JP3085321B2 - Display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device used for a computer, a television receiver and the like.

[0002]

2. Description of the Related Art In recent years, a three-dimensional image (including a three-dimensional image) has been used as seen in the display of computer graphics.
There is a growing need for a technology for displaying an image, for example, a document “Image Lab November 1990, pp. 20-24”
As disclosed in U.S. Pat. No. 6,086,867, a system using binocular parallax is widely used as a three-dimensional display device. In addition, the method using binocular parallax is roughly classified into a glasses method and a method without glasses. The method without glasses is
For example, in the literature "Television Society Journal Vol. 44, No. 5,
Pp. 591 to 597, 1990 ", the use as a television receiver is considered from its generality.

On the other hand, the glasses system includes a method of using a simple polarizing plate and a color filter for the glasses, a method of providing a shutter function to the glasses, and a method of providing a two-dimensional display to the glasses.

In the eyeglass system, a method having a simple polarizing plate is generally used, such as a method of projecting two images having different polarizations on a large screen screen such as IMAX, or a two-dimensional image such as Sony Tektronix. There is a method in which a shutter for a polarizing filter is provided on the front surface of the display, and time-division driving is performed with the polarization direction changed.

[0005] In the glasses method, a two-dimensional display having glasses in glasses is described in, for example, a document "Image Lab".
As shown in Jan. 1991, pp. 29-33, and the document "Image Lab Jan. 1991, pp. 20-23", it is also called a head mounted display (HMD), Attention has been paid to the research of artificial reality.

[0006]

However, most of the various types of display devices described above are three-dimensional displays using only binocular parallax.
Since the stereoscopic display is performed using so-called illusion using only information of binocular parallax, an eye adjustment mechanism (a mechanism such as focus adjustment) and a convergence mechanism (a movement mechanism for gazing at an object) often do not match. In general, there has been a drawback that if the user keeps watching the display for more than 20 minutes, eye fatigue accumulates. FIG. 16 is a diagram for explaining this state. For example, two images P1 and P2 are displayed on the screen 210 at a predetermined interval Z, and the two images P1 and P2 are displayed by human eyes. 201,
When the eyes 201 and 202 perform binocular vision, the adjustment mechanism of the eyes 201 and 202 focuses on the actual distance L1 from the eyes 201 and 202 to the screen 210, but the convergence mechanism of the eyes 201 and 202 Facing the image P2, the other eye 20
Since the eyes 201 and 202 are controlled so that 2 faces the image P1, the gazing point is at the intersection position CLS, and in the example of FIG. 16, it is closer to the actual screen. Therefore,
Distance L1 for focusing and distance L2 to the point of regard CLS
Does not match, it is considered that this causes eye fatigue. If the screen is viewed for a long time, the larger the difference between L1 and L2, the greater the accumulation of eye fatigue.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device capable of displaying a stereoscopic image with less eyestrain and richness in a simple manner in a simple manner.

[0008]

According to a first aspect of the present invention, there is provided a display device, wherein a minute lens is provided in front of each dot of at least one pixel forming a two-dimensional display. The optical path length between the minute lens and the dot is set to be longer than the focal length of the minute lens and to be equal to or less than twice the focal length.

The display device according to the present invention is further characterized in that a means for changing the optical path length is provided between the minute lens and the dot.

The display device according to a third aspect of the present invention is further characterized in that a means for changing a focal length of the minute lens is further provided.

[0011]

According to the display device of the present invention, a minute lens is provided in front of each dot composed of at least one pixel forming a two-dimensional display. By setting the optical path length larger than the focal length of the minute lens and twice or less of the focal length, the real image of the dot can be enlarged and displayed in front of the two-dimensional display.

A display device according to a second aspect of the present invention is the display device according to the first aspect,
Further, a means for changing the optical path length is provided, so that the position of the real image of dots can be changed for the entire screen or for each dot.

According to a third aspect of the present invention, there is provided a display apparatus as set forth in the first aspect.
Further, a means for changing the focal length of the minute lens is provided. Also in this case, the position of the real image can be changed for the entire screen or for each dot by the above means.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are a front view and a sectional view, respectively, of a first embodiment of a display device according to the present invention. 1 and 2, the two-dimensional display DP has dots 2a, 2b, and 2c formed of one pixel, and the two-dimensional display DP is provided with a front glass 3. Furthermore, in this display device, 2
Micro lenses 1a, 1b, 1c are provided in front of the dots 2a, 2b, 2c of the dimensional display DP in correspondence with the dots 2a, 2b, 2c.

