JP2009151065A - Video display device and head mount display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video display device easily adjusting the position of an optical pupil E while constituting an eye piece optical system 4 compactly. <P>SOLUTION: A luminous flux diameter switching mechanism 30 for switching a luminous flux diameter of light emitted from a light source 11 is disposed such that the following relation holds; ϕView<ϕAli, wherein ϕView denotes the luminous flux diameter of light passing through the optical pupil E in the video observation state and ϕAli denotes the luminous flux diameter of light passing through the optical pupil E in the position adjustment state of the optical pupil E. The luminous flux diameter switching mechanism 30 is constituted of a diaphragm 31, for example. By switching the luminous flux diameter by the use of the diaphragm 31, the relation of ϕView<ϕAli is satisfied and, as the result, an observer easily confirms the position of the optical pupil E in the position adjustment state. An effective optical path region of the eye piece optical system 4 in the position adjustment state is included in an effective optical path region of the eye piece optical system 4 in the video observation state and the relation of ϕView<ϕAli is satisfied without enlarging the eye piece optical system 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image display device that provides an observer with an image displayed on a display element as a virtual image, and a head mounted display (hereinafter also referred to as an HMD) including the image display device.

  An HMD that can be always mounted and observe an image is desired to have good image visibility, a small adjustment portion, and a small size and light weight. Such an HMD can be realized by using an eyepiece optical system (the limit is Maxwell's view) that reduces the light beam diameter of light passing through the optical pupil (exit pupil). That is, by using such an eyepiece optical system, the depth of focus is deepened, so the corresponding diopter is widened, and an image can be observed without adjustment such as diopter correction. In addition, since the light beam diameter of the light passing through the optical pupil is small, the effective optical path area of the eyepiece optical system can be reduced, and the eyepiece optical system and thus the HMD can be reduced in size and weight.

  By the way, when observing an image with the HMD, it is necessary to match the position of the pupil of the observer with the position of the optical pupil of the eyepiece optical system. It is difficult to confirm the target position (for example, the center position of the optical pupil). Therefore, for example, in the HMD disclosed in Patent Document 1, the detection unit detects the positional relationship between the light beam projected on the observer's eyeball and the observer's eyeball, and the moving unit moves the observer according to the detected positional relationship. The light beam projected onto the eyeball is moved. As a result, the observer can observe the image without adjusting the position by himself / herself.

  However, in the configuration of Patent Document 1, the entire system becomes large and heavy by providing the positional relationship detection means and the light flux moving means. Therefore, it cannot be said that such a configuration is suitable for an HMD that is worn for a long time.

  On the other hand, for example, in the HMD of Patent Document 2, only a point light source located at a position conjugate with the pupil position of the observer is selected and lit from among a plurality of illumination point light sources. This eliminates the need for alignment using the mechanical means as described above.

JP 7-311361 A JP-A-8-213325

  However, in the configuration in which a plurality of illumination point light sources are provided as in Patent Document 2, the alignment is easy, but in the eyepiece optical system, the effective light path region necessary for observing the image to the periphery is all point light sources. Must be secured against. For this reason, the eyepiece optical system becomes larger than the configuration in which the point light sources are arranged at only one point on the original axis.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image display device capable of easily adjusting the position of the optical pupil while making the eyepiece optical system compact. Another object of the present invention is to provide an HMD equipped with the video display device.

  An image display apparatus according to the present invention is an image display apparatus including a light source, a display element that displays an image by modulating light from the light source, and an eyepiece optical system that guides image light from the display element to an optical pupil. In the image observation state where the observer observes the image at the position of the optical pupil, the light beam diameter of the light passing through the optical pupil is φView, and the position is adjusted in order to adjust the position of the optical pupil to the observer's pupil position. , Further comprising a beam diameter switching means for switching the beam diameter of the light emitted from the light source so that φView <φAli when the beam diameter of the light passing through the optical pupil is φAli. The effective optical path region of the eyepiece optical system is included in the effective optical path region of the eyepiece optical system in the image observation state.

  According to the above configuration, the light from the light source is modulated by the display element, emitted as image light, and then guided to the optical pupil by the eyepiece optical system. Therefore, the observer can observe the display image (virtual image) of the display element at the position of the optical pupil.

  In addition, since the light beam diameter of the light passing through the optical pupil becomes larger in the position adjustment state than in the image observation state by switching the light beam diameter of the light source light by the light beam diameter switching means, in the position adjustment state, the observer The position of the optical pupil can be easily confirmed, and the optical pupil position can be easily adjusted.

  Further, since the effective optical path region in the position adjustment state in the eyepiece optical system is included in the effective optical path region in the image observation state, it passes through the optical pupil in the position adjustment state without configuring the eyepiece optical system large. The light beam diameter can be increased. Therefore, it is possible to realize an image display device in which the position of the optical pupil can be easily adjusted while the eyepiece optical system is made compact.

  In the video display device of the present invention, in the position adjustment state, it is desirable that the illuminance within the pupil plane of the light passing through the optical pupil is maximum at the center position. In this case, the observer can easily recognize the center of the optical pupil at the time of position adjustment, and the position adjustment can be performed accurately.

  In the video display device of the present invention, it is desirable that the peripheral illuminance within the pupil plane of the light passing through the optical pupil is ½ or less of the central illuminance in the position adjustment state. In this case, in the position adjustment state, the difference between the central illuminance in the plane of the optical pupil and the peripheral illuminance becomes large, so that it becomes easier for the observer to recognize the center of the optical pupil during position adjustment. Can be performed more accurately.

  In the video display device of the present invention, in the position adjustment state, it is desirable that the illuminance within the pupil plane of the light passing through the optical pupil decreases stepwise from the center toward the periphery. In this case, position adjustment in the direction from the periphery toward the center in the plane of the optical pupil is facilitated.

  In the video display device of the present invention, it is desirable that the beam diameter switching means switches the beam diameter of the light emitted from the light source so that 3φView ≦ φAli. By switching the light beam diameter of the light source light by such a light beam diameter switching means, the light beam diameter of the light passing through the optical pupil in the position adjustment state is at least three times the light beam diameter of the light passing through the optical pupil in the image observation state. Therefore, at the start of position adjustment, the observer can easily find the optical pupil.

  In the video display device of the present invention, it is desirable that the video display area of the display element is smaller in the position adjustment state than in the video observation state.

