JP2002122806A - Display device and enlarged picture forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device where reflected light from a user is intercepted and the utilization efficiency of light for displaying picture is improved. SOLUTION: A correction lens 12 correcting an optical path and a reflection type linearly polarizing plate 13 are arranged in front of a display element 11 on which picture is displayed. The plate 13 is arranged so that linearly polarized light from the element 11 may be reflected. A 1/4 wavelength plate 14 and a concave mirror 15 are arranged in sequence so as to face to the plate 13 on an optical path where emitted light from the element 11 is reflected by the plate 13. By adjusting polarization by the plate 13 and the plate 14, the emitted light from the element 11 is visually confirmed by the user in a state where light quantity is hardly lowered in the optical path. The plates 13 and 14 function as a circularly polarized light selection element for the reflected light from an illuminated user's face 17, thereby, the reflected light is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device that allows a user to visually recognize an enlarged image as a virtual image, and a method for generating such an enlarged image. The present invention relates to a display device that is used by placing it near a head, or the like, and an enlarged image generation method for generating an enlarged image displayed on such a display device.

[0002]

2. Description of the Related Art In recent years, there has been known a display device which can visually sense an enlarged virtual image of an image input from a computer device, a video device, or the like, so that the user can feel as if he / she is looking at a large screen such as a 50-inch screen 2 meters away. I have. This display device has an opening in which a display unit is installed,
The user uses this display device by mounting it on the head or placing it near the head. When worn on the head, for example, a pad is provided in the opening, by pressing this pad against the user's forehead and hanging on the head, wearing the display device as if wearing glasses, An enlarged virtual image displayed on a portion of the glasses corresponding to the lens is visually recognized. In the case of disposing it near the head, for example, it is used by bringing the face close to the opening and looking inside.

Hereinafter, a schematic configuration of such a conventional display device will be described. FIG. 8 shows a configuration example of an optical system of a conventional display device. In the optical system of the display device 80 shown in FIG. 8, a correction lens 12 for correcting an optical path and a half mirror 81 are arranged in front of a display element 11 on which image information from a video device or the like is displayed. As the display element 11, for example, a transmissive or reflective liquid crystal display panel (L
A CD (Liquid Crystal Display, hereinafter abbreviated as LCD) is used, and linearly polarized light is emitted using a linearly polarizing plate. Also, the half mirror 81
With respect to the axis of light by the image displayed on the display element 11,
It is arranged in an inclined state. On the optical path reflected by the half mirror 81, the concave mirror 15 is arranged to face the half mirror 81.

In the display device 80 having such a configuration,
When an image is displayed on the display element 11, the light 80 of the image is displayed.
The optical path a is corrected by the correction lens 12, enters the half mirror 81, and is reflected. This reflected light 80b
Is incident on the concave mirror 15, and the light 80c reflected by the concave mirror 15 is incident again on the half mirror 81.
The light 80c passes through the half mirror 81 and is emitted to the outside, reaches the user's pupil 16 and forms an image, thereby generating an enlarged virtual image for the user.

[0005]

However, in the configuration of the optical system such as the above-described display device 80, the user's face 17 is illuminated by light emission of the display element 11 or light from outside the display device 80. A phenomenon occurs in which the user's face 17 is reflected in a target virtual image as viewed from the user. To illustrate this, FIG. 9 shows the optical path of light from the illuminated user's face 17.

FIG. 9 shows a configuration similar to that of the optical system shown in FIG. When the user's face 17 is illuminated by the light from the display element 11 or the light from outside the display device 80, the light 90a from the user's face 17 due to this is illuminated.
Is incident on the inside of the display device 80 as reflected light. This light 90a passes through the half mirror 81 and reaches the concave mirror 15. Light 90b reflected by concave mirror 15
Reaches the user's pupil 16 again through the half mirror 81. At this time, the concave mirror 15 emits light 90 from the user.
Since the user works as a magnifying glass with respect to a, the user visually recognizes a display in which the user's face 17 overlaps a target virtual image, and the display quality is greatly impaired.

As a conventional method for preventing the reflection of the user's face 17, a method of arranging a circularly polarized light selecting element in the optical path between the user's face 17 and the concave mirror 15 has been considered. . For example, this circularly polarized light selection element is a counterclockwise circularly polarized light (LCP: Left-handed Circularly Polarized).
light (hereinafter, abbreviated as LCP), the light 90a from the face 17 of the user is
Out of the mirror 15, this LCP is transmitted through the concave mirror 15.
Incident on. The light 90b reflected by the concave mirror 15 is converted into clockwise circularly polarized light (RCP: Right-handed Circuit).
larly Polarized light (hereinafter abbreviated as RCP). This light 90b is incident again on the circularly polarized light selecting element, but the circularly polarized light selecting element does not transmit through the RCP, so that the reflected light is cut off and does not reach the pupil 16 of the user.