The minute lenses 1a, 1b, 1c are lenses having a focal length of f, and are minute lenses 1a, 1b, 1c.
The optical path length S1 between c and the dots 2a, 2b, 2c is set to a value larger than the focal length f of the lenses 1a, 1b, 1c and less than twice the focal length f. By setting in this way, in this embodiment, when the observer sees each dot 2a, 2b, 2c of the two-dimensional display DP with the eyes 5 using the micro lenses 1a, 1b, 1c,
It is intended to display the inverted real images 2a ', 2b', 2c 'of each dot in front of the microlenses 1a, 1b, 1c.

In such a configuration, the minute lens 1
a, 1b, and 1c are thin lenses, the thickness of the front glass 3 is 0 mm for convenience of calculation, and the minute lenses 1a, 1b, and 1c
Assuming that the refractive index of the gap between the lens and the front glass 3 is "1", the minute lenses 1a, 1b, 1c and the inverted real images 2a ', 2b',
The distance S2 from the microlenses 1a, 1c
The focal length f of b, 1c and the distance S1 between the dots 2a, 2b, 2c and the microlenses 1a, 1b, 1c are obtained as in the following equation.

[0017]

1 / S2 = -1 / f + 1 / S1

The magnification β of the inverted real images 2a ′, 2b ′, 2c ′ is determined by the distance x ′ between the front focal point F ′ of the minute lenses 1a, 1b, 1c and the inverted real images 2a ′, 2b ′, 2c ′. When the distance between the back focus F of the micro lenses 1a, 1b, 1c and the dots 2a, 2b, 2c is x, the distance can be obtained by the following equation.

[0019]

(Equation 2)

Now, for example, the minute lenses 1a, 1b, 1c
Is 3 mm, the distance S1 between the lens and the dot is 5 mm.
mm and the distance S2 between the inverted real image and the lens is 7.5 mm, the enlargement magnification β is 1.5 times by the above equations (1) and (2).

If the distance D between the eye 5 of the observer and the lens is 400 mm, 392.5 mm from the eye 5 of the observer.
The inverted real image of the dot can be seen at a distance of, and the position of the real image can be changed by 7.5 mm before the lens. Therefore, when an image including a plurality of these dots is viewed, it is possible to make the image appear as if it were in front of the lens surface.

When the optical path length S1 between the lens and the dot is smaller than the focal length f of the minute lens, an erect virtual image is formed behind the lens and the image cannot be seen in front of the lens. Therefore, at least the optical path length S1 between the lens and the dot needs to be larger than the focal length f of the lens in order to show an image before the lens. However, the optical path length S1 between the lens and the dot is set to the focal length of 2
When the optical path length S1 is further increased, the magnification β becomes 1
Less than twice, the dots seen by the lens become smaller,
The image deteriorates significantly.

Accordingly, in order to show an image in front of the lens without deteriorating the image, the optical path length S1 between the lens and the dot is set to be larger than the focal length f, and the focal length f is set to two.
Must be set to less than twice.

FIG. 3 is a diagram showing an example of a display device in which a means for changing the optical path length is added to the display device having the structure shown in FIGS. 1 and 2. In this display device, the means for changing the optical path length is used. , A panel PN1 of a two-dimensional display DP and minute lenses 1a, 1b,
An actuator AT1 that changes the distance Z between the panel PN2 and the panel PN2 having 1c,.

In such a configuration, the actuator AT
1, the distance Z between the panel PN1 and the panel PN2
By changing the optical path length, the position of the visible inverted real image can be changed. FIG.
(A) to (d) are diagrams specifically showing this state.
FIG. 4A shows a state of an inverted real image, for example, 2b 'when the focal length f of the microlens is 3 mm, the distance S1 between the lens and the dot is 5 mm, and the distance S2 between the inverted real image and the lens is 7.5 mm. FIG. In this case, the inverted real image 2b 'is located at a position of 392.5 mm from the observer's eye 5 when the magnification β is 1.5 times and the distance D between the observer's eye 5 and the lens is 400 m. You can see this image.

