1610 cannot cool the light source temperature.

  In this embodiment, when the light source is cooled to the target temperature, the Peltier element 2201 constituting the temperature control means 1610 absorbs the heat from the light source and moves it to the heat dissipation means 2202. At this time, the heat amount (heat absorption amount) that the Peltier element 2201 should absorb is expressed by the relational expression shown in Equation 4. Here, the ambient heat amount is the amount of heat flowing into the light source from the outside of the light source, and the value increases as the temperature outside the light source (such as the internal temperature of the HUD optical unit 102) increases. The light source heat generation amount is the amount of heat generated by the light source itself, and the light source heat generation amount increases as the light source output increases (when the display light is bright). Other parts correspond to components included in the display unit 103 (such as the display element 1607) and heat generated by a control circuit that implements the control unit 802. In general, the cooling efficiency of the Peltier element 2201 decreases when the heat absorption amount is large. In such a case, since the Peltier element 2201 cannot sufficiently cool the light source, a situation in which the light source cannot be cooled to the target temperature Tb occurs.

  In order to deal with this problem, in the present embodiment, the light source output control means 2304 uses a method of reducing the light source output when the light source temperature does not decrease even after a certain time has elapsed. Generally, since the light source heat generation amount is proportional to the light source output, it is possible to reduce the light source heat generation amount by reducing the light source output, and to reduce the heat absorption amount of the Peltier element 2201.

  In this step 2703, the light source output control means 2304 reduces the light source heat generation amount by reducing the light source output by 10%, and returns to the processing in step 2701 after elapse of a certain time Td. By repeating the processes in steps 2701 to 2703, it becomes possible to bring the current temperature Tp of the light source closer to the target temperature Tb while gradually reducing the light source output.

  In the present embodiment, the fixed time Td is a numerical value held by the light source output control means 2304, but may be a fixed numerical value or a numerical value that the light source output control means 2304 fluctuates as necessary. There may be. In the latter case, when the ambient temperature is high and it takes time to cool the light source, control according to the surrounding environment, such as increasing the value of Td, becomes possible.

  In this embodiment, the light source output control unit 2304 uses a method of reducing the light source output by 10%, but the degree of change in the light source output may not be 10%. For example, a method of decreasing the output by a certain value (for example, 10 mW) may be used, and the degree of change may be controlled according to the ambient temperature (for example, 10 mW when the ambient temperature is low, and 20 mW when the ambient temperature is high). Lower). In this case, it is possible to adjust the degree of temperature change of the light source according to the usage environment of the HUD.

(Step 2704)
In this step, the light source output control means 2304 compares the current temperature Tp of the light source with the target temperature Tb. If the current temperature Tp of the light source is lower than the target temperature Tb, the process of step 2705 is performed to output the light source. To increase. In other cases, the process of step 2706 is performed.

  When the light source temperature does not exceed the target temperature Tb, the light source output control unit 2304 determines that there is a situation in which the temperature control unit 1610 cannot heat the light source temperature. In this case, the light source output control unit 2304 executes the process of step 2705 in order to increase the light source output, thereby increasing the light source heat generation amount and increasing the light source temperature.

(Step 2705)
In this step 2705, the light source output control means 2304 increases the light source heat generation amount by increasing the light source output by 10%, and returns to the processing in step 2701 after elapse of every predetermined time Td. By repeating the processing of steps 2701, 2702, 2704, and 2705, it becomes possible to bring the current temperature Tp of the light source closer to the target temperature Tb while gradually reducing the light source output.

  Alternatively, by repeating the processes 2701, 2702, 2704, 2706 (described later) and 2707 (described later), it becomes possible to increase the light source output while keeping the light source temperature constant.

  In the present embodiment, the fixed time Td is a numerical value held by the light source output control means 2304, but may be a fixed numerical value or a numerical value that the light source output control means 2304 fluctuates as necessary. There may be. In the latter case, when the ambient temperature is low and it takes time to heat the light source, control according to the surrounding environment, such as increasing the value of Td, becomes possible.