An example of a display device using such a circularly polarized light selection element will be described below. FIGS. 10A and 10B show an example of the configuration of an optical system of a display device using a circularly polarized light selection element. FIG. 10A shows a first example, FIG. 10B shows a second example, and FIG. 10C shows a third example. Here is an example.

In the first configuration example of the optical system shown in FIG. 10A, an absorption linear polarizing plate 101 is used as a circularly polarized light selecting element.
And a quarter-wave plate 102 are used in combination, and these are arranged between the half mirror 81 and the pupil 16 of the user. The absorption linear polarizing plate 101 is obtained by orienting a dichroic dye such as iodine on a stretched film such as PVA (polyvinyl alcohol). Assuming that the light emitted from the display element 11 is linearly polarized light, the light of the image displayed on the display element 11 is reflected in the direction of the concave mirror 15 by the half mirror 81 after the optical path is corrected by the correction lens 12. The light of this image is reflected by the concave mirror 15 and re-enters the half mirror 81, passes through the half mirror 81 and is incident on the quarter-wave plate 102. The transmitted light here is converted into circularly polarized light, subsequently enters the linear polarizing plate 101, and only the component along the transmission axis is transmitted, and the transmitted light reaches the user's pupil 16 to display an image.

The reflected light from the user is converted into circularly polarized light by the absorption-type linear polarizing plate 101 and the quarter-wave plate 102. The helical direction of the circularly polarized light may be either direction, and is equal to the transmission axis direction of the absorption type linear polarizing plate 101 and １ ／.
It is determined by the relative relationship with the slow axis direction of the wave plate 102. Here, it is assumed that the reflected light becomes an LCP after passing through the circularly polarized light selection element. The reflected light of the user's face 17 illuminated by the output light of the display element 11 or the external light transmits only the linearly polarized light transmitted through the transmission axis of the absorption type linearly polarizing plate 101, and is transmitted by the 波長 wavelength plate 102.
It is converted into a CP and reaches the half mirror 81. Half of this LCP light is reflected by the half mirror 81 toward the lower side of the lens barrel (not shown) in the figure, and the other half passes through the half mirror 81 and enters the concave mirror 15. The light of this LCP is reflected by the concave mirror 15 to be RC.
It is converted to P and reaches the half mirror 81. The RCP light transmitted through the half mirror 81 again is
2 is converted to linearly polarized light by the absorption linear polarizing plate 10
1, the direction of polarization of this linearly polarized light is the direction absorbed by the absorption type linear polarizing plate 101. For this reason, this light does not transmit to the user side, and the reflected light is removed.

In the optical system shown in FIG. 10A, a quarter-wave plate 103 shown by a broken line in the figure may be arranged between the display element 11 and the correction lens 12. In this case, the linearly polarized light emitted from the display element 11 is 1/4.
The light is converted into circularly polarized light by the wave plate 103 and passes through the correction lens 12. For example, as described above, when the circularly polarized light selection element including the absorption linear polarizer 101 and the quarter-wave plate 102 is configured to transmit the LCP, the light emitted from the display element 11 is changed to the quarter-wave plate 103. By RCP
The arrangement is such that The RCP light is reflected by the half mirror 81 and enters the concave mirror 15, is reflected and converted into LCP, passes through the half mirror 81, and
The light enters the four-wavelength plate 102. Light that has passed through the quarter-wave plate 102 and has become linearly polarized light has all passed through the absorption-type linear polarizing plate 101 and reaches the user's pupil 16. Further, there is no change in the optical path of the reflected light from the user.

In the configuration shown in FIG. 10A, the light emitted from the display element 11 remains linearly polarized while passing through the correction lens 12, the half mirror 81, the concave mirror 15, and the half mirror 81. Therefore, after being converted into circularly polarized light by transmission through the ４ wavelength plate 102, 吸収 of the component is absorbed by the absorption linear polarizing plate 101,
The brightness of the displayed image is reduced by half. However, 1
With the configuration in which the 波長 wavelength plate 103 is added, all of the light emitted from the display element 11 is converted into circularly polarized light, and the circularly polarized light enters the 円 wavelength plate 102 to become linearly polarized light. 101, the absorption type linearly polarizing plate 1
No absorption of light occurs when 01 is transmitted, and a decrease in the brightness of the displayed image can be suppressed.