FIG. 4B shows an inverted real image when the focal length f of the microlens is 3 mm, the distance S1 between the lens and the dot is 6 mm, and the distance S2 between the inverted real image and the lens is 6 mm.
For example, it is a diagram showing a state of 2b '. In this case, the inverted real image 2b ′ has an enlargement magnification β of 1.0 ×, and when the distance D between the observer's eye 5 and the lens is 400 m, the image is located 394 mm from the observer's eye 5. Can be seen.

FIG. 4C shows an inverted real image when the focal length f of the minute lens is 3 mm, the distance S1 between the lens and the dot is 7.5 mm, and the distance S2 between the inverted real image and the lens is 5 mm, for example. It is a figure which shows the state of 2b '. In this case, the inverted real image 2b ′ has an enlargement magnification β of 0.667 ×
When the distance D between the observer's eye 5 and the lens is 400 m, this image can be seen from the observer's eye 5 at a position of 395 mm.

FIG. 4D shows an inverted real image when the focal length f of the microlens is 3 mm, the distance S1 between the lens and the dot is 4 mm, and the distance S2 between the inverted real image and the lens is 12 mm, for example, 2b '. It is a figure showing the state of. In this case, the inverted real image 2b 'has an enlargement magnification β of 3 times, and when the distance D between the eye 5 of the observer and the lens is 400 m, the image is viewed at a position of 388 mm from the eye 5 of the observer. be able to.

As described above, when the optical path length S1 between the minute lens and the dot is changed within a range larger than the focal length f of the minute lens, the position of the dot, that is, the position of the real image seen by the observer is changed. Can be.

FIG. 5 is a diagram showing a change in S2 when S1 is changed. As can be seen from Equation 1 and FIG. 5, the optical path length S1 is actually larger than the focal length f as described above. Even if it is changed in the range, the distance S2 between the real image and the lens can be changed only in a range smaller than the focal length f (see ΔS2 in FIG. 5). However, as can be seen from FIG. 5, as the optical path length S1 is closer to the focal length f, the distance at which the real image can be viewed can be greatly changed toward the observer.

When the optical path length S1 between the minute lens and the dot is set to a value twice or more the focal length f as shown in FIG. 4C, as described above, the dot enlargement magnification .beta. Since it is smaller than 1, the quality of the image formed of these dots deteriorates, which is not preferable.

On the other hand, the apparent magnification m seen from the eye 5 is
It is proportional to the viewing angle of the object. For this reason, for example, FIG.
, The visual angle of the dot is u, the visual angle of the real image is u ′, and the size of the dot is y, the apparent magnification m is given by the following equation.

[0033]

M = tan (u ′) / tan (u) tan (u) = y (D + S1) tan (u ′) = y × β / (D−S2)

In this case, as shown in the above example, D
(E.g., 400 mm) is larger than s1 and s2, so that the influence of the magnification β becomes large, and the apparent magnification m
Is 1.55 times larger and looks as if there is a dot 7.5mm before the lens. However, since a substance having a diffusing effect is not provided on the image plane, what is actually observed with the eyes is as shown in FIG. This is a portion cut by the viewing angle, and unless the distance between the lens and the eye is very small, the adjacent lenses do not affect the image seen by the eye.

That is, when the magnification β is larger than 1 as shown in FIGS. 4A and 4D, only the dots within the range cut off by the viewing angle between the lens and the eyes can be seen. In addition, although flare light and variations in dots are problematic, adjacent dots do not directly affect.

In the above-described example, the distance between the panel PN1 of the two-dimensional display DP and the panel PN2 having the microlenses 1a, 1b, 1c,... Is changed by the actuator AT1. Although the overall distance (optical path length) between the dot and each microlens was changed, a microactuator was provided to change the distance between each lens and each dot for each lens. If the distance (optical path length) is changed, it is possible to display a stereoscopic image in which the distance of the real image is changed for each dot by changing the distance of the real image for each dot.

Further, without mechanically moving the panel PN1 of the two-dimensional display DP and the panel PN2 having the minute lens (ie, without changing the actual distance between the lens and the degree (ie, without changing the lens). Means for changing the optical path length (without changing the actual distance between dots) can also be configured.