  When the eyepiece optical system is designed so that the aberration generated in the image observation state is corrected, the image display area of the display element remains the same area (all pixels ON) in the image observation state and the position adjustment state. When the light beam diameter of the light passing through the optical pupil is increased in the position adjustment state, aberrations are generated toward the periphery of the image and the image is blurred. Therefore, it is difficult for the observer to recognize the exact center position of the optical pupil.

  On the other hand, by making the image display area of the display element smaller in the position adjustment state than in the image observation state (for example, by turning on only the pixel at the center), the portion where the image appears clearly (the center of the image) Can be used for position adjustment of the optical pupil, and the observer can more easily recognize the exact center position of the optical pupil.

  In the image display device of the present invention, it is desirable that the light beam diameter switching means is disposed at a position substantially conjugate with the optical pupil. In this case, the switching of the beam diameter of the light passing through the optical pupil can be performed accurately and reliably by switching the beam diameter of the light source light by the beam diameter switching means.

  In the image display device of the present invention, the light beam diameter switching means may be configured to have a diaphragm for switching the area of the opening between the image observation state and the position adjustment state. For example, when the light emission area of the light source is large with respect to the light beam diameter of the light passing through the optical pupil in the image observation state, the light beam diameter of the light source light is changed by switching the area of the opening through which the light source light passes by the diaphragm. It is possible to easily switch between the image observation state and the position adjustment state.

  In the video display device of the present invention, the light beam diameter switching means further includes an illuminance adjustment filter for adjusting the illuminance in the pupil plane of the light emitted from the light source, and the illuminance adjustment filter has a central portion. It is desirable to reduce the transmittance of light transmitted through the peripheral portion rather than the transmittance of transmitted light.

  In this configuration, the illumination intensity within the pupil plane of the light passing through the optical pupil can be decreased from the center toward the periphery in the position adjustment state by switching the area of the opening by the diaphragm. Thereby, the observer can easily adjust the position in the direction from the periphery to the center in the plane of the optical pupil.

  In the video display device of the present invention, it is desirable that the illuminance adjustment filter lowers the transmittance of light transmitted through the peripheral portion in at least two stages. In this case, in the position adjustment state, the illuminance within the pupil plane of the light passing through the optical pupil can be reduced in at least two steps from the center toward the periphery. This makes it easier for the observer to adjust the position in the direction from the periphery to the center in the plane of the optical pupil.

  In the image display device of the present invention, the light beam diameter switching means includes a diffusion plate for diffusing light from the light source and a diffusion plate in the optical path in the position adjustment state, while the diffusion plate is disposed in the image observation state. The structure which has the drive part removed from an optical path may be sufficient.

  For example, when the light emission area of the light source is small with respect to the light beam diameter of the light passing through the optical pupil in the image observation state, the light emission area of the light source can be artificially increased by the diffusion plate, and the diffusion plate by the drive unit The light beam diameter of the light emitted from the light source can be easily switched between the image observation state and the position adjustment state.

  In the video display device of the present invention, the light beam diameter switching means may switch the light beam diameter of the light emitted from the light source in at least two stages in the position adjustment state. In the position adjustment state, the observer can easily adjust the center of his / her pupil to the center of the optical pupil by changing the beam diameter of the light source light stepwise and performing the position adjustment stepwise.

  In the image display device of the present invention, the eyepiece optical system includes a volume phase type reflection type hologram optical element, and the hologram optical element guides the image light from the display element to the optical pupil by diffracting and reflecting the image light. Alternatively, the configuration may be such that external light is transmitted and guided to the optical pupil.

  The volume phase type reflection hologram optical element has a narrow reflection wavelength range and a high external light transmittance. Therefore, in the video observation state, the observer can observe the external image with see-through while observing the display video (virtual image).

  The HMD of the present invention includes the above-described video display device of the present invention and support means for supporting the video display device in front of an observer's eyes. In this configuration, since the video display device is supported by the support means, the observer can observe the video provided from the video display device stably in a hands-free manner for a long time.

  In the HMD of the present invention, the support means fixes the relative position of the eyepiece optical system with respect to the observer's head after adjusting the position of the optical pupil of the eyepiece optical system to the position of the observer's pupil. It is desirable to have a means. In this configuration, the fixing means fixes the relative position of the eyepiece optical system with respect to the observer's head after adjusting the position of the optical pupil, so that the observer can reliably obtain a good image at the position of the optical pupil. Can be observed.

  According to the present invention, since the light beam diameter of the light passing through the optical pupil becomes larger in the position adjustment state than in the image observation state by switching the light beam diameter of the light source light by the light beam diameter switching means, Makes it easier to confirm the position of the optical pupil, and the position of the optical pupil can be easily adjusted. Further, since the effective optical path region in the position adjustment state in the eyepiece optical system is included in the effective optical path region in the image observation state, it passes through the optical pupil in the position adjustment state without configuring the eyepiece optical system large. The light beam diameter can be increased. Therefore, it is possible to realize an image display device in which the position of the optical pupil can be easily adjusted while the eyepiece optical system is made compact.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to the drawings.

(1. Configuration of HMD)
FIG. 2 is a perspective view showing a schematic configuration of the HMD according to the present embodiment. The HMD includes a video display device 1 and support means 2.

  The video display device 1 allows an observer to observe an outside world image with see-through, displays an image, and provides it to the observer as a virtual image. The video display device 1 is configured by integrating an eyepiece optical system 4 with a housing 3 that houses a light source 11 and a display element 13 (both see FIGS. 1A and 1B) to be described later. A signal for controlling the light source 11 and the display element 13 and driving power of each part are supplied to each part via a cable 5 that penetrates the housing 3. The eyepiece optical system 4 has a shape like one lens of a pair of glasses (lens for right eye in FIG. 2) as a whole. The lens 6 corresponding to the left eye lens of the spectacles is a dummy lens.

  The support means 2 is a support member that supports the video display device 1 in front of the observer's eyes. In the present embodiment, the support means 2 supports one video display device 1 corresponding to the right eye of the observer, but two video display devices 1 corresponding to the eyes of the viewer. You may support. The support means 2 includes a member corresponding to a frame and a temple of spectacles and a fixing mechanism 7.

