JP4581180B2 - Virtual image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a virtual image display device that enables a virtual image to be observed with a single eye or with both left and right eyes.
[0002]
[Prior art]
Conventionally, virtual image display devices have been proposed. As shown in FIG. 15, such a virtual image display device is configured to observe an output image of an image display element (LCD panel) 101 through a magnifying optical system 102 for displaying a virtual image. That is, such a virtual image display device spatially modulates the light emitted from the light source 103 by the image display element 101, and displays an image by using a magnifying optical system 102 such as a concave mirror optical system or a convex lens optical system. The display image of the element 101 is formed as a virtual image 104.
[0003]
Such a virtual image display device is put into practical use as a so-called head mounted display (HMD), a head-up display (HUD), or a so-called view finder. In the virtual image display device, the wider the region where the virtual image can be observed, the easier it is to see. However, since the pupil diameter of the optical system is small in a practical virtual image display device, it can be observed within an observable region by providing an eye width adjustment mechanism or fixing it to the head as a spectacle type or a helmet type. The observer's pupil is present.
[0004]
However, development of a virtual image display device that can easily observe a virtual image without being fixed to the head or the like is desired. For this purpose, it is necessary to increase the pupil diameter of the virtual image display device. It is difficult to sufficiently increase the pupil diameter of the virtual image display device because the size of the optical system is limited and the angle of light emitted from the virtual image display device cannot be increased.
[0005]
As the image display element, a transmissive light valve, a reflective light valve, a CRT (cathode ray tube) or the like is used. Many conventional virtual image display devices are configured using a transmissive light valve.
[0006]
2. Description of the Related Art In recent years, a reflective liquid crystal light valve using a crystalline Si (silicon) substrate has been developed in developing a small and high-resolution virtual image display device. This reflection type liquid crystal light valve is characterized in that a CMOS circuit is formed on a Si substrate, a reflecting mirror is formed thereon, and a liquid crystal is sandwiched between them. In such a reflective liquid crystal light valve, an improvement in aperture ratio is realized, and furthermore, since a Si-based manufacturing process can be adopted, the design rule can be made fine and it is suitable for realizing high resolution.
[0007]
The configuration of a virtual image display device using such a reflective light valve is described in, for example, US Pat. No. 5,808,800. In this virtual image display device, as shown in FIG. 16, the light beam emitted from the light source 103 is converted into a parallel light beam by the collimator lens 105 and is incident on the polarization beam splitter 106 made of glass or the like. In 107, an S-polarized component and a P-polarized component are divided. In this polarization beam splitter 106, the S-polarized component is reflected by the reflective film 107 and enters the reflective light valve 108.
[0008]
The reflective light valve 108 modulates the polarization state of light according to the electrical signal of the video apparatus. That is, the light beam incident on the reflective light valve 108 is modulated by the reflective light valve 108, and light corresponding to the video signal is reflected. The light beam reflected by the reflective light valve 108 passes through a refractive lens 109 serving as a magnifying optical system, is magnified, and is imaged by the observer's pupil 110.
[0009]
This virtual image display device is characterized in that the pupil diameter can be increased by forming the light source image on the pupil to effectively use the amount of light emitted from the light source and increasing the number of light sources. .
[0010]
[Problems to be solved by the invention]
Incidentally, in the virtual image display apparatus in which the light source image is formed on the pupil as described above, the number of light sources must be increased in order to increase the pupil diameter. Increasing the number of light sources leads to an increase in power consumption, an increase in the size of the apparatus, and an increase in cost, which is not realistic as a countermeasure for increasing the pupil diameter.
[0011]
In addition, in order to uniformly irradiate the light valve with the image of the light source, an illumination optical system configured to make the emitted light uniform using a fly-eye lens or the like must be used. Therefore, the illumination optical system becomes complicated and large.
[0012]
Furthermore, even if such an illumination optical system is used, there is a possibility that uneven color or uneven brightness may occur due to slight movement of the eyes.