FIG. 6 is a diagram showing an example of the configuration of a display device in which a material whose refractive index changes by applying a voltage is provided in the optical path length. That is, the display device of FIG. 6 further includes a material 23 having an electro-optical effect and transparent electrodes 24a and 24b on the front glass 3 of the two-dimensional display DP.
And a protective glass 25 are provided.

As a material whose refractive index is changed by applying a voltage, a material having an electro-optic effect is known. For example, an inorganic compound such as LiNbO ₃ or PLZT ceramic or an organic compound such as liquid crystal or organic polymer is used. is there.

In such a display device, the electrode 2
By changing the applied voltage between 4a and 24b, the refractive index of the material 23 having the electro-optical effect can be easily changed continuously. Since the optical path length is the product of the actual distance and the refractive index, by changing the refractive index of the material 23 having the electro-optical effect, the optical path length can be changed without changing the actual distance. As a result, accurate control of the optical path length can be performed. Further, since the optical path length can be changed by a voltage, a simple structure in which electrodes are formed at both ends of a material having an electro-optical effect is sufficient.

Now, for example, a material 23 having an electro-optical effect
Is used, the actual distance between the lens and the dot is 4 mm, and the thickness of the liquid crystal is 2 mm. Further, for convenience of calculation, it is assumed that the thickness of the glass is 0 mm, and that there is no refraction of light rays in portions other than the lens.

In this case, when a certain voltage is applied to the electrodes 24a and 24b to change the refractive index n of the liquid crystal to 1.5, the optical path length in the liquid crystal having a thickness of 2 mm becomes 2 × 1. 5 = 3
mm, and the optical path length S1 between the lens and the dot is 5 mm. FIG. 7A illustrates this state. When the refractive index n of the liquid crystal is 1.5 and the optical path length S1 is 5 mm, FIG.
The distance S2 between the inverted real image, for example, 2b 'and the lens, for example, 1b, is 7.5 mm.

When the applied voltage is further changed from this state to make the refractive index n of the liquid crystal 1.8, the optical path length in the liquid crystal having a thickness of 2 mm becomes 2 × 1.8 = 3.6 mm, and the lens The optical path length S1 between the dot and the dot is 5.6 mm. FIG.
(B) is a diagram showing this state. When the refractive index n of the liquid crystal is 1.8 and the optical path length S1 is 5.6 mm, the distance S2 between the inverted real image 2b ′ and the lens 1b is 6.46 mm. Become.

As described above, when the refractive index n of the liquid crystal is changed from 1.5 to 1.8, the distance between the lens and the real image becomes 1.0.
Can be changed by 4mm. At this time, the optical path length S1
Is close to the focal length f, the position of the real image can be greatly changed by a change in the optical path length S1 due to a slight change in the refractive index, and the distance of the real image seen from the eye 5 can be greatly changed.

Further, the configuration shown in FIG. 6 can be modified to a configuration as shown in FIG. That is, FIG.
Then, the electrodes 28a and 29a are formed corresponding to the dots 2a, the electrodes 28b and 29b are formed corresponding to the dots 2b, and the electrodes 28c and 29c are formed corresponding to the dots 2c. Thus, voltage control corresponding to each dot can be performed. In this case, the optical path length can be changed for each dot, and the distance of the real image can be changed for each dot, as in the case of providing the microactuator described above, and a stereoscopic image can be displayed. Becomes

Although a liquid crystal has been described as an example of a material having an electro-optic effect, when other electro-optic materials are used, the optical path length is changed and the distance of the real image is changed in the same manner as the liquid crystal. Can be. In this case, when using PLZT ceramics or the like, there is an advantage that it is more suitable for increasing the area than when using other crystalline materials.

As described above, by using a material whose refractive index changes by applying a voltage as a means for changing the optical path length, the structure is simpler and simpler than when an actuator is used. Control can be performed. In particular, when the optical path length is changed for each dot, a material having such an electro-optical effect is preferably used because a simple structure is required and good controllability is obtained.

The position of the inverted real image can also be changed by changing the focal length f of the minute lens instead of changing the optical path length S1 between the lens and the dot.