  The fixing mechanism 7 adjusts the position of the optical pupil (exit pupil) of the eyepiece optical system 4 to the position of the observer's pupil (pupil, iris), and then adjusts the position of the eyepiece optical system 4 to the viewer's head. It is a fixing means for fixing the relative position, and is configured to include a right nose pad 7R and a left nose pad 7L that can move in contact with the nose of the observer, and a lock portion that locks them. Since the support means 2 has the fixing mechanism 7, after adjusting the position of the optical pupil E, the observer can reliably and stably observe a good image at the position of the optical pupil E. . Details of the position adjustment will be described later.

(2. About video display device)
Next, details of the above-described video display device 1 will be described. For convenience of explanation below, a state in which an observer observes an image with his / her pupil P aligned with the position of the optical pupil E is referred to as an image observation state, and the position of the optical pupil E and the observer's A state in which the position adjustment for matching the position of the pupil P is referred to as a position adjustment state.

  FIG. 1A is a cross-sectional view showing the configuration of the video display device 1 according to the present embodiment in the position adjustment state, and FIG. 1B is a cross-sectional view showing the configuration of the video display device 1 in the video observation state. FIG. Thus, the video display device 1 includes the light source 11, the illumination optical system 12, the display element 13, the eyepiece optical system 4, and the light beam diameter switching mechanism 30 (light beam diameter switching means).

  For convenience of explanation, directions are defined as follows. First, an axis that optically connects the center of the display area of the display element 13 and the center of the optical pupil E formed by the eyepiece optical system 4 is an optical axis. The optical axis direction when the optical path from the light source 11 to the optical pupil E is developed is taken as the Z direction. In addition, a direction perpendicular to an optical axis incident surface of a hologram optical element 23 (to be described later) of the eyepiece optical system 4 is defined as an X direction, and a direction perpendicular to the ZX plane is defined as a Y direction. The optical axis incident surface of the hologram optical element 23 refers to a plane including the optical axis of incident light and the optical axis of reflected light in the hologram optical element 23, that is, the YZ plane. In addition, the positive / negative of each direction of X, Y, and Z shall not be ask | required.

  The light source 11 is composed of, for example, an RGB integrated LED that emits light having wavelengths corresponding to the three primary colors of RGB. The light source 11 may be composed of a white LED having a wide emission wavelength.

  The illumination optical system 12 guides the light emitted from the light source 11 to the display element 13, and includes, for example, a cylindrical concave mirror that reflects incident light and collects light only on the YZ plane. The illumination optical system 12 may be composed of a flat reflection mirror and a condensing lens, or may be composed of only a condensing lens.

  The display element 13 modulates light incident from the light source 11 via the illumination optical system 12 in accordance with image data and displays an image, and is composed of, for example, a transmissive LCD having a plurality of pixels in a matrix. Has been. The display element 13 is arranged such that the long side direction of the rectangular display screen is the X direction and the short side direction is the Y direction. Note that the display element 13 may be formed of a reflective light modulation element.

  The eyepiece optical system 4 is an optical system that guides the image light from the display element 13 to the optical pupil E and guides the light of the external image (external light) to the optical pupil E. The eyepiece prism 21, the deflection prism 22, And a holographic optical element 23.

  The eyepiece prism 21 totally reflects image light from the display element 13 and guides it to the hologram optical element 23. The eyepiece prism 21 is made of, for example, an acrylic resin together with the deflection prism 22. The eyepiece prism 21 has a shape in which the lower end portion of the parallel plate is wedge-shaped. The upper end surface of the eyepiece prism 21 is a surface 21a as an incident surface for image light, and the two surfaces positioned in the front-rear direction are surfaces 21b and 21c parallel to each other.

  The deflecting prism 22 is configured by a substantially U-shaped parallel plate in plan view (see FIG. 2), and when the deflecting prism 22 is bonded to the lower end portion and both side surface portions (left and right end surfaces) of the eyepiece prism 21, the eyepiece prism. 21 is a substantially parallel flat plate. The deflection prism 22 is provided by being bonded to the eyepiece prism 21 so as to sandwich the hologram optical element 23 therebetween. Thereby, the refraction when the external light is transmitted through the wedge-shaped lower end portion of the eyepiece prism 21 can be canceled by the deflecting prism 22, and it is possible to prevent the external image observed through the see-through from being distorted.

  The hologram optical element 23 is a volume phase type reflection hologram optical element that diffracts and reflects the image light from the display element 13 and guides it to the optical pupil E, and at the same time transmits external light to the optical pupil E. The prism 21 is provided on the joint surface with the deflecting prism 22. The volume phase type reflection hologram optical element has a narrow reflection wavelength range and high external light transmittance. By using this as the hologram optical element 23, the observer can observe the display image (virtual image). It becomes possible to observe the outside world image with see-through. Further, the hologram optical element 23 has an axially asymmetric positive optical power, and has the same function as an aspherical concave mirror having a positive optical power. Thereby, the degree of freedom of arrangement of each optical member constituting the apparatus can be increased, and the apparatus can be easily reduced in size, and an image with good aberration correction can be provided to the observer.

  The beam diameter switching mechanism 30 switches the beam diameter of the light emitted from the light source 11 between the position adjustment state and the image observation state, thereby changing the light beam diameter of the light passing through the optical pupil E between the position adjustment state and the image observation state. The details will be described later.

  Next, the operation of the video display device 1 having the above configuration will be described. The operation described below is basically the same in the position adjustment state of FIG. 1A and the image observation state of FIG. However, the image displayed on the display element 13 is, for example, a white pattern (all pixels ON) image in the position adjustment state, and a normal color image (an image to be observed by the observer) in the image observation state.

  The light emitted from the light source 11 enters the display element 13 via the light beam diameter switching mechanism 30 and the illumination optical system 12, and is modulated there and emitted as image light. The image light from the display element 13 enters the inside of the eyepiece prism 21 of the eyepiece optical system 4 from the surface 21a, is totally reflected a plurality of times by the two surfaces 21b and 21c facing each other, and enters the hologram optical element 23. . The light incident on the hologram optical element 23 is diffracted and reflected there and reaches the optical pupil E. Therefore, at the position of the optical pupil E, the observer can observe an enlarged virtual image of the image displayed on the display element 13.

  On the other hand, the eyepiece prism 21, the deflecting prism 22, and the hologram optical element 23 transmit almost all of the external light, so that the observer can observe the external image. Therefore, the virtual image of the image displayed on the display element 13 is observed while overlapping a part of the external image.