[0013]
Therefore, the present invention has been proposed in view of the above-described circumstances, and is used when observing an image displayed by the image display element as a virtual image while maintaining high use efficiency of illumination light for the image display element. The occurrence of uneven brightness and intensity due to the movement of the pupil can be prevented, and a uniform image in terms of brightness and chromaticity can be displayed. An object of the present invention is to provide a virtual image display device that is made large and further has a simplified configuration of an illumination optical system.
[0014]
[Means for Solving the Problems]
In order to solve the above-described problems, a virtual image display device according to the present invention has a planar light emitting unit. , A light source that emits diffused light from each point of the light emitting unit; A splitter that polarizes light emitted from the light source, and is incident through the splitter. Image display element for modulating and emitting light according to display image, and image display element Modulated by And an magnifying optical system that collects light and forms a virtual image of the display image.
[0015]
In this virtual image display device, the light emitting portion of the light source is arranged in a conjugate region via the magnification optical system with respect to the region where the virtual image of the display image formed by the magnification optical system can be observed. It is characterized by that.
[0016]
Further, in this virtual image display device, the light-emitting portion of the light source can observe the virtual image of the display image formed by the magnifying optical system, and light from the entire surface of the image display element enters the entire pupil aperture of the observer It is characterized in that it is arranged in a conjugate region with respect to the region to be formed via the magnifying optical system.
[0017]
Further, in this virtual image display device, the light emitting portion of the light source is arranged at a conjugate position via the magnifying optical system with respect to the center position of the region where the virtual image of the display image formed by the magnifying optical system can be observed. It is characterized by that.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0019]
As shown in FIG. 1, the virtual image display apparatus according to the present invention is configured by using an optical system in which the reflecting surface 2 of the polarizing beam splitter 1 serving as a light beam splitting surface is arranged at 45 ° with respect to the optical axis. Can do.
[0020]
As shown in FIG. 2, the virtual image display device includes a light source including light emitting elements (LED) 3 of three colors of R (red), G (green), and B (blue) and a side edge type light guide plate 4. Yes. In this light source, the light beam emitted from the light emitting element 3 enters the side edge type light guide plate 4, is diffused and mixed in the side edge type light guide plate 4, and is emitted from the emission surface 5. The side edge type light guide plate 4 is formed in a substantially flat plate shape, and has a wedge shape in which the thickness on one side (for example, 3 mm) is thicker than the thickness on the other side (for example, 0.3 mm). . The light flux from the light emitting element 3 is incident from one side surface portion of the side edge type light guide plate 4. The exit surface 5 of the side edge type light guide plate 4 is a portion corresponding to a main surface portion of the side edge type light guide plate 4 and has substantially the same size and shape as an image display surface of a reflection type light valve 6 described later. . The emission surface 5 is a planar light emitting portion that emits diffused light from each point on the surface.
[0021]
A reflective film is attached to one side surface portion of the side edge type light guide plate 4 and side surface portions and back surface portions other than the emission surface 5.
[0022]
The light beam emitted from the emission surface 5 of the side edge type light guide plate 4 enters the polarization beam splitter 1 and reaches the reflection surface 2 as shown in FIG. On the reflecting surface 2, the light beam from the light source is separated into an S-polarized component and a P-polarized component. That is, on the reflecting surface 2, the S-polarized component is reflected and the P-polarized component is transmitted. The light beam reflected by the reflecting surface 2 enters the reflective light valve 6 that is an image display element.
[0023]
The reflection type light valve 6 modulates the polarization state of incident light in accordance with an electric signal of an image device (not shown). That is, the light beam incident on the reflective light valve 6 is modulated by the reflective light valve 6 and light corresponding to the video signal is reflected. The light beam modulated and reflected by the reflective light valve 6 passes through the magnifying optical system including the eyepiece lens 7, passes through the pupil 8 of the observer, and forms an image on the eye.
[0024]
Here, the eyepiece lens 7 is used as the magnifying optical system, but a concave mirror optical system or an optical system having both a concave mirror and an eyepiece lens may be used.
[0025]
In FIG. 1, the ray tracing of the light emitted from the emission surface 5 is indicated by a solid line, and the ray tracing emitted from the reflective light valve 6 is indicated by a broken line.