  In this embodiment, the light source output control unit 2304 uses a method of increasing the light source output by 10%, but the degree of change in the light source output may not be 10%. For example, a method of increasing the output by a certain value (for example, 10 mW) may be used, and the degree of change may be controlled according to the ambient temperature (for example, 20 mW at the ambient low temperature, and 10 mW at the ambient high temperature). Increase). In this case, it is possible to adjust the degree of temperature change of the light source according to the usage environment of the HUD.

(Step 2706)
In this step, the light source output control means 2304 acquires from the light source temperature control means 1610 the power P used by the current light source temperature control means 1610 and the maximum power Pmax that can be used by the light source temperature control means 1610. .

  In the present embodiment, the value of the maximum power Pmax is acquired from the light source temperature control unit 1610, but the light source output control unit 2304 may hold the value in advance. Further, the value of the maximum power Pmax may be a fixed numerical value, or may be a numerical value that the light source output control unit 2304 varies as necessary. In the latter case, control such as lowering the value of Pmax is possible in order to reduce power consumption.

(Step 2707)
In this step, the light source output control means 2304 compares the current specification power P of the light source temperature control means 1610 with the value of the maximum power Pmax. In general, the more heat is applied to the Peltier element, the more heat can be absorbed. In the state of Step 2707, the current temperature Tp of the light source coincides with the target temperature Tb. In this state, if the power used by the Peltier element 2201 does not reach the maximum power, the power used by the Peltier element 2201 even when the light source output is increased (when the light source heat generation amount is increased). By increasing P, the light source temperature may be maintained at the target temperature Tb. The higher the light source output, the larger the brightness and eye box can be displayed, and the driver's visibility is improved. When the power consumption P of the light source temperature control means 1610 does not reach the maximum power, the light source output control means 2304 executes the process of step 2705 to increase the light source output.

  By repeating the processing of steps 2701, 2702, 2704, 2706, and 2707, it becomes possible to increase the light source output while keeping the light source temperature constant.

  If the power usage P of the light source temperature control means 1610 and the maximum power Pmax match, the light source output control means 2304 terminates the processing and notifies the eye box shape control means 2305 of the value of the light source output.

  When comparing the current temperature Tp of the light source and the target temperature Tb, a certain error may be allowed. For example, even if the current temperature of the light source is 30 ° C. and the target temperature is 31 ° C., an error of 1 ° C. may be allowed and the values of Tp and Tb may be regarded as the same. In this case, the cost of controlling the light source temperature can be reduced.

[Step 2507] (Adjust eye box size)
In this step, the eye box shape control means 2305 performs processing for changing the eye box shape according to the change in the light source output.

  The relationship between the luminance of the display image displayed in the HUD, the display image size (area), the eye box size, and the light source output can be expressed by Equation 5. When the light source output has been reduced in the previous step 2506, it can be seen from the relationship of Equation 5 that the numerical value of at least one item among the luminance, the display image size, and the eye box size is reduced. In a normal HUD, the display image size and the eye box size are not changed, so that when the light source output is reduced, the luminance of the display image displayed on the driver is reduced. In the case of a display device that displays outdoors such as HUD, it is desirable that the luminance is higher from the viewpoint of visibility. Therefore, in this embodiment, the eye box shape control means 2305 changes the shape of the eye box 108 to reduce the eye box size and prevent the brightness of the display image from being lowered.

  FIG. 28 shows a detailed flow of processing performed by the eyebox shape control means 2305 in the present embodiment. The light source output can be controlled by performing the processing of steps 2801 to 2805 shown in FIG. Hereinafter, details of the eye box shape control in this step will be described based on processing flows 2801 to 2805 shown in FIG.

(Step 2801)
In this step, the eye box shape control means 2305 calculates the current brightness Kp of the display image. In the present embodiment, the eye box shape control means 2305 has a light source output value acquired from the light source output control means 2304, a current eye box size value held by the eye box shape control means 2305, and a constant A. The brightness of the display image is calculated using the value of. Formula 6 for calculating the brightness of the display image is shown in Equation 6. Here, the constant A is a constant for calculating the luminance from the light source output and the eye box size. For example, the value of the reciprocal of the display image size is set.