(3. Adjustment of optical pupil position)
Next, the position adjustment of the optical pupil E will be described. In the position adjustment state, the beam diameter of light emitted from the light source 11 is switched by the beam diameter switching mechanism 30 described above. In the present embodiment, as shown in FIGS. 1A and 1B, the beam diameter switching mechanism 30 includes a diaphragm 31 having an opening. That is, the diaphragm 31 switches the area of the opening through which the light emitted from the light source passes between the position adjustment state and the image observation state, thereby changing the beam diameter of the light passing through the optical pupil E between the position adjustment state and the image observation. Switch between states. The diaphragm 31 is disposed at a position substantially conjugate with the optical pupil E, and the light beam diameter of the light passing through the optical pupil E can be accurately and reliably switched between the position adjustment state and the image observation state. Yes.

  Here, if the light beam diameter of the light passing through the optical pupil E in the image observation state is φView and the light beam diameter of the light passing through the optical pupil E in the position adjustment state is φAli, in this embodiment, φView <φAli. As described above, the diameter of the light emitted from the light source 11 is switched by the diaphragm 31. That is, as shown in FIGS. 1A and 1B, the area of the opening of the diaphragm 31 in the position adjustment state is larger than the area of the opening in the image observation state, thereby passing through the optical pupil E. The diameter of the light beam to be emitted is larger in the position adjustment state than in the image observation state.

  Incidentally, in this embodiment, the light beam diameters φView and φAli of the light passing through the optical pupil E are as shown in Table 1. Table 1 also shows the angle of view θView at the position of the optical pupil E in the image observation state and the angle of view θAli at the position of the optical pupil E in the position adjustment state.

  As described above, since the light beam diameter of the light passing through the optical pupil E becomes larger in the position adjustment state than in the image observation state by switching the light beam diameter of the light source light by the diaphragm 31, in the position adjustment state, the observer It becomes easy to recognize and confirm the position of the optical pupil E based on the light having a large diameter, and the position of the optical pupil E can be easily adjusted. That is, the observer can easily find the position of the optical pupil E in the position adjustment state, and easily align the optical pupil E with his / her pupil P.

  In particular, in this embodiment, from Table 1, the diaphragm 31 switches the beam diameter of the light emitted from the light source 11 so that 3φView = φAli. By such switching of the beam diameter, the beam diameter of the light passing through the optical pupil E is sufficiently large in the position adjustment state, so that the observer can find the optical pupil E more easily at the start of position adjustment. Thus, the optical pupil E and the own pupil P can be more easily matched. This effect can be reliably obtained if φAli is larger than three times φView. That is, the above effect can be obtained by switching the beam diameter of the light emitted from the light source 11 so that the diaphragm 31 satisfies 3φView ≦ φAli.

  In the present embodiment, the light beam diameter switching mechanism 30 includes the diaphragm 31 that switches the area of the opening between the image observation state and the position adjustment state, so that the light beam diameter of the light emitted from the light source 11 is It is possible to easily switch between the image observation state and the position adjustment state, whereby the light beam diameter of the light passing through the optical pupil E can be easily switched between the image observation state and the position adjustment state. The configuration using the diaphragm 31 as the light beam diameter switching mechanism 30 is particularly effective when the light emitting area of the light source 11 is large with respect to the light beam diameter φView of the light passing through the optical pupil E in the image observation state.

  By the way, in this embodiment, the video display area of the display element 13 is smaller in the position adjustment state than in the video observation state. That is, in the YZ plane of FIGS. 1A and 1B, when the video display area of the display element 13 in the position adjustment state is R1, and the video display area of the display element 13 in the video observation state is R2, R1 <R2. Note that such switching of the video display area is performed, for example, by turning on all the pixels of the display element 13 (light transmission state) in the video observation state and turning off the peripheral pixels of the display element 13 in the position adjustment state ( This can be realized by setting the pixel on the inner side (optical axis side) from the peripheral portion to ON (light transmission state).

  The eyepiece optical system 4 is designed to correct aberrations that occur in the image observation state (the diameter of the light beam passing through the optical pupil E is small). When such an eyepiece optical system 4 is used, When the light beam diameter of the light passing through the optical pupil E in the position adjustment state is increased in the state of R1 = R2, aberration is generated toward the peripheral portion of the image, and the imaging performance is deteriorated (the image is blurred). In the position adjustment state, it is only necessary to confirm the position of the optical pupil E. Therefore, degradation of the imaging performance is not particularly problematic. However, by setting R1 <R2 as in this embodiment, the image is clearly displayed. Only the portion (the central portion of the image) can be used for the position adjustment of the optical pupil E. In this case, the observer can more easily recognize the accurate center position of the optical pupil E, and the position adjustment of the optical pupil E is further facilitated.

  Further, by switching the video display area as described above, the effective optical path area of the eyepiece optical system 4 in the position adjustment state is included in the effective optical path area of the eyepiece optical system 4 in the video observation state. Note that the above-described effective optical path region refers to a region (range) through which light that creates an image that can be clearly observed passes in the eyepiece optical system 4. More simply, the effective optical path region of the eyepiece optical system 4 in the position adjustment state and the image observation state is shown in FIGS. 3A and 3B showing optical path diagrams in the image display device 1 of the second embodiment to be described later. , T1 and T2, respectively.

  In general, when the light beam diameter of the light passing through the optical pupil E is increased, the eyepiece optical system 4 must be configured larger in order to ensure an effective optical path region of the eyepiece optical system 4. However, in the present embodiment, as described above, the effective optical path region of the eyepiece optical system 4 in the position adjustment state is included in the effective optical path region of the eyepiece optical system 4 in the image observation state. ΦView <φAli can be realized without a large configuration. Therefore, it is possible to realize the video display device 1 in which the position of the optical pupil E can be easily adjusted while the eyepiece optical system 4 is configured compactly. In addition, since the compact eyepiece optical system 4 can be used, it is possible to realize an HMD that is small and light, has high image quality, and can be used for a long time.