[0026]
When the positional relationship between the image display surface of the reflection type light valve 6 and the emission surface 5 of the side edge type light guide plate 4 which is a light emitting portion is vertical as shown in FIG. In order to make the illumination light emitted uniform, it is necessary to illuminate telecentrically. For this purpose, it is desirable that the exit surface 5 of the side edge type light guide plate 4 has a size larger than the effective area of the image display of the reflective light valve 6.
[0027]
In this virtual image display device, the exit surface 5 of the side edge type light guide plate 4 and the position of the observer's pupil 8 are arranged in a conjugate positional relationship. As a result, in this virtual image display device, it is possible to observe a video display having no luminance unevenness and color unevenness.
[0028]
Next, the light source constituting the virtual image display device will be described in more detail.
[0029]
In this light source, the side edge type light guide plate 4 is used to control the angle of the light beam that illuminates the reflection type light valve. As described above, the side edge type light guide plate is a semi-transparent body having a wedge shape, but in general, the backlight of a direct view type liquid crystal panel used in a monitor display such as a so-called personal computer is used. Widely used as a light guide plate.
[0030]
As a material of the side edge type light guide plate 4, an acrylic resin (Polymethylmethacrylate (PMMA)) or a light scattering polymer can be used. The light scattering polymer is, for example, a material obtained by adding a small amount of transparent impurities having different refractive indexes to an acrylic resin or the like, and is a material that enables control of light emission characteristics and has a large color mixing effect. When a light emitting diode (LED) or a laser diode (LD) is used as the light emitting element, it is necessary to mix colors in the side edge type light guide plate. Therefore, it is effective to use a light scattering polymer as the material.
[0031]
In this light source, as shown in FIG. 3, the light emitting elements 3 of R, G, and B colors are configured as “chip type LEDs” in one package. By bringing these light emitting elements 3 into close contact with one side surface portion of the side edge type light guide plate 4, utilization efficiency of light emitted from the light emitting elements is improved. Furthermore, if the space between the side edge type light guide plate 4 and the surface of the light emitting element 3 is filled with a solvent having a refractive index close to the refractive index of the epoxy resin that is the lens surface of the light emitting element, the light utilization efficiency is further improved. be able to.
[0032]
A white or silver reflective film is used as the reflective film to be attached to the surfaces other than the incident surface and the exit surface of the side edge type light guide plate. In addition, a prism sheet for controlling the diffusion angle of the emitted light beam is attached to the exit surface 5 of the side edge type light guide plate. With this prism sheet, the divergence angle of the light beam emitted from the exit surface 5 is 10 ° to 30 ° at half value.
[0033]
As shown in FIG. 4, the luminous flux emitted from the side-edge type light guide plate 4 has different divergence angles in the θ1 direction and the θ2 direction, that is, the cross-sectional shape of the luminous flux is elliptical. Here, as shown in FIG. 5, θ 1 is an angle that is parallel to the emission surface 5 and has a direction from the light emitting element 3 toward the side edge type light guide plate 4 as an axis. Further, as shown in FIG. 5, θ2 is an angle about the direction parallel to the emission surface 5 and perpendicular to θ1. FIG. 4 shows that the divergence angle in the θ1 direction is wider than the divergence angle in the θ2 direction. The data shown in FIG. 4 is obtained when the side edge type light guide plate 4 is formed of a light scattering polymer. When the light-emitting element is a laser diode, the light beam itself emitted from the light-emitting element has a large divergence angle, and the divergence angle varies depending on the direction, and the cross-section of the light beam is elliptical.
[0034]
In addition, the light emission part in this light source may be ground glass placed immediately after the light emitting element.
[0035]
Next, the range in which the virtual image of the image displayed by the reflective light valve 6 that is a virtual image display element can be observed, that is, the relationship between the pupil diameter of the optical system and the angle of the light beam emitted from the reflective light valve 6 will be described. To do.