  The constant A may be set to a value other than the reciprocal of the display image size in consideration of the magnification of the optical system. In this case, it is possible to calculate the luminance of the display image in consideration of the HUD optical system.

(Step 2802)
In this step, the eye box shape control means 2305 compares the current brightness Kp calculated in the previous step 2801 with the numerical value of the minimum brightness Kmin held by the eye box shape control means 2305. If the current brightness Kp is smaller than the minimum brightness Kmin, the eye box shape control means 2305 performs the process of step 2803 to reduce the eye box size. In other cases, the process of step 2804 is performed.

  Note that the value of the minimum luminance Kmin may be a fixed numerical value, or may be a numerical value that is changed by the eyebox shape control means 2305 as necessary. In the latter case, the value of Kmin is changed according to the surrounding environment, and for example, during the day when the display is difficult to see, the value of the optimum luminance Kmin is increased, thereby making it possible to improve the driver's visibility.

(Step 2803)
In this step, the eye box shape control means 2305 changes the eye box shape in order to reduce the eye box size.

  In the present embodiment, the eyebox size is changed by changing the diffusion angle of the display light from the screen 801. FIG. 29 shows the relationship between the diffusion angle of display light from the screen 801 and the size of the eye box. 2901 in FIG. 29 is a case where the diffusion angle of the display light from the screen 801 is large. At this time, the display light diffused on the screen 801 is greatly spread, so that the size of the eye box 108 is widened. On the other hand, reference numeral 2902 in FIG. 29 shows a case where the diffusion angle of the display light from the screen 801 is small. At this time, since the spread of the display light diffused on the screen 801 is small, the size of the eye box 108 becomes narrow. Therefore, the size of the eye box 108 can be changed by changing the diffusion performance of the screen 801 at the position where the display light is incident on the screen 801.

  30 and 31 show examples of the diffusion characteristics of the screen 801 and the projection of display light onto the screen 801 in this embodiment. A 3001 screen 801 in FIG. 30 is a portion where the diffusion angle of display light is large, and 3003 is a portion where the diffusion angle of display light is small in the screen 801. Reference numeral 3003 in FIG. 30 denotes a projection area where display light from the display unit 103 is projected on the screen 801. In the example of FIG. 30, all the display light is projected onto a portion 3001 where the diffusion angle of the display light becomes large. When displaying in this part, the eye box becomes large. An example of the eye box at this time is shown in FIG. FIG. 32 is a front view of the positional relationship between the eyeball 3201 of the driver 107 and the eye box 108. At this time, both eyes of the driver are housed in the eye box 108, and the display image can be visually recognized. Further, since the size of the eye box 108 in the vertical direction is sufficiently large, even when the driver moves his / her head up and down, the eyeball 3201 of the driver stays in the eye box 108 and the driver may continue to visually recognize the display image. It becomes possible.

  In the example of FIG. 31, all the display light is projected onto a portion 3002 where the diffusion angle of the display light becomes small. When displaying in this part, the eye box becomes smaller. An example of the eye box at this time is shown in FIG. FIG. 33 is a front view of the positional relationship between the eyeball 3201 of the driver 107 and the eye box 108, as in FIG. Since the size of the eye box 108 in the vertical direction is smaller than that in FIG. 32, when the driver 107 moves his head greatly, the possibility that the driver's eyeball 3201 is detached from the eye box 108 increases. However, since the eyebox size is small, the brightness of the display image is higher than that in the state of FIG. 32 as shown in Equation 6 above, and the driver 107 can visually recognize a bright display. FIG. 34 shows a case where the projected region 3003 of the display image extends over a portion 3001 having a large diffusion angle and a portion 3002 having a small diffusion angle on the screen 801. The shape of the eye box at this time is shown in FIG. 351 shown in FIG. 35 is an eye box formed by pixels projected onto the region 3001 on the screen 801 having a large diffusion angle, and 3502 is a pixel projected onto the region 3002 on the screen 801 having a small diffusion angle. Shows an eye box formed by. As shown in this figure, the shape of the eye box differs between the right half and the left half of the screen. The eye box is wide up and down with respect to one side of the screen, and the eye box is narrow with respect to the other side of the screen. With such an eye box, even if the driver moves his head greatly, the eye area of the eyebox is wide and the driver's eyes stay inside the eye box, so the driver can see half of the displayed image with one eye. can do. At the same time, since the eye box corresponding to the other side of the screen has a reduced eye box size, the brightness of the display image can be improved even when the light source output is low. In the example of FIG. 35, when the size of the eye box differs depending on the pixel of the screen, the average value of the eye box formed by each pixel is treated as the eye box size in this embodiment.