Next, the second optical system of the optical system shown in FIG.
In the configuration example shown in FIG. 10, an absorption linear polarizer 104 and a 波長 wavelength plate 105 are arranged between the half mirror 81 and the user's pupil 16. In the configuration shown in FIG. The configuration is such that the positions of the polarizing plate 101 and the 1/4 polarizing plate 102 are interchanged. This optical system is suitable when the amount of reflected light due to external light is small, that is, when the light illuminating the user's face 17 can be regarded as almost only light from the display element 11. In this case, the light illuminating the user's face 17 passes through the absorption linear polarizer 104 and the 波長 wavelength plate 105 while exiting the display element 11 and reaching the user's face 17. It is polarized. Assuming that this light is LCP, the light reflected by the user's face 17 changes its phase by 180 ° to become RCP, and the vibration direction of the linearly polarized light that has been transmitted through the quarter-wave plate 105 again and converted is Since this is orthogonal to the transmission axis direction of the linear polarizing plate 104, the linearly polarized light is absorbed by the absorption linear polarizing plate 104 and is not transmitted. Therefore, the reflected light of the user's face 17 does not reach the concave mirror 15, and the reflected light is blocked.

In the case of the optical system shown in FIG. 10B, the external light that illuminates the user's face 17 is considered to be natural light, so that the reflected light from the user's face 17 is not reflected. Of these, one half of the component is transmitted through the absorption linear polarizing plate 104. Thereafter, the light passes through the half mirror 81 twice, so that the amount of light is further reduced to ４ and reaches the absorption type linear polarizing plate 104 again. This light is absorbed by an absorption type linear polarizer 104.
The light passes through the 波長 wavelength plate 105 and reaches the user's pupil 16, but the reflected light at this time is suppressed to に of the original light amount as a whole.

Next, the third optical system shown in FIG.
In the configuration example, between the concave mirror 15 and the user's pupil 16, the half mirror 81, the quarter-wave plate 106, and the absorption linear polarizer 107 are integrally arranged in this order. This is because, in the configuration shown in FIG. 10A, the half mirror 81, the absorption linear polarizer 101, and the 1/4 polarizer 1
02 are integrated, and the optical paths of the light emitted from the display element 11 and the reflected light are the same as those in FIG. In the configuration shown in FIG. 10C, the number of parts can be reduced, and the position of the user's pupil 16 can be closer to the half mirror 81, so that the entire apparatus can be downsized. . Further, in the configuration of FIG. 10C, a configuration in which the 波長 wavelength plate 106 and the absorption linear polarizer 107 are replaced may be adopted. In this case, the optical paths of the outgoing light and the reflected light from the display element 11 are the same as in the case of FIG.

As described above, there have conventionally been several methods for blocking the reflected light due to the illumination light of the user's face 17 or for suppressing the amount of light. by the way,
The light that has entered the half mirror 81 transmits １ ／ of the light amount, and reflects the remaining ２. In each of the optical systems shown in FIG. 10, the light emitted from the display element 11 is reflected once by the half mirror 81, then reflected by the concave mirror 15, re-enters the half mirror 81, and transmitted therethrough. And reaches the user's pupil 16. Therefore, there is a problem that the amount of light emitted from the display element 11 is reduced to １ ／ by passing through the half mirror 81 twice.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a display device in which reflected light from a user is blocked and light use efficiency for displaying an image is improved. Aim.

Another object of the present invention is to provide an enlarged image generating method in which reflected light from a user is blocked and the light use efficiency for displaying an image is improved.

[0019]

According to the present invention, there is provided a display device for displaying an enlarged image as a virtual image, wherein the image is displayed and light of the image is linearly polarized. A reflective linear polarizer arranged to reflect the light of the displayed image; and reflecting the light of the image reflected by the reflective linear polarizer and causing the reflected linear polarizer to enter the reflective linear polarizer again. A concave mirror arranged as described above, and a 波長 wavelength plate arranged between the reflective linear polarizing plate and the concave mirror.

In such a display device, linearly polarized light from an image displayed on the image display section is reflected by a reflective linear polarizer, enters a quarter-wave plate, and is transmitted therethrough. The light is converted into circularly polarized light and enters the concave mirror. The light of the image reflected by the concave mirror becomes circularly polarized light having a helical direction opposite to that of the other direction, is incident on the quarter-wave plate again, is transmitted therethrough, is converted into linearly polarized light, and is incident on the reflective linear polarizing plate. I do. Since the vibration direction of this light matches the transmission axis direction of the reflective linear polarizer, it passes through the reflective linear polarizer,
Reach the user's eyes. As a result, the light emitted from the image display unit is visually recognized by the user with almost no decrease in the amount of light in the optical path.