FIG. 9 is a view showing an example of a display device in which a means for changing the focal length f of a minute lens is added to the display device having the structure shown in FIGS. 1 and 2. In this display device, a plurality of minute A panel PN4 having a converging lens and a panel PN5 having a plurality of minute converging lenses are provided as a variable-focus optical system, that is, a zoom optical system (two-group zooming of a conical lens). The distances Z1 and Z2 between the actuator AT
2 to change.

In the display device having such a configuration,
Panel PN4 and panel PN by actuator AT2
By changing the distances Z1 and Z2 between the lens 5 and the panel PN1, the focal length f of the variable-focus optical system, that is, the minute lens is changed, and the distance S2 between the inverted real image and the lens is calculated based on Equation 1. And the position of the visible real image can be changed.

FIGS. 10A to 10C specifically show this state. FIG. 10A shows that the distance S1 between the dot and the minute lens is 5 mm and the focal length f of the minute lens is
FIG. 6 is a diagram showing an inverted real image when 3 mm is 3 mm, for example, a state of 2b ′. In this case, the position S2 of the inverted real image 2b '
Is 7.5 mm, and the magnification β is 1.5 times.

FIG. 10B is a diagram showing an inverted real image, for example, the state of 2b 'when the distance S1 between the dot and the minute lens is 5 mm and the focal length f of the minute lens is 2.5 mm. is there. In this case, the position S of the inverted real image 2b '
2 is 6 mm, and the magnification β is 1.

FIG. 10C is a diagram showing an inverted real image, for example, the state of 2b 'when the distance S1 between the dot and the minute lens is 5 mm and the focal length f of the minute lens is 3.5 mm. is there. In this case, the position S of the inverted real image 2b '
2 is 11.67 mm, and the magnification β is 2.3 times.

In the above-described example, the distance between the panel PN1, the panel PN4, and the panel PN5 of the two-dimensional display DP is changed by the actuator AT2, so that the focal lengths of all the microlenses are changed to be the same as a whole. However, by providing a microactuator that changes the focal length of each lens for each lens and changing the focal length for each lens, the distance of the real image can be changed for each dot. Thus, it is possible to display a stereoscopic image in which the distance of the real image is changed for each dot.

Further, each of the above panels PN1, PN4, PN
Means for changing the focal length without mechanically moving the lens 5 can also be configured.

FIG. 11 is a diagram showing an example of the configuration of a display device in which each minute lens is formed of a material whose refractive index changes when a voltage is applied. That is, in the display device of FIG. 11, the microlenses 22a, 22b, and 22c are formed of a material having an electro-optical effect (electro-optical material), and the electrodes 20a are provided between the microlenses 22a, 22b, and 22c. , 20b are arranged.

As the electro-optical material, for example, LiN
The microlenses 22a and 22b are made of a bO ₃ crystal so that an electric field can be applied along the optical axis by the electrodes 20a and 20b.
b, 22c are formed. In this case, the electrodes 20a,
When a high voltage is applied between the microlenses 22a and 20b,
2b and 22c are electro-optical lenses.

In the display device having such a configuration,
By changing the voltage between the electrodes 20a and 20b, the focal length of the minute lenses 22a, 22b and 22c can be changed, and the position of the real image can be changed.
Note that, as described above, a material having an electro-optic effect can be used as a material whose refractive index changes by application of a voltage.

In the display device shown in FIG. 12, the minute lenses 30a, 30b and 30c are composed of minute liquid crystal lenses 31a, 31b and 31c in which a kind of nematic liquid crystal having a relatively large refractive index is sealed, and transparent electrodes 32a and 31c. 32
b, 32c; 33a, 33b, 33c, and flat glass 34a, 34b, 34c; 35a, 35b, 35c.

In the display device having such a configuration, the electrodes 32a, 32b, 32c and the electrodes 33a, 33c are also provided.
b, 33c to apply a voltage to the minute liquid crystal lens 31.
By controlling the alignment states of the liquid crystal molecules a, 31b, and 31c, the refractive index of the liquid crystal can be changed, the focal length can be continuously changed, and the position of the real image can be changed.

In addition, for example, a liquid crystal material is sealed between a plate electrode and a circular or elliptical hole and a non-uniform liquid crystal material is applied when a voltage is applied between the electrodes. It is also possible to change the focal length of the minute lens by forming a minute lens based on the orientation of the liquid crystal molecules due to an appropriate electric field distribution and changing the applied voltage. Alternatively, the variable focus lens can be constituted by a liquid crystal lens having a Fresnel structure.