  In the present embodiment, the screen 801 is constituted by the fly-eye mirror as described above, and has the structure shown in FIGS. At this time, the diffusion angle of the display light from the screen 801 has a relationship expressed by Equation 7 when the curvature radius R of the micromirrors constituting the screen 801 and the diameter of the micromirrors are D. In the present embodiment, the diffusion angle of the display light is changed for each position on the screen 801 by changing the value of the curvature radius R of the micromirror according to the position of the screen 801.

  In this step 2803, the eye box shape control means 2305 calculates the eye box size Sa after the shape change by using the calculation formula shown by the equation 8 from the light source output value and the minimum luminance value. Here, the constant A is the same as that shown in Equation 6 above, and a description thereof will be omitted. The eye box shape control means 2305 moves the projection area 3003 of the display image on the screen 801 so that the eye box size becomes the calculated value Sa. In the present embodiment, the eye box shape control means 2305 has means for moving the position of the screen 801 left and right, and changes the projection range of the display light incident on the screen 801 by moving the screen 801 left and right.

  In this embodiment, in order to determine the position of the projected area 3003 of the display image on the screen 801, the eye box shape control means 2305 uses data representing the relationship between the position on the screen and the eye box size as shown in FIG. Have. FIG. 36 shows the relationship between the horizontal position (X) on the screen and the eye box size (F (X)) when display light is projected and diffused at that position. For example, when the display light is projected on the left end (XL) of the screen 801, the eye box size (F (XL)) is Y1, and when the display light is projected on the right end (XR) of the screen 801, the eye box The size (F (XR)) indicates Y2. In this embodiment, the eye box shape control means 2305 is the average value of the values obtained by integrating the eye box size F (X) for the section from the left end X1 to the right end X2 of the projection area 3003 (the difference between the integrated value X2 and X1). (Divided by 1) is treated as the eyebox size Sb. The eye box shape control means 2305 determines the position of the projection region 3003 and moves the position of the screen 801 so that the value of Sb matches the aforementioned Sa (eye box size for realizing the minimum luminance Kmin). .

  Note that the diffusion characteristic of the screen 801 does not have a constant diffusion angle for each region as shown in FIG. 36, and the diffusion angle may change continuously. An example of this is shown in FIG. Even in this case, the value of the eye box size Sb can be obtained by integrating the value of F (X) in the section from the left end to the right end of the projection area 3003 of the display image. In this case, the eye box size can be changed in more detail.

  Instead of moving the screen 801 left and right, the projection range on the screen 801 may be changed by changing the direction in which the display light is projected from the display unit 103. In this case, the direction in which the display light is projected can be changed by tilting the entire display unit 103. In this case, since it is not necessary to move the position of the screen 801, the optical system of the HUD optical unit 102 can be reduced in size.

  When changing the projection direction of the display light from the display means 103, a deflection element for changing the direction of the light is arranged at a portion where the display means 103 emits the display light instead of changing the whole direction of the display means 103. You may use the method to do. As the deflection element, an electro-optic element, an acousto-optic element, or a variable hologram element (an element capable of recording a diffraction grating on a liquid crystal element and controlling a diffraction function by voltage) can be used. In this case, the display position of the image on the screen 801 can be changed without using a movable part that moves the display unit 103.

  Note that a method of changing the position of the display image on the screen 801 by changing the display position of the image on the display element 1607 of the display means 103 may be used. In this case, it is not necessary to move parts (such as the screen 801), so that the optical system can be downsized.