[0036]
First, for simplification of explanation, it is assumed that the distance between the reflective light valve 6 and the eyepiece lens 7 is equal to the focal length f of the eyepiece lens 7 as shown in FIGS. Then, the vertical divergence angle of the light beam emitted from the reflective light valve 6 is 2ω as shown in FIG. ₁ And the horizontal divergence angle is 2ω as shown in FIG. ₂ And Further, the pupil diameter of the optical system capable of familiarizing the virtual image is Φ1 in the vertical direction as shown in FIG. 6, and Φ2 in the horizontal direction (left and right direction) as shown in FIG. To do.
[0037]
Reflective light valve 6 to 2ω ₁ 2ω ₂ The light beam emitted at the divergence angle passes through the eyepiece lens 7 at the focal length f, enters the eye through the observer's pupil 8, and forms an image. The pupil diameters Φ1 and Φ2 of the optical system are calculated from the following relational expressions in consideration of the arrangement of the optical systems shown in FIGS.
[0038]
Φ1 = 2ftan (ω ₁ )
Φ2 = 2ftan (ω ₂ )
Therefore, in order to increase the pupil diameters Φ1 and Φ2, the focal length f of the eyepiece lens 7 is increased, or the divergence angle 2ω of the light beam emitted from the reflective light valve 6 is increased. ₁ 2ω ₂ Need to be larger.
[0039]
However, in the virtual image display device in which the downsizing of the optical system is required, the focal length f of the eyepiece lens 7 cannot be increased, so that the divergence angle 2ω of the bundle emitted from the reflective light valve 6 is increased. ₁ 2ω ₂ Need to be larger.
[0040]
Here, using the side edge type light guide plate or the direction dependency of the divergence angle of the light emitted from the light emitting element, the side edge type guide is used in the direction of large pupil movement, usually in the horizontal direction (left and right direction). By matching the direction in which the divergence angle of the light emitted from the light plate or the light emitting element is large, the distance that the pupil can move practically can be increased. In addition, if a general video display device is of the “NTSC system”, the aspect ratio of the image is 4: 3, and if of the “HD system”, the aspect ratio of the image is 16: 9. From this point of view, the direction in which the amount of movement of the pupil is large is the horizontal direction (left-right direction).
[0041]
This will be described with reference to FIG. 6 and FIG. 7. The side edge type light guide plate or the one having the wider divergence angle of the emitted light from the light emitting element indicates the longer side (longitudinal) direction of the display image of the video display element. If placed in ω ₂ > Ω ₁ As a result, the relationship of Φ1> Φ2 occurs, and it can be seen that the pupil diameter can be increased in the long side (longitudinal) direction of the display image.
[0042]
In addition, the eyeglass-type binocular virtual image display device does not have an eye width adjustment function in order to simplify the device configuration. In general, the human eye width varies from 57 mm to 67 mm. The eyeglass-type binocular virtual image display device is designed to match the average human eye width of about 60 mm. If the pupil diameter is not increased in the horizontal direction (left-right direction), The device cannot be used. Therefore, in the eyeglass-type binocular virtual image display device, the side edge type light guide plate or the direction in which the divergence angle of the light emitted from the light emitting element is large may be arranged in accordance with the horizontal direction in which the amount of change in eye width is large.
[0043]
Next, a virtual image observable region in this virtual image observation apparatus will be described. When using this virtual image observation apparatus, it is desirable for the observer to bring his eyes to the pupil position in the optical design. However, in practice, the observer can observe a virtual image even if the eye is not accurately located at the pupil position in the optical design. Here, a spatial range in which the entire surface of the image displayed by the image display element can be observed even if the observer moves his / her eyes is referred to as a “virtual image observable region”.
[0044]
By locating the eyes in a region where all the light beams that have passed through the image display area of the video display element overlap through the magnifying optical system, the entire image displayed by the image display element can be observed. That is, as shown in FIGS. 8 and 9, a region where all the light beams that have passed through the image display area of the video display element overlap through the magnifying optical system is a virtual image observable region V.
[0045]
8 and 9 show cross-sectional views of ray tracing of the light beam emitted from the image display element. For convenience, it is a diagram when the virtual image distance is set to infinity. The light beam emitted from the image display element passes through the magnifying optical system, passes through the pupil position of the observer, and forms an image on the eye. As shown in FIG. 8, the virtual image observable region V is a region where the light beam emitted from the uppermost part of the image display element and the light beam emitted from the lowermost part overlap each other via the magnifying optical system, that is, FIGS. In FIG. 5, the area is indicated by a rectangle surrounded by a black line.