In the above-described embodiment, as shown in FIG. 1, one minute lens is provided for each dot consisting of one pixel forming the two-dimensional display DP. As shown in FIG. 14, one microlens may be provided for each dot composed of a plurality of pixels, and in this case, the present invention can be similarly applied.

That is, in the configuration example of FIG.
A minute lens 1e is provided for each dot 2e composed of three pixels of red (RGB), green (G), and blue (B). At this time, hue information can be displayed with high accuracy only when there are three pixels of RGB.
Compared to the case where a micro lens is provided for each pixel, there is no significant change in performance, and it is easy to create a micro lens as much as the diameter of the lens can be increased.

Further, in the configuration example shown in FIG. 14, a set of four dots 2f, 2g, 2h, and 2i composed of three pixels of RGB is newly set as one dot, and a minute lens 1f is provided for each dot.
Is provided. In this case, although the display accuracy of the information of the fine line and the contour is somewhat lowered, the diameter of the lens can be further increased, so that a minute lens can be easily formed. Furthermore, instead of using four dots as one dot, 3 × 3 = 9 sets can be used as one dot.

In the case of FIGS. 1 and 13, ie, when one dot is composed of one pixel or three pixels of RGB, one dot is used.
Since one dot is one piece of information, no problem occurs when the image is an inverted image. However, in the case of FIG.
When a plurality of sets of dots composed of B3 pixels are used, it is necessary to display an image in an inverted state at least for each of the three RGB pixels in one dot.

In each of the above-described embodiments, FIG.
The display device of FIGS. 6, 7, 8, 11 and 12 can be used to change the optical path length or the focal length for each dot without changing the optical path length or the focal length.
The optical path length over the entire dot area for one column or one row,
Or, when it is configured to change the focal length, it is suitable for applications that provide a gentle three-dimensional effect in a wide area. More specifically, when only three types of changes, that is, the distant view, the middle view, and the near view need not be given, by using these configurations, the optical path length, Alternatively, the focal length can be set to be the same for a distant view, and the optical path length or the focal length can be set to be the same for all the dots in the foreground area for the foreground.

On the other hand, when these display devices are configured such that the optical path length or the focal length can be changed for each dot, the optical path length or the focal length can be changed over a fine screen. It is suitable for use, and in this case, a three-dimensional effect can be obtained for each dot.

However, in any of the above cases, the focal length of the micro lens corresponding to each dot or the lens acting on the entire surface of the two-dimensional display DP, or
Since the refractive index of the layer between these lenses and the dots can be easily set to a predetermined value, according to the image information to be displayed, by determining the focal length or the refractive index,
Even when the two-dimensional display DP is used, three-dimensional display is possible, and by applying any of the above-described display devices to the three-dimensional display device, an image can be displayed at the distance of the gazing point even in stereoscopic viewing with binocular parallax. By forming an image, eye fatigue can be reduced.

FIGS. 15A and 15B are diagrams for explaining this situation. For example, on the two-dimensional screen 210, 2
The two images P1 and P2 are displayed at a predetermined interval Z, and when these two images P1 and P2 are observed, FIG.
15A shows a state in which the image P2 is viewed by one eye 201, and FIG. 15B shows a case in which the image P1 is viewed by the other eye 202. FIG. The convergence mechanism of the eyes 201 and 202 is shown in FIG.
, And the eyes 201 and 202 are controlled so that the other eye 202 faces the image P1. Therefore, the gazing point is the intersection position CLS thereof, and in the example of FIGS. 15 (a) and (b), , On the near side of the actual screen 210. In such a case, the display device according to the present invention is mounted for the left eye and the right eye, respectively, and the display device is controlled in accordance with the image information of the screen 210, so that the screen 2
Since the positions of the ten images P1 and P2 (the real image positions in this case) can be moved to the position of the gazing point CLS,
As a result, the adjusting mechanism of the eyes 201 and 202
The eyes 201 and 202 are controlled so as to focus on the distance L2 from the point of interest 1,202 to the gazing point CLS. As a result, the eye convergence and the accommodation can be matched, and eye fatigue can be reduced.