On the other hand, light from the user's face illuminated by the light from the image display unit or the external light enters the reflective linear polarizer, and a straight line coinciding with the transmission axis direction of the reflective linear polarizer. Only the polarized light component is transmitted and enters the quarter-wave plate. This light is converted into circularly polarized light by the quarter-wave plate, is incident on the concave mirror and is reflected, is converted into circularly-polarized light having a helical direction opposite to that, and is incident on the quarter-wave plate again. This light is converted into linearly polarized light by a quarter-wave plate and is incident on the reflective linear polarizer. However, since the vibration direction is orthogonal to the transmission axis direction of the reflective linear polarizer, the direction of the image display unit is changed. And is absorbed by the image display unit. As a result, reflected light due to the illuminated user's face is removed.

Further, according to the present invention, in an enlarged image generating method for generating an enlarged image visually recognized by a user as a virtual image, light of an image which is linearly polarized and displayed by an image display section is reflected by a reflective linear polarizing plate. The light of the image reflected by the reflective linear polarizing plate is transmitted through a 波長 wavelength plate and then reflected by a concave mirror, and the light of the image reflected by the concave mirror is reflected by the 波長 wavelength. After passing through the plate, passing through the reflective linear polarizer,
An enlarged image generation method is provided, wherein an image is formed on the pupil of the user.

In such an enlarged image generating method, the linearly polarized light from the image displayed on the image display unit is reflected by the reflective linear polarizer and enters the quarter-wave plate.
By transmitting the light, the light is converted into circularly polarized light and is incident on the concave mirror. The light of the image reflected by the concave mirror becomes circularly polarized light having a helical direction opposite to that of the other direction, is incident on the quarter-wave plate again, is transmitted therethrough, is converted into linearly polarized light, and is incident on the reflective linear polarizing plate. I do. Since the vibration direction of this light matches the transmission axis direction of the reflective linear polarizer, the light transmits through the reflective linear polarizer and reaches the user's pupil. As a result, the light emitted from the image display unit is visually recognized by the user with almost no decrease in the amount of light in the optical path.

On the other hand, the light from the user's face illuminated by the light from the image display unit or the external light is incident on the reflective linear polarizer, and a straight line coincident with the transmission axis direction of the reflective linear polarizer. Only the polarized light component is transmitted and enters the quarter-wave plate. This light is converted into circularly polarized light by the quarter-wave plate, is incident on the concave mirror and is reflected, is converted into circularly-polarized light having a helical direction opposite to that, and is incident on the quarter-wave plate again. This light is converted into linearly polarized light by a quarter-wave plate and is incident on the reflective linear polarizer. However, since the vibration direction is orthogonal to the transmission axis direction of the reflective linear polarizer, the direction of the image display unit is changed. And is absorbed by the image display unit. As a result, reflected light due to the illuminated user's face is removed.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described. FIG. 1 shows a configuration of an optical system of the display device according to the first embodiment.

In the display device 10 shown in FIG. 1, a correction lens 12 for correcting an optical path is provided in front of a display element 11 on which image information from a computer device or a video device is displayed.
A reflective linear polarizing plate 13 is provided. Display element 11
For example, a self-lighting type such as a transmissive LCD is used, and linearly polarized light is emitted using a linear polarizing plate. Further, the reflective linearly polarizing plate 13 is arranged so as to be inclined with respect to the axis of light of an image displayed on the display element 11. The reflective linearly polarizing plate 13 transmits polarized light having one vibration direction and reflects polarized light having a vibration direction orthogonal to the one direction. The reflective linear polarizer 13 is disposed so that the transmission axis direction is orthogonal to the vibration direction of the linearly polarized light from the display element 11. On the optical path where the light emitted from the display element 11 is reflected by the reflective linear polarizer 13, a 波長 wavelength plate 14 and a concave mirror 15 are arranged in order in opposition to the reflective linear polarizer 13. I have.