[0046]
Actually, since the video display element is a display element that displays a two-dimensional image, the virtual image observable region V exists spatially and three-dimensionally. That is, along the optical axis from the position of the pupil determined by the optical design, a cone, an elliptical cone, or a polygonal pyramid with a shape (circle, ellipse, or square) determined by the aperture of the optical system on the bottom It becomes the area | region of the shape overlapped on. Here, when the angle of view is θ, the pupil diameter is Φ, and the distance along the optical axis is 2h, in the case of a design where the virtual image distance is infinite,
tan (θ / 2) = Φ / 2h
Is satisfied.
[0047]
The virtual image observable region V has a symmetrical shape along the optical axis from the optically designed pupil position when the virtual image distance is infinite, but the virtual image distance is designed to be a finite distance. In this case, the shape of the cone in the direction in which the light beam travels from the designed pupil position is not a symmetrical shape but a long shape.
[0048]
Next, the relationship between the pupil diameter and the virtual image observable region will be described. In the virtual image display device according to the present invention, the light emitting portion of the light source is arranged with a conjugate positional relationship with respect to the virtual image observable region via the magnifying optical system. That is, as shown in FIG. 10, a conjugate image through the magnifying optical system of the light emitting part of the light source is formed in the virtual image observable region.
[0049]
In FIG. 10, the position C, which is the position where the area of the cross section (observation cross section) cut perpendicular to the optical axis in the virtual image observable region is the largest, is a pupil position in optical design. Positions B positioned on both sides before and after this position C are the minimum size within the virtual image observable region where the size of the observation cross section can include a circle with a diameter of 3 mm corresponding to the pupil diameter of the observer, In the case of a rectangle, the position is a short side of 3 mm.
[0050]
Then, the position A in FIG. 10 corresponding to both the front and rear ends of the virtual image observable region starts to lose a part of the image of the image display element when it is away from the designed pupil position along the optical axis from this position. It is a position where it becomes impossible to observe.
[0051]
Next, as shown in FIGS. 11 and 12, an observation cross section indicated by a rectangle in FIGS. 11 and 12 in which a virtual image observable region is cut out by a plane perpendicular to the optical axis, and a human being indicated by a circle in FIGS. The relationship between the position of the pupil and the size of the pupil diameter will be described. In general, the human pupil diameter (pupil diameter) is small in a bright place and large in a dark place, but is about 3 mm to 8 mm. Here, the minimum value of 3 mm will be described as the pupil diameter.
[0052]
As for the pupil diameter and the size of the virtual image observable region cross section, as shown in FIG. 11, the virtual image observable region cross section becomes smaller from the pupil position on the optical design along with the movement of the eye along the optical axis. Here, as shown by I in FIG. 11, when there is a relationship that the length of the short side of the observation cross section is larger than the pupil diameter, the entire display area of the video display element can be observed. However, as indicated by II in FIG. 11, when the length of the short side of the observation cross section becomes smaller than the pupil diameter, the entire display area of the video display device can be observed, but the amount of light entering the pupil is small. The image that can be observed becomes dark. From this, position B in FIG. 10 corresponds to a positional relationship in which the short side of the observation cross section interrupts the pupil diameter, that is, a relationship indicated by I in FIG.
[0053]
As for the positional relationship between the pupil position and the observation cross section of the virtual image observable region, as shown in FIG. 12, as shown by (1) in FIG. The virtual image can be observed sufficiently. Then, as shown in (2) in FIG. 12, in the case where a part of the pupil protrudes from the observation cross section, the display area of the image display element is not lost, but the decrease in the amount of light around the image is observed. Is done. Then, as shown in (3) in FIG. 12, when the whole pupil is out of the observation section, the display area of the observable image display element is chipped, that is, the entire display area is observed at once. I can't do that.
[0054]
In this virtual image observation apparatus, the light source, the image display element, and the magnifying optical system are arranged so that the conjugate image of the light emitting part of the light source is located within the region where the observer can observe the virtual image. With such an arrangement, the entire screen displayed by the image display element can be observed without being lost.