Also, contrary to the above example, the gazing point CLS is the actual distance L1 from the eyes 201, 202 to the screen 210.
When an image at a longer distance is displayed on the screen 210, the display device is configured to display a virtual image of the image of the screen 210, and the display device is controlled so that the virtual image is displayed at the point of gaze. By doing so, eye convergence and accommodation can be matched in the same way, and fatigue can be reduced.

[0071]

As described above, in the display device according to the first aspect, the optical path length between the minute lens and the dot is larger than the focal length of the minute lens and twice the focal length. Since the following settings are made, the real image of the dots seen by the observer can be set ahead of the two-dimensional display, and at the same time, the real image can be enlarged and displayed.

Further, in the display device according to the second aspect, since means for changing the optical path length is provided between the minute lens and the dot, the position of the real image of the dot can be changed for the entire screen or for each dot. In addition, when a three-dimensional display is configured using this display device, by appropriately changing the optical path length and appropriately changing the image position, eye fatigue is reduced and the sense of reality is enhanced. A stereoscopic image can be easily displayed.

Further, in the display device according to the third aspect, since the means for changing the focal length of the minute lens is provided, the position of the real image of the dot can be determined on the entire screen or on one screen.
It can be changed for each dot, and furthermore, when a three-dimensional display is configured using this display device, by appropriately changing the focal length and appropriately changing the image position, eye fatigue is reduced and realism is reduced. A rich three-dimensional image can be easily displayed.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment of a display device according to the present invention.

FIG. 2 is a sectional view of a first embodiment of the display device according to the present invention.

FIG. 3 is a diagram showing an example of a display device to which means for changing an optical path length is further added.

FIGS. 4A to 4D are diagrams for explaining a state when an optical path length is changed.

FIG. 5 is a diagram illustrating a relationship between an optical path length and a position of an inverted real image.

FIG. 6 is a diagram showing a configuration example of a display device in which a material whose refractive index changes by applying a voltage is provided in an optical path.

FIGS. 7A and 7B are diagrams for explaining a state when the optical path length is changed by changing the voltage in the configuration of FIG. 6;

FIG. 8 is a diagram showing a modification of the display device of FIG.

FIG. 9 is a diagram showing an example of a display device to which means for changing the focal length of a lens is further added.

FIGS. 10A to 10C are diagrams for explaining a state when a focal length of a lens is changed.

FIG. 11 is a diagram illustrating a configuration example of a display device in which a minute lens is formed of a material whose refractive index changes by applying a voltage.

FIG. 12 is a diagram showing a modification of the display device of FIG. 11;

FIG. 13 is a diagram showing a modification of the arrangement of dots and minute lenses.

FIG. 14 is a diagram showing a modification of the arrangement of dots and minute lenses.

FIGS. 15A and 15B are diagrams for explaining the principle of matching eye convergence and accommodation according to the present invention.

FIG. 16 is a diagram for explaining a general relationship between eye convergence and accommodation.

[Explanation of symbols]

1a, 1b, 1c, 1e, 1f
Micro lens 2a, 2b, 2c, 2e, 2f, 2g, 2h, 2i
Dots 2a ', 2b', 2c '
Inverted real image 3
Front glass 20a, 20b
Electrodes 22a, 22b, 22c
Micro lens 23
Materials 24a, 24b having electro-optic effect
Electrode 25
Protective glass 27
Electro-optic lens 30a, 30b, 30c
Micro lens 31a, 31b, 31c
Micro liquid crystal lens 32a, 32b, 32c, 33a, 33b, 33c
Transparent electrodes 34a, 34b, 34c, 35a, 35b, 35c
Flat lens DP
2D display PN1, PN2, PN4, PN5
Panel AT1, AT2
Actuator

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 13/00-15/00

Claims (3)

(57) [Claims] 1. A minute lens is provided in front of each dot of at least one pixel forming a two-dimensional display, and an optical path length between the minute lens and the dot is small. The display device is set to be larger than the focal length of the lens and to be set to twice or less of the focal length. 2. The display device according to claim 1, further comprising means for changing an optical path length between the minute lens and the dot. 3. The display device according to claim 1, further comprising means for changing a focal length of said minute lens.