  In the present embodiment, since the light beam diameter of the light passing through the optical pupil E is smaller in the image observation state than in the position adjustment state, the depth of focus in the image observation state is deep, and the corresponding diopter is widened. That is, in an image observation state, an image can be observed without performing diopter correction unless extreme myopia or hyperopia. On the other hand, since the depth of focus in the position adjustment state is shallow, in the position adjustment state, not only the in-plane direction of the optical pupil E but also the position adjustment in the optical axis direction can be performed. That is, if the optical pupil E is displaced in the optical axis direction, the image is easily blurred. Therefore, it is possible to adjust the position of the optical pupil E in the optical axis direction using this.

  In the above, switching of the video display area of the display element 13 and setting of the effective optical path area of the eyepiece optical system 4 have been described in the vertical direction (in the YZ plane), but the same applies to the horizontal direction (in the XY plane). Can think.

  In this embodiment, θView is ± 5.0 °, and the angle of view is such that the observer's eyes do not rotate significantly. Even in the case of ± 8 ° or more, for example, the configuration of the present embodiment described above is effective. The same can be said for the following embodiments.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to the drawings. For convenience of explanation below, the same components as those in the first embodiment are denoted by the same member numbers, and description thereof is omitted.

  3 (a) and 3 (b) are explanatory views showing the optical path of the video display device 1 according to the present embodiment in an expanded manner. In particular, FIG. 3 (a) is an explanatory view in the position adjustment state, and FIG. (B) is explanatory drawing in a video observation state. The video display device 1 of the present embodiment is different from the first embodiment in that the light source 11 is configured by an LED having a condensing lens at the tip, and the illumination optical system 12 is configured by a condensing lens. ing. FIG. 4 shows the light emission characteristics of the light source 11. However, the light emission luminance on the vertical axis in FIG. 4 indicates a relative value with respect to the maximum luminance (luminance at the optical axis position).

  In this embodiment, the light beam diameter switching mechanism 30 further includes an illuminance adjustment filter 32 in addition to the diaphragm 31. The illuminance adjustment filter 32 is a filter for adjusting the illuminance (illumination luminance) in the pupil plane of the light emitted from the light source 11, and is disposed closer to the light source 11 than the stop 31. The illuminance adjustment filter 32 includes a central portion 32a and a peripheral portion 32b. The central portion 32a is made of, for example, a hole, and the peripheral portion 32b is made of, for example, a semipermeable membrane.

  FIG. 5 is an explanatory diagram showing the transmission characteristics of the illuminance adjustment filter 32. Note that the transmittance on the vertical axis in FIG. 5 indicates a relative value with respect to the maximum transmittance (transmittance at the optical axis position). Since the illuminance adjustment filter 32 includes the central portion 32a and the peripheral portion 32b, the central portion 32a has a high light transmittance (for example, 100% transmittance), and the peripheral portion 32b has a low light transmittance. (For example, transmittance 50%). Therefore, in the illuminance adjustment filter 32, the transmittance of light transmitted through the peripheral portion 32b is reduced to, for example, ½ of the transmittance of light transmitted through the central portion 32a.

  Also in the present embodiment, the diameter of the light emitted from the light source 11 is switched by the diaphragm 31 so that φView <φAli. That is, as shown in FIGS. 3A and 3B, the area of the opening of the diaphragm 31 in the position adjustment state is larger than the area of the opening in the image observation state and the center of the illuminance adjustment filter 32. It is wider than the area of the part 32a. Thereby, the beam diameter of the light passing through the optical pupil E is larger in the position adjustment state than in the image observation state.

  Incidentally, in this embodiment, φView and φAli are as shown in Table 2. Table 2 also shows θView and θAli.

  As described above, in the present embodiment as well, in the same way as in the first embodiment, the light beam diameter of the light passing through the optical pupil E is more adjusted than the image observation state by switching the light beam diameter of the light source light by the diaphragm 31. growing. Thereby, in the position adjustment state, the observer can easily find the position of the optical pupil E, that is, the place where the light enters in his / her pupil P first, and can easily adjust the position of the optical pupil E. Can do.

  FIG. 6 is an explanatory diagram showing illumination characteristics of the optical pupil E on the pupil plane. Note that the illuminance on the vertical axis in FIG. 6 represents a relative value with respect to the maximum illuminance (illuminance at the optical axis position). When the light source 11 having the characteristics shown in FIG. 4 is used and the light from the light source 11 is guided to the optical pupil E via the illuminance adjustment filter 32 having the characteristics shown in FIG. In the state, the illuminance is high in the central part of the optical pupil E, and the illuminance is low in the peripheral part. In particular, in the position adjustment state, the peripheral illuminance within the pupil plane of light passing through the optical pupil E is ½ or less of the central illuminance.

  As described above, the light beam diameter switching mechanism 30 includes the diaphragm 31 and the illuminance adjustment filter 32, so that the illuminance in the pupil plane of the light passing through the optical pupil E is centered in the position adjustment state. It can be lowered from to the periphery. Thereby, the observer can easily adjust the position in the direction from the periphery to the center in the plane of the optical pupil E.

  That is, in the position adjustment state, the observer brings the video display device 1 close to the eyes, first searches for a place where the light enters the pupil P, and when the light enters the pupil P, the viewer moves the video display device 1 around it. After moving the image display apparatus 1 to a position where the illumination light enters the pupil P in a well-balanced and brightest manner, the position may be fixed by the fixing mechanism 7 (see FIG. 2).

  Further, in the position adjustment state, the illuminance within the pupil plane of the light passing through the optical pupil E is maximum at the center position, so that the observer can easily recognize the center of the optical pupil E during position adjustment. The position can be adjusted accurately.

  In particular, in this embodiment, in the position adjustment state, the peripheral illuminance in the pupil plane of the light passing through the optical pupil E is ½ or less of the central illuminance, and the difference between the central illuminance and the peripheral illuminance is large. The observer can more easily recognize the center of the optical pupil E at the time of position adjustment, and can perform position adjustment more accurately.

  In the present embodiment, by using the illuminance adjustment filter 32, in the position adjustment state, the illuminance within the pupil plane of the light passing through the optical pupil E gradually decreases from the center toward the periphery. Therefore, the observer can surely recognize the center of the optical pupil E, and the position adjustment in the direction from the periphery to the center in the plane of the optical pupil E is further facilitated.

  Also in the present embodiment, as in the first embodiment, the video display area of the display element 13 is smaller in the position adjustment state than in the video observation state, and as a result, as shown in FIGS. In addition, the effective optical path region T1 of the eyepiece optical system 4 in the position adjustment state is included in the effective optical path region T2 of the eyepiece optical system 4 in the image observation state (T1 <T2). Therefore, similarly to the first embodiment, φView <φAli can be realized without making the eyepiece optical system 4 large, and the video display device 1 in which the position of the optical pupil E can be easily adjusted can be realized.