[0055]
In addition, by arranging the light source, the image display element, and the magnifying optical system so that the conjugate image of the light emitting unit of the light source is a region containing the minimum human pupil diameter of 3 mm in the observer's virtual image observable region, The entire screen displayed by the image display element can be observed without missing, and a sufficient amount of light around the display area can be secured.
[0056]
Furthermore, by arranging the light source, the image display element, and the magnifying optical system so that the conjugate image of the light emitting portion of the light source is at a position where the area of the cross section perpendicular to the optical axis of the virtual image observable region of the observer is maximized Thus, the entire screen displayed by the image display device can be observed without loss, the amount of light around the display area can be sufficiently secured, and a large amount of eye movement in a direction perpendicular to the optical axis can be secured.
[0057]
As described above, in this virtual image observation apparatus, the observer can observe a uniform image in terms of luminance and chromaticity without luminance unevenness and color unevenness.
[0058]
And the virtual image display apparatus which concerns on this invention can be comprised using a concave mirror optical system as an expansion optical system, as shown in FIG.
[0059]
In this virtual image display device, the optical system includes three optical blocks 10, 11, and 12. The luminous flux emitted from the light emitting elements (LEDs) 3 of three colors of R (red), G (green), and B (blue) enters the side edge type light guide plate 4 and is diffused in the side edge light guide plate 4. The colors are mixed and exit from the emission surface 5 which becomes a light emitting part. The light beam emitted from the exit surface 5 enters the first optical block 10. The first optical block 10 is a prism formed in a triangular prism shape having three surfaces. A light beam from the side edge light guide plate 4 is incident from the first surface, and a polarization beam splitter is incident on the second surface. A film 10a is formed, and the third surface faces the reflective light valve 6 which is an image display element. The polarization beam splitter film 10a is made of a dielectric multilayer film or metal. The polarizing beam splitter film 10a serves as a light beam splitting surface and has an angle other than 45 ° with respect to the optical axis. The light beam from the side edge light guide plate 4 incident from the first surface is incident on the polarization beam splitter film 10a on the second surface, the S-polarized component is reflected, and the P-polarized component is transmitted. The S-polarized component reflected by the polarization beam splitter film 10 a is emitted from the second surface and enters the reflective light valve 6.
[0060]
The light beam (P-polarized component) modulated by the reflective light valve 6 reenters the first optical block 10 from the third surface, passes through the polarizing beam splitter film 10a on the second surface, 2 is incident on the second optical block 11. The second optical block 11 is a substantially triangular prism having three surfaces: an incident surface, a concave mirror portion 11a that is concave when viewed from within the second optical block 11, and a half mirror surface 11b. The light beam that has passed through the polarizing beam splitter film 10a of the first optical block 10 enters from the incident surface. The beam splitter film 10a of the first optical block 10 and the incident surface of the second optical block 11 are in close contact with each other. The light beam incident on the second optical block 11 is first reflected by the half mirror surface 11b, and then reflected by the concave mirror part 11a serving as the magnifying optical system to become a convergent light beam, and returns to the half mirror surface 11b again. The light passes through the half mirror surface 11 b and enters the third optical block 12.
[0061]
The third optical block 12 is a prism having an entrance surface and an exit surface. The incident surface of the third optical block 12 is in close contact with the half mirror surface 11 b of the second optical block 11. The light beam incident on the third optical block 12 is emitted from the emission surface. The exit surface is a lens surface that is concave when viewed from the outer side of the third optical block 12. The light beam emitted from the emission surface passes through the pupil 8 and forms an image on the eye.
[0062]
In FIG. 13, the ray tracing of the light emitted from the light emitting unit is indicated by a solid line, and the ray tracing emitted from the reflective light valve 6 is indicated by a wavy line.
[0063]
In this optical system, in order to increase the contrast of the display image, a polarizing plate for allowing only the S-polarized light component to pass is disposed between the side edge type light guide plate 4 and the first optical block 10. Further, if a polarizing plate that transmits only the P-polarized light component is disposed between the second optical block 11 and the third optical block 12, the optical characteristics can be further improved.