(Step 2804)
In this step, the eye box shape control means 2305 compares the current brightness Kp calculated in the previous step 2801 with the maximum brightness Kmax held by the eye box shape control means 2305. When the current brightness Kp is larger than the maximum brightness Kmax, the eye box shape control means 2305 performs the process of step 2805 to enlarge the eye box size. When the eye box is wide, it is difficult for the eyeball to come off the eye box when the driver's head moves, so that the driver's visibility is improved.

  Note that the value of the maximum luminance Kmax may be a fixed numerical value, or may be a numerical value that is changed by the eyebox shape control means 2305 as necessary. In the latter case, the value of Kmax is changed according to the surrounding environment. For example, during the daytime when the display is difficult to see, the value of the maximum luminance Kmax is increased, thereby improving the driver's visibility.

(Step 2805)
In this step, the eye box shape control means 2305 changes the eye box shape in order to enlarge the eye box size.

  In this step 2805, the eye box shape control means 2305 calculates the eye box size Sa after the shape change by using the calculation formula shown by the formula 9 from the light source output value and the maximum luminance value. Here, the constant A is the same as that shown in Equation 6 above, and a description thereof will be omitted. The eye box shape control means 2305 moves the projection area 3003 of the display image on the screen 801 so that the eye box size becomes the calculated value Sa. In the present embodiment, the eye box shape control means 2305 has means for moving the position of the screen 801 left and right, and changes the projection range of the display light incident on the screen 801 by moving the screen 801 left and right.

  In this step as well as step 2803, the eye box size Sb corresponding to the position on the screen 801 of the projection area 3003 is calculated from the data representing the relationship between the position on the screen and the eye box size as shown in FIG. The position of the projection region 3003 on the screen 801 is determined so that the value of Sb matches the value of Ss, and the screen 801 is moved. Note that the calculation method of Sb is the same as that described in step 2803.

  In step 2507, it is possible to change the eye box shape by executing the processing of steps 2801 to 2805 described above.

  In the present embodiment, the display light from the screen 801 is directly incident on the windshield 106. However, a folding mirror may be disposed between the screen 801 and the windshield 106. In this case, it becomes possible to bend the optical path of the optical system, which facilitates downsizing.

  In the present embodiment, the diffusion performance of the screen 801 changes depending on the position in the horizontal direction. However, the diffusion performance may be changed according to the position of the screen 801 in the vertical direction. This example is shown in FIG. In the screen 801 of FIG. 38, a region 3001 with a large diffusion angle constitutes the upper half of the screen, and a region 3002 with a small diffusion angle forms the half of the screen, and the position of the projected region 3003 of the display image is moved in the vertical direction of the screen. This makes it possible to change the shape of the eye box.

  As shown in FIG. 37, when the shape of the eye box is not uniform on the left and right, the luminance decreases because the display light spreads in the region where the eye box size is large (left side in the example of FIG. 37). In order to prevent this, the display image displayed on the display unit 103 may be set so that the luminance of the pixel in the portion with the large vertical size of the eye box is higher than the luminance of the pixel in the portion with the small eye box size. . In this case, the brightness of the display image can be made uniform even when the eyebox shape is nonuniform.

  Note that instead of changing the diffusion performance of the screen 801 for each position on the screen, a method of arranging a diffusion sheet for changing the diffusion angle of display light on the optical path from the screen 801 to the windshield 106 may be used. good. This example is shown in FIG. 3901 of FIG. 39 is a transparent sheet which transmits light, and has the capability of changing the diffusion angle of the light transmitted through the sheet. The diffusion sheet 3901 is designed to have different diffusion performance depending on the position on the sheet, and the eyebox shape control means 2305 moves the diffusion sheet 3901 instead of moving the screen 801 in step 2507 described above. By doing so, the shape of the eye box may be changed. In this case, since the diffusion sheet can be formed of a hologram or the like, there is an effect that the manufacturing is easier than the case of forming the screen 801 with a minute mirror.