  In the position adjustment state, since the area of the aperture of the diaphragm 31 is large and φAli is large, the illuminance can be recognized in the range of B in FIG. On the other hand, in the image observation state, since the area of the opening of the diaphragm 31 is small and φView is small, the illuminance is recognized in the range of A that is narrower than B in FIG. At this time, since the illuminance is generally high in the range A, the observer can observe a bright image in the image observation state.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to the drawings. For convenience of explanation below, the same components as those in the first and second embodiments are denoted by the same member numbers, and the description thereof is omitted.

  7 (a) and 7 (b) are explanatory views showing the optical path of the video display device 1 according to the present embodiment in an expanded manner. In particular, FIG. 7 (a) is an explanatory view in the position adjustment state. (B) is explanatory drawing in a video observation state. The video display device 1 according to the present embodiment is different from the first and second embodiments in that the light source 11 is configured by a surface-mount type LED having a small light emitting area. Incidentally, the size of the light emitting portion of the light source 11 is, for example, 0.6 mm × 0.6 mm.

  In the present embodiment, the light beam diameter switching mechanism 30 is configured to include a diffusion plate 33 and a drive unit 34 instead of the diaphragm 31 and the illuminance adjustment filter 32. The diffusion plate 33 diffuses light from the light source 11 and is disposed at a position substantially conjugate with the optical pupil E. As shown in FIG. 7A, the drive unit 34 arranges the diffusion plate 33 in the optical path when in the position adjustment state. On the other hand, when in the image observation state, the driving unit 34 as shown in FIG. 33 is removed from the optical path. For example, the motor 33 has a rotation axis parallel to the optical axis and is configured by a motor that rotates the diffusion plate 33. In the present embodiment, the size of the video display area in the display element 13 is the same in the position adjustment state and the video observation state.

  In the image observation state, the light beam diameter of the light passing through the optical pupil E can be reduced to the chip surface size of the light source 11 by retracting the diffusion plate 33 out of the optical path by the drive unit 34. As a result, the depth of focus becomes deeper, and in the image observation state, it is possible to observe the image without performing diopter correction.

  On the other hand, in the position adjustment state, the diffusing plate 33 is arranged in the optical path by the drive unit 34, so that the light emission area of the light source 11 can be easily increased in a pseudo manner. Therefore, even when the light emission area of the light source 11 is small with respect to φView, the light beam diameter of the light source light can be easily switched between the image observation state and the position adjustment state by putting the diffusion plate 33 in and out of the optical path, and φView < φAli can be realized easily.

  Incidentally, in this embodiment, φView and φAli are as shown in Table 3. Table 3 also shows θView and θAli.

  As described above, also in this embodiment, the light beam diameter switching mechanism 30 causes the light beam diameter of the light passing through the optical pupil E to be larger in the position adjustment state than in the image observation state. The position of the pupil E can be easily adjusted.

  In this embodiment, from Table 3, θView and θAli are the same in the position adjustment state and the video observation state, and the video display area of the display element 13 is also the same in the position adjustment state and the video observation state. Therefore, out of the image light incident on the eyepiece optical system 4, the image light emitted from the peripheral portion of the display element 13 is imaged at the end of the eyepiece optical system 4 and emitted from the center portion of the display element 13. Only light enters the optical pupil E via the eyepiece optical system 4. Therefore, at the position of the optical pupil E, the peripheral part is dark and the central part is bright. Note that the effective optical path region of the eyepiece optical system 4 indicates a region through which light that makes a clearly observable image passes. Therefore, the effective optical path region in the present embodiment can be said to be the same in the position adjustment state and the image observation state. (T1 = T2). In addition, as the optical pupil E shifts in the optical axis direction, that is, as the position of the optical pupil E in the optical axis direction and the position of the observer's pupil P shift, the peripheral portion of the display image of the display element 13 is lost. The range of the image that can be seen in the position adjustment state becomes small (only the vicinity of the center of the display image can be seen).

  Therefore, in this embodiment, in the position adjustment state, when the observer finds the position of the light beam, first, the observer adjusts the optical pupil E so that his / her pupil P is positioned at the center (on the optical axis), and then The distance from the video display device 1 may be adjusted on the optical axis. Then, the position of the video display device 1 may be fixed when the video is the largest and brightest (when the pupil P is positioned on the pupil plane of the optical pupil E). By such a method, the three-dimensional position adjustment of the optical pupil E can be easily performed.

  In the position adjustment state, the image displayed on the display element 13 may be a white pattern (all pixel white display), or may be a check pattern (checkered pattern), for example. Especially in the latter case, in the position adjustment state, it is easy to determine whether most of the displayed image is visible or only the vicinity of the center is visible, and it is easy to determine the positional deviation in the optical axis direction. It can be said that it is preferable in that respect.

  In the present embodiment, the light beam diameter of the light source light is switched between the image observation state and the position adjustment state by using one type of diffusion plate 33. However, the optical pupil is different in each of the image observation state and the position adjustment state. A configuration may be adopted in which two diffuser plates having a size corresponding to the light beam diameter of the light passing through E are provided, and the light beam diameter is switched by taking them in and out. That is, the light beam diameter switching means includes a first diffusion plate having a size corresponding to the light beam diameter of light passing through the optical pupil in the image observation state, and a size corresponding to the light beam diameter of light passing through the optical pupil in the position adjustment state. The second diffuser plate and a drive unit that arranges the first diffuser plate in the optical path in the image observation state and arranges the second diffuser plate in the optical path in the position adjustment state. It is good.

[Embodiment 4]
The following will describe still another embodiment of the present invention with reference to the drawings. For convenience of explanation below, the same members as those in the first to third embodiments are denoted by the same member numbers, and the description thereof is omitted.