[0064]
Each of the optical blocks 10, 11, and 12 can be formed of an optical plastic such as acrylic resin (Polymethylmethacrylate (PMMA)), Zeonex (registered trademark), or optical glass. Further, the optical blocks 10, 11, and 12 are bonded with an optical adhesive so as to be in an optically continuous state. The feature of this optical system is that the direction of the light beam incident on the reflection type light valve 6 and the direction of the light beam reflected and emitted from the reflection type light valve 6 are different. For this reason, the light emission surface 5 which becomes the light emission part of a light source can be made smaller than the effective area of the image display of the reflection type light valve 6. FIG. Therefore, the entire optical system can be made compact.
[0065]
Furthermore, as shown in FIG. 14, the virtual image display device according to the present invention can also be configured using a transmissive light valve as an image display element.
[0066]
In this virtual image display device, light beams emitted from the light emitting elements (LEDs) 3 of R, G, and B colors enter the side edge type light guide plate 4 and are diffused and mixed in the side edge type light guide plate 4. The light is emitted from the emission surface 5 serving as a light emitting unit. The light beam emitted from the exit surface 5 is incident on a transmissive light valve 13 disposed at a physically separated position, and is transmitted through the transmissive light valve 13 to be modulated according to an image signal. The light beam emitted from the transmissive light valve 13 passes through the magnifying optical system including the eyepiece lens 7, passes through the pupil 8, and forms an image on the eye. As the magnifying optical system, in addition to the eyepiece lens 7, a concave mirror optical system or an optical system including a concave mirror and an eyepiece lens may be used. In FIG. 14, ray tracing of the light emitted from the light emitting unit is indicated by a solid line, and tracing of the light ray emitted from the transmissive light valve 13 is indicated by a broken line.
[0067]
Also in this virtual image display device, by arranging the position of the pupil 8 and the light emitting portion at a conjugate position, it is possible to observe an image free from color unevenness and luminance unevenness.
[0068]
【The invention's effect】
As described above, in the virtual image display device according to the present invention, the light emitting unit of the light source is arranged in a positional relationship conjugate with the pupil position of the observer, so that video display without luminance unevenness and color unevenness accompanying the movement of the pupil is performed. Can be observed.
[0069]
And in this virtual image display apparatus, the divergence angle of the emitted light from a light source can be controlled, and an optical system can be reduced in size. Further, by utilizing the direction dependency of the divergence angle of the light emitted from the light source, the pupil movement is adjusted by setting the larger amount of pupil movement, usually the left-right direction as the direction in which the divergence angle of light emitted from the light source is large The possible amount can be increased.
[0070]
In this virtual image display device, the pupil diameter of the optical system can be increased by increasing the shape of the light guide plate in the light source without changing the number or size of the light emitting elements in the light source. The increase in power consumption associated with the increase in the size of the light emitting element and the cost of the light emitting element and the optical element can be suppressed.
[0071]
That is, according to the present invention, unevenness in luminance and intensity due to movement of the pupil occurs when an image displayed by the image display element is observed as a virtual image while maintaining high use efficiency of illumination light for the image display element. It is possible to display a uniform image in terms of luminance and chromaticity, and the range in which the image can be observed, that is, the range in which the pupil can be moved is increased, and the configuration of the illumination optical system is simplified. A virtual image display device can be provided.
[Brief description of the drawings]
FIG. 1 is a side view showing a configuration using a polarizing beam splitter in a virtual image display device according to the present invention.
FIG. 2 is a perspective view showing the shape of a side edge type light guide plate constituting the virtual image display device.
FIG. 3 is a side view showing a light emitting element attached to the side edge type light guide plate.
FIG. 4 is a graph showing the angle dependence of light emitted from a side-edge type light guide plate formed of a light scattering polymer.
FIG. 5 is a plan view showing a coordinate system based on the position of the light emitting element in the side edge type light guide plate.
FIG. 6 is a side view showing the relationship between the emission angle of a light beam emitted from a reflective light valve and the size of a pupil diameter.