  Even when the screen 801 is not moved, a configuration in which the diffusion angle is changed according to the position on the screen may be used. 40 and 41 show examples of the diffusion characteristics of the screen 801 in which the eye box size of the pixel at the center of the screen is increased. In these examples, widening the eye box in the center of the screen where important information is easy to display makes it easier for the driver to see important information, and by reducing the pixel eye box at the edge of the screen. The eye box size is reduced, and the value of the light source output necessary for display is reduced. Eyebox size is getting smaller. As shown in Equation 5, the smaller the eyebox size, the smaller the light source output necessary to achieve a certain luminance. Therefore, by using these screens 801, a bright display can be performed with a smaller light source output. It becomes possible.

  In this embodiment, the output wavelength of the light source is changed by controlling the light source temperature, but a plurality of light sources having different wavelengths are prepared for each RGB, and the RGB wavelength is changed by switching the light source to be used. A method may be used. In this case, it becomes easier to control the light source temperature.

  In the present embodiment, for the sake of simplicity, the explanation has been given by taking the light source temperature and output change for one of the RGB light source wavelengths as an example. However, the same processing is performed for light sources of other wavelengths. May be.

(Embodiment 2)
In this embodiment, even when the incident angle of the display light to the narrow band filter is changed in order to change the eye box position, the output wavelength of the light source is changed by utilizing the temperature dependence of the light source wavelength. An HMD capable of preventing the occurrence of double images will be described.

  Similar to the HUD shown in the first embodiment, in the HMD, it is necessary to change the eyebox position according to the width of the user's eyes and the size of the face. Therefore, it is possible to prevent double images when changing the eyebox position by controlling the wavelength of the light source in the same manner as the HUD.

  FIG. 43 shows a configuration diagram of a transmissive display device in this embodiment. In addition, about the component same as Embodiment 1, the same code | symbol is used and description is abbreviate | omitted.

  Reference numeral 4301 denotes a spectacle frame which is a main body of the transmissive display device in this embodiment. The display means 103, the screen 801, and the control means 802 are installed on the vine portion of the spectacle frame 4301. With this shape, it is not necessary to provide a large optical system / mechanism in front of the user's eyes like a conventional HMD, and the appearance of the display device can be improved.

  Reference numeral 4302 denotes a spectacle lens, which is adjusted in power according to the user's visual acuity. The narrow band filter 401 is installed on the surface of the eyeglass lens 4302 and reflects display light from the screen 801 toward the user's eyeball without impairing the user's visual acuity.

  The eyebox position changing means 803 may be integrated with the spectacle frame 4301 or may be separate from the spectacle frame as shown in FIG. In this case, the driver can operate the eyebox position changing means 801 by holding it like a remote controller. When the eyebox position changing unit 803 is separate from the eyeglass frame 4301, data communication is enabled by connecting to the control unit 802 wirelessly or by wire.

  Also in the present embodiment, the wavelength control of the display light for the narrow band filter 401 is performed with respect to the wavelength change of the light source. However, the contents of the processing are the same as those in the first embodiment, and thus the description thereof is omitted.

  The embodiment described so far is merely an example, and various forms can be adopted without departing from the gist of the present invention.

  The transmissive display device according to the present invention has narrow band reflecting means for reflecting a specific wavelength, and can be applied to uses such as a display device, a display system, a display method, and a display program.

101 Equipment (vehicle body, etc.) where a transmissive display device is installed
105, 1702 Opening 106 Windshield 107 Driver 102 Optical unit 103 Display means 104 Deflection means 401 Narrow band filter 801 Screen 802 Control means 1601 Red laser light source 1602 Blue laser light source 1603 Green laser light source 1604 Collimator

Claims (18)