  FIGS. 8A, 8B, and 8C are explanatory views showing the optical path of the video display device 1 according to the present embodiment in an expanded manner. In particular, FIG. 8A is an explanation in the first position adjustment state. FIG. 8B is an explanatory diagram in the second position adjustment state, and FIG. 8C is an explanatory diagram in the video observation state. In the present embodiment, the beam diameter switching mechanism 30 of the video display device 1 is configured to include all of the diaphragm 31, the illuminance adjustment filter 32, the diffusion plate 33, and the drive unit 34 described in the first to third embodiments. . However, the configuration of the illuminance adjustment filter 32 is slightly different from that of the second embodiment. The diffusion plate 33, the illuminance adjustment filter 32, and the diaphragm 31 are arranged in this order from the light source 11 side. For convenience, the drive unit 34 is not shown in FIGS. 8A, 8B, and 8C, and the diffusion plate 33 is not shown in FIG. 8C.

  FIG. 9 shows the light emission characteristics when the light source 11 and the diffusion plate 33 are regarded as one light source. Note that the light emission luminance on the vertical axis in FIG. 9 indicates a relative value with respect to the maximum luminance (luminance at the optical axis position). As shown in the figure, since the light from the light source 11 is diffused by the diffusion plate 33, the light emission luminance is distributed over a relatively wide range in a direction perpendicular to the optical axis.

The illuminance adjustment filter 32 shown in FIGS. 8A, 8B, and 8C includes a central portion 32a and a peripheral portion 32b. The peripheral portion 32b further includes the first peripheral portion 32b ₁ and the second peripheral portion 32b. It is composed of the peripheral portion 32 b _2. The central portion 32a is made of, for example, a hole, and the peripheral portion 32b is made of, for example, a semipermeable membrane.

In the peripheral portion 32b, the second peripheral portion 32b ₂ is formed outside the first peripheral portion 32b ₁ , and the transmittance is set lower than that of the first peripheral portion 32b ₁ . With such a configuration of the illuminance adjustment filter 32, the illuminance of the light transmitted through the peripheral portion 32b decreases in two steps with reference to the illuminance of the light transmitted through the central portion 32a.

Here, FIG. 10 is an explanatory diagram showing the transmission characteristics of the illuminance adjustment filter 32 of the present embodiment. Note that the transmittance on the vertical axis in FIG. 10 represents a relative value with respect to the maximum transmittance (transmittance at the optical axis position). Since the illuminance adjustment filter 32 is configured by the central portion 32a and the peripheral portion 32b (first peripheral portion 32b ₁ + second peripheral portion 32b ₂ ), the central portion 32a has a high light transmittance (for example, transmission). 100%), the second peripheral portion 32b ₂ has a low light transmittance (for example, 30% transmittance), and the first peripheral portion 32b ₁ has a transmittance therebetween (for example, a transmittance of 60%). . Thus, in the illuminance adjustment filter 32, the transmittance decreases stepwise from the center toward the periphery.

  In the present embodiment, the beam diameter switching mechanism 30 switches the beam diameter of the light emitted from the light source 11 in a total of three stages in the position adjustment state and the image observation state.

More specifically, in a first position adjustment state, as shown in FIG. 8 (a), the center portion 32a of the illuminance adjustment filter light from the light source 11, a first peripheral portion 32b ₁ and the second peripheral portion 32b The diameter (area) of the opening is adjusted by the diaphragm 31 so that all of ₂ are transmitted to the optical pupil E.

Subsequently, in the second position adjustment state, as shown in FIG. 8B, the light from the light source 11 passes only through the central portion 32a and the first peripheral portion 32b _{1 of the} illuminance adjustment filter and enters the optical pupil E. In order to be guided, the diameter of the opening is made smaller by the diaphragm 31 than in the first position adjustment state.

  On the other hand, in the image observation state, as shown in FIG. 8C, the aperture 31 is opened by the diaphragm 31 so that the light from the light source 11 passes only through the central portion 32a of the illuminance adjustment filter and is guided to the optical pupil E. The diameter is made smaller than that in the second position adjustment state.

  Note that the diffusing plate 33 is disposed in the optical path by the drive unit 34 in the first and second position adjustment states, and the diffusing plate 33 is retracted from the optical path in the image observation state.

  As described above, φView <φAli is also realized in this embodiment by switching the beam diameter of the light emitted from the light source 11 as shown in FIGS. 8A, 8B, and 8C by the diaphragm 31. Can do. In particular, if the light beam diameter of light passing through the optical pupil E in the first position adjustment state is φAli-1, and the light beam diameter of light passing through the optical pupil E in the second position adjustment state is φAli-2, then φView <ΦAli-2 <φAli-1 can be realized.

  Incidentally, in this embodiment, φView, φAli-1 and φAli-2 are as shown in Table 4. The angle of view θView at the position of the optical pupil E in the image observation state and the angles of view θAli-1 and θAli-2 at the position of the optical pupil E in the first and second position adjustment states are also shown. 4 shows.

  As described above, also in the present embodiment, the light beam diameter of the light passing through the optical pupil E becomes larger in the position adjustment state than in the image observation state by switching the light beam diameter of the light source light by the diaphragm 31. The observer can easily adjust the position of the optical pupil E.

  Further, in the position adjustment state, the light beam diameter switching mechanism 30 switches the light beam diameter of the light source light in two steps to reduce it stepwise, so that the light beam diameter of the light passing through the optical pupil E is stepwise as described above. The position can be adjusted stepwise by making it smaller. Thereby, the observer can adjust the center of the optical pupil E and the center of his / her pupil P in a stepwise manner, so that the centers can be easily aligned with each other.

  FIG. 11 is an explanatory diagram showing illumination characteristics of the optical pupil E on the pupil plane. Note that the illuminance on the vertical axis in FIG. 11 indicates a relative value with respect to the maximum illuminance (illuminance at the optical axis position). In the first position adjustment state, the illuminance is high at the central portion of the optical pupil E, and the illuminance is low in two steps at the peripheral portion (see range C). In the second position adjustment state, the illuminance is high at the center of the optical pupil E, and the illuminance is low at the periphery (see range B). On the other hand, in the image observation state, the image can be observed in the central portion of the optical pupil E, that is, in the range of A where the illuminance is high.

  In this way, by using the illuminance adjustment filter 32 that reduces the transmittance of the light transmitted through the peripheral portion 32 in two stages and switching the beam diameter by the diaphragm 31, it passes through the optical pupil E in the first position adjustment state. The illuminance within the pupil plane of the light to be emitted can be reduced in two steps from the center toward the periphery. Therefore, it becomes easier for the observer to adjust the position in the direction from the periphery to the center in the plane of the optical pupil E.