FIG. 7 is a plan view showing the relationship between the emission angle of a light beam emitted from a reflective light valve and the size of a pupil diameter.
FIG. 8 is a side view illustrating a definition of a virtual image observable region in the virtual image display device.
FIG. 9 is a side view showing a virtual image observable region in the virtual image display device.
FIG. 10 is a perspective view showing a virtual image observable region in the virtual image display device.
FIG. 11 is a front view showing a relationship between an observation cross section that is a cross section of the virtual image observable region and the size of a human pupil.
FIG. 12 is a front view showing a relationship between an observation cross section that is a cross section of the virtual image observable region and a position of a human pupil.
FIG. 13 is a side view showing the configuration of the virtual image display device according to the present invention using the first to third optical blocks as the optical system for introducing a light beam into the pupil and the magnifying optical system.
FIG. 14 is a side view showing a configuration of a virtual image display device using a transmissive light valve according to the present invention.
FIG. 15 is a side view showing a configuration of a conventional virtual image display device.
FIG. 16 is a side view showing another example of the configuration of a conventional virtual image display device.
[Explanation of symbols]
3 Light-Emitting Element, 4 Side-edge Light Guide Plate, 5 Output Surface, 6 Reflective Light Valve, 7 Eyepiece, 8 Pupil, 10 First Optical Block, 11 Second Optical Block, 12 Third Optical Block, 13 Transmissive light bulb

Claims (10)

A light source having a planar light emitting part, and emitting diffused light from each point of the light emitting part;
A splitter for polarizing light emitted from the light source;
An image display element that modulates and emits light incident through the splitter according to a display image;
A magnifying optical system for condensing the light modulated by the image display element to form a virtual image of the display image,
The light-emitting unit of the light source is a virtual image display device that is arranged in a conjugate region via the magnifying optical system with respect to a region where the virtual image of the display image formed by the magnifying optical system is observable. A light source having a planar light emitting part, and emitting diffused light from each point of the light emitting part;
A splitter for polarizing light emitted from the light source;
An image display element that modulates light incident through the splitter according to a display image and emits the light at a predetermined divergence angle;
A magnifying optical system for condensing the light modulated by the image display element to form a virtual image of the display image,
The light emitting unit of the light source is capable of observing a virtual image of the display image formed by the magnifying optical system, and for a region where light from the entire surface of the image display element is incident on the entire pupil aperture of the observer A virtual image display device disposed in a conjugate region via the magnifying optical system. A light source having a planar light emitting part, and emitting diffused light from each point of the light emitting part;
A splitter for polarizing light emitted from the light source;
An image display element that modulates and emits light incident through the splitter according to a display image;
A magnifying optical system for condensing the light modulated by the image display element to form a virtual image of the display image,
The light emitting unit of the light source is disposed at a conjugate position via the magnifying optical system with respect to a central position of a region where a virtual image of the display image formed by the magnifying optical system can be observed. A virtual image display device. The image display element is an element that modulates light incident from a light source according to a rectangular display image,
The diffused light emitted from the light emitting unit has a wider diffusion angle in a direction corresponding to the long side direction of the display image in the image display element than a diffusion angle in a direction corresponding to the short side direction of the display image. The virtual image display device according to any one of 1 to 3.   The virtual image display device according to claim 1, wherein the image display element is a reflective light valve.   4. The virtual image display device according to claim 1, wherein the light source includes a light emitting diode that emits light of one color or a plurality of colors. 5.   4. The virtual image display device according to claim 1, wherein the light source includes a laser oscillator that emits laser light of one color or a plurality of colors. 5.   4. The virtual image display device according to claim 1, wherein the light source includes a side edge type light guide plate, and a diffusion surface of the side edge type light guide plate serves as a light emitting unit. 5.   9. The virtual image display device according to claim 8, wherein the side edge type light guide plate is formed of a light scattering polymer.   The light-emitting part of the light source is disposed at a position where a conjugate image of the light-emitting part of the light source has a maximum cross-sectional area perpendicular to the optical axis of a region where a virtual image of the display image can be observed. The virtual image display apparatus of any one of these.

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