A light source that outputs light;
Display means for receiving light emitted from the light source to form an image;
Within the visible light wavelength range, it has a characteristic of reflecting light in a part of the wavelength range with high reflectance and transmitting light in the other wavelength range, and reflects the light from the display means toward the user. Narrowband reflection means;
The light from the display means comprises wavelength control means for changing the wavelength output from the light source in accordance with a change in the incident angle incident on the narrowband reflecting means,
A transmission type display apparatus, wherein a reflection wavelength range, which is a wavelength range of light reflected by the narrowband reflecting means, varies depending on an incident angle of light with respect to the narrowband reflecting means. 2. The transmissive display device according to claim 1, wherein the narrow band reflecting means is a multilayer filter or a rugate filter made of a low refractive index material and a high refractive index material. The wavelength control means, when the incident angle of the light incident on the narrowband reflecting means is small, the output wavelength of the light source so that the output wavelength of the light source is included in the reflected wavelength range of the narrowband reflecting means Lengthen the
When the incident angle of the light incident on the narrowband reflecting means is large, the output wavelength of the light source is shortened so that the output wavelength of the light source is included in the reflected wavelength range of the narrowband reflecting means. The transmissive display device according to claim 2. The transmissive display device according to claim 3, wherein the light source is a laser light source, and the wavelength of light to be output becomes longer as the light source temperature is higher. The wavelength control means, a temperature control means for changing a light source temperature in order to control an output wavelength of the light source;
The transmissive display device according to claim 4, further comprising: a light source output control unit that changes a light source output in order to control a heat generation amount of the light source. The light source comprises at least two or more individual light sources that output different wavelengths,
The narrowband reflecting means is configured by laminating an individual multilayer filter that reflects an output wavelength from the individual light source, for each of the two or more individual light sources,
The average refractive index of each individual multilayer filter is set so that the amount of change in reflection wavelength due to the change in the incident angle of the individual multilayer filter is the same for each individual multilayer filter. Item 6. The transmissive display device according to Item 5. Having eye box shape control means for changing the shape of the eye box that allows the user to visually recognize the image;
6. The transmissive display device according to claim 5, wherein the eye box shape control means changes the eye box shape so that the size of the eye box decreases as the light source output of the light source decreases. Deflecting means for deflecting the display light emitted from the display means toward the narrow-band reflecting means;
The deflection unit has a diffusion performance of diffusing incident display light in a specific direction, and the deflection unit has a diffusion angle, which is an angle at which incident display light is diffused, for each position on the deflection unit. The transmissive display device according to claim 7, which is different. 9. The eye box shape control means changes the eye box shape by changing a position of a projection range in which display light emitted from the display means is projected on the deflection means. The transmissive display device described in 1. 10. The transmission type display according to claim 9, wherein the diffusion angle of the display light incident on the deflection unit is different in the size of the diffusion angle between a right region of the deflection unit and a left region of the deflection unit. apparatus. The eyebox shape control means includes
The transmissive display device according to claim 10, wherein the position of the projection range of the display light on the deflection unit is changed by moving the position of the deflection unit. The display means has display light deflection means for changing the direction of the emitted display light,
The eye box shape control means changes the position of the projection range of the display image on the deflection means by changing the incident angle of the display light incident on the deflection means from the display means by the display light deflection means. The transmissive display device according to claim 10. The transmissive display device according to claim 12, wherein the display light deflection unit changes an emission direction of the display light by changing a direction of the display unit. 13. The display light deflecting unit is a dynamic hologram that is installed in an opening portion through which the display unit emits display light, and can switch a deflection function by applying a voltage. The transmissive display device described. The transmissive display according to claim 9, wherein the deflecting means is a fly-eye mirror composed of a minute concave mirror, and the radius of curvature of each fly-eye mirror varies depending on the position on the deflecting means. apparatus. The diffusion angle, which is the range in which the light diffused at the point on the deflection means spreads, is the amount of change in the reflection wavelength when the incident angle to the narrow band reflection means is changed by the value of the diffusion angle. The transmissive display device according to claim 9, wherein the transmissive display device is smaller than the width of the reflection wavelength range of the means. 9. The transmissive display device according to claim 8, wherein the deflecting unit has the largest diffusion angle of the display light incident on the center of the deflecting unit. A diffusion sheet that changes a diffusion angle of display light is provided between the deflection unit and the narrowband reflection unit, and the diffusion sheet has a different degree of change in the diffusion angle of the display light transmitted through the sheet depending on the position on the sheet. Has characteristics,
The transmissive display device according to claim 7, wherein the eye box shape control unit changes the eye box shape by changing a position of the diffusion sheet.

Images