  In the present embodiment, the light beam diameter switching mechanism 30 is configured to switch the light beam diameter of the light source light in two steps in the position adjustment state, but the transmittance of the peripheral portion 32b of the illuminance adjustment filter 32 is set in three steps. By setting as described above and adjusting the area of the opening with the diaphragm 31, in the position adjustment state, the light beam diameter of the light source light can be switched to three or more stages, and φAli can be switched to three or more stages.

  In the present embodiment, the beam diameter switching mechanism 30 is configured by the diaphragm 31, the illuminance adjustment filter 32, the diffusion plate 33, and the drive unit 34. Is possible.

  Of course, it is possible to configure the video display device 1 and thus the HMD, or to adjust the position of the optical pupil E by appropriately combining the configurations of the above-described embodiments.

  The present invention is applicable to HMD.

(A) is sectional drawing which shows the structure in the position adjustment state of the video display apparatus which concerns on one Embodiment of this invention, (b) is sectional drawing which shows the structure in the video observation state of a video display apparatus. It is. It is a perspective view which shows the structure of the outline of HMD which has the said video display apparatus. (A) is explanatory drawing which expand | deploys and shows the optical path in the position adjustment state of the video display apparatus which concerns on other embodiment of this invention, (b) is the optical path in the video observation state of a video display apparatus. It is explanatory drawing which expands and shows. It is explanatory drawing which shows the light emission characteristic of the light source of the said video display apparatus. It is explanatory drawing which shows the permeation | transmission characteristic of the illumination intensity adjustment filter of the light beam diameter switching mechanism which the said video display apparatus has. It is explanatory drawing which shows the illumination characteristic in the pupil surface of an optical pupil. (A) is explanatory drawing which expand | deploys and shows the optical path in the position adjustment state of the video display apparatus based on further another embodiment of this invention, (b) is in the video observation state of a video display apparatus. It is explanatory drawing which expand | deploys and shows an optical path. (A) is explanatory drawing which expand | deploys and shows the optical path in the 1st position adjustment state of the video display apparatus based on further another embodiment of this invention, (b) is the 2nd of a video display apparatus. It is explanatory drawing which expand | deploys and shows the optical path in the position adjustment state of (2), (c) is explanatory drawing which expand | deploys and shows the optical path in the image | video observation state of a video display apparatus. In the said video display apparatus, it is explanatory drawing which shows the light emission characteristic of the light source which also considered the diffuser plate. It is explanatory drawing which shows the permeation | transmission characteristic of the illumination intensity adjustment filter of the light beam diameter switching mechanism which the said video display apparatus has. It is explanatory drawing which shows the illumination characteristic in the pupil surface of an optical pupil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Support means 4 Eyepiece optical system 7 Fixing mechanism (fixing means)
DESCRIPTION OF SYMBOLS 11 Light source 13 Display element 23 Hologram optical element 30 Light beam diameter switching mechanism (light beam diameter switching means)
31 Diaphragm 32 Illuminance Adjustment Filter 33 Diffuser 34 Drive Unit E Optical Pupil P Observer Eye R1 Video Display Area R2 Video Display Area T1 Effective Optical Path Area T2 Effective Optical Path Area

Claims (15)

A light source;
A display element that displays light by modulating light from a light source;
An image display device comprising an eyepiece optical system for guiding image light from a display element to an optical pupil,
In the image observation state where the observer observes the image at the position of the optical pupil, the light beam diameter of the light passing through the optical pupil is φView, and the optical position is adjusted in order to adjust the position of the optical pupil to the observer's pupil position. When the light beam diameter of the light passing through the pupil is φAli, it further includes a light beam diameter switching means for switching the light beam diameter of the light emitted from the light source so that φView <φAli.
An image display device, wherein the effective optical path region of the eyepiece optical system in the position adjustment state is included in the effective optical path region of the eyepiece optical system in the image observation state.   2. The video display device according to claim 1, wherein in the position adjustment state, the illuminance within the pupil plane of the light passing through the optical pupil is maximum at the center position.   3. The video display device according to claim 2, wherein the peripheral illuminance in the pupil plane of the light passing through the optical pupil in the position adjustment state is ½ or less of the central illuminance.   3. The video display device according to claim 2, wherein in the position adjustment state, the illuminance within the pupil plane of the light passing through the optical pupil decreases stepwise from the center toward the periphery.   5. The video display device according to claim 1, wherein the beam diameter switching unit switches the beam diameter of light emitted from the light source so that 3φView ≦ φAli.   6. The video display device according to claim 1, wherein the video display area of the display element is smaller in the position adjustment state than in the video observation state.   7. The image display device according to claim 1, wherein the light beam diameter switching means is disposed at a position substantially conjugate with the optical pupil.   8. The image display device according to claim 7, wherein the light beam diameter switching means has a diaphragm for switching the area of the opening between the image observation state and the position adjustment state. The beam diameter switching means further includes an illuminance adjustment filter for adjusting the illuminance in the pupil plane of the light emitted from the light source,
The video display device according to claim 8, wherein the illuminance adjustment filter reduces the transmittance of light transmitted through the peripheral portion rather than the transmittance of light transmitted through the central portion.   The video display device according to claim 9, wherein the illuminance adjustment filter reduces the transmittance of light transmitted through the peripheral portion in at least two stages.   The beam diameter switching means includes a diffusion plate that diffuses light from the light source, and a drive unit that disposes the diffusion plate in the optical path in the position adjustment state and removes the diffusion plate from the optical path in the image observation state. The video display device according to claim 7, wherein the video display device is provided.   12. The image display device according to claim 1, wherein the light beam diameter switching means switches the light beam diameter of the light emitted from the light source in at least two stages in the position adjustment state. The eyepiece optical system includes a volume phase reflection hologram optical element,
13. The hologram optical element according to claim 1, wherein the hologram optical element diffracts and reflects the image light from the display element and guides it to the optical pupil, and simultaneously transmits external light to the optical pupil. Video display device. A video display device according to any one of claims 1 to 13,
A head-mounted display comprising support means for supporting the video display device in front of an observer's eyes.   The support means includes a fixing means for fixing the relative position of the eyepiece optical system with respect to the head of the observer after performing position adjustment to match the position of the optical pupil of the eyepiece optical system with the position of the observer's pupil. The head mounted display according to claim 14.

Images