In the display device 10 having such a configuration,
When an image is displayed on the display element 11, the light 10 of the image is displayed.
The optical path a is corrected by the correction lens 12, enters the reflective linear polarizer 13, and is reflected. This reflected light 1
Ob is incident on the 波長 wavelength plate 14, is transmitted therethrough, is converted into circularly polarized light, and is incident on the concave mirror 15. The helical direction of this circularly polarized light is determined by the relative relationship between the transmission axis direction of the reflective linear polarizer 13 and the slow axis direction of the quarter-wave plate 14. Here, the transmitted light 1 of the 波長 wavelength plate 14
Assuming that 0c becomes the LCP, the transmitted light 10c is reflected by the concave mirror 15, and the reflected light 10d becomes the RCP and enters the quarter-wave plate 14 again. Reflected light 10d
Are transmitted through the 波長 wavelength plate 14, are converted into linearly polarized light 10 e, and are incident on the reflective linearly polarizing plate 13 again. Since the phase has changed due to reflection on the concave mirror 15, the light 10
The vibration direction of e becomes the same as the transmission axis direction of the reflective linear polarizer 13, and the light 10 e transmits through the reflective linear polarizer 13, becomes outgoing light 10 f, and reaches the pupil 16 of the user. To form an image.

On the other hand, when the user's face 17 is illuminated by the display element 11 or external light, the light 10 g reflected by the user's face 17 enters the display device 10 and is reflected by the reflective linear polarizer 13. Reach The reflective linear polarizer 13 transmits, among the polarized components of the light 10g, linearly polarized light having a vibration azimuth coinciding with the transmission axis azimuth, and reflects linearly polarized light having a vibration azimuth orthogonal to this. This reflected light 10h is absorbed by a lens barrel (not shown) below in the figure. The light 10i transmitted through the reflective linear polarizer 13 is incident on the quarter-wave plate 14, converted into RCP light 10j, and incident on the concave mirror 15. This light 10j is reflected by the concave mirror 15 and
The light is converted into the CP light 10k, and then enters the quarter-wave plate 14 again to be converted into linearly polarized light 10l. 10l of this light
Is orthogonal to the transmission axis azimuth of the reflective linear polarizer 13, and is reflected by the reflective linear polarizer 13. The reflected light 10m passes through the correction lens 12, enters the display element 11, and is absorbed.

As described above, in the display device 10, the light 10 a from the display element 11 is reflected in the direction of the concave mirror 15,
Light 10 transmitted through quarter-wave plate 14 from concave mirror 15
The function of transmitting e in the direction of the user is performed by the reflective linear polarizer 13. This function is conventionally performed by a half mirror.
With the use of the reflective linearly polarizing plate 13, the linearly polarized light 10a emitted from the display element 11 is transmitted in the optical path until reaching the user without substantially reducing the amount of light. For this reason, the light use efficiency at the time of displaying a virtual image is improved, the display by the display element 11 can be made bright without increasing the power consumption, and the power consumption can be suppressed at the same light amount. Become.

For the reflected light due to the illumination of the user's face 17, the reflective linear polarizing plate 13 and the quarter-wave plate 14 operate as circularly polarized light selecting elements, thereby providing a concave mirror. The light 10l reflected by 15 and transmitted through the quarter-wave plate 14 is reflected on the display element 11 side and does not transmit on the user side. Thereby, the reflected light is blocked, and the image quality of the displayed virtual image can be kept good.

Next, FIG. 2 shows a configuration example of a display device 10 including the optical system shown in FIG. FIG. 2A shows the display device 1.
0 shows a side view, and (b) shows a plan view. The display device 10 shown in FIG. 2 uses a transmissive liquid crystal display device using an LCD 11a and a backlight 18 as display elements. The backlight 18 has an LED (Light Emitti) inside.
ng Diode), and irradiates the LCD 11a with light from above. The LCD 11a has a structure in which, for example, a liquid crystal layer is sandwiched between an alignment film and a transparent electrode film, and a transparent plate and a polarizing plate are laminated, and an image is displayed by controlling transmission of light from the backlight 18. I do. Further, a linear polarizing plate 19 is arranged on the lower surface of the LCD 11a. After the light of the image displayed by the LCD 11a passes through the linear polarizing plate 19, the optical system until it is visually recognized by the user is the same as the optical system shown in FIG. The reflective linearly polarizing plate 13 is arranged so as to transmit the LCD 11a and reflect light transmitted through the linear polarizing plate 19. In addition, the reflection type linear polarizing plate 13 is, for example,
It is produced by multi-layer laminating and stretching two types of polymer films having different refractive indices. In addition, the 板 wavelength plate 14
Is a stretched film of, for example, polycarbonate or the like, having an optical path difference Δnd of １ ／ wavelength at a target wavelength.

When using the display device 10, the user approaches the face 17 to the opening 100 of the display device 10 as shown in FIG. By visually recognizing the enlarged virtual image displayed on the LCD 11a and reflected by the concave mirror 15, the user can feel as if he were looking at a large screen with a sense of reality, for example, 50 inches 2m away. . Further, the user may wear the display device 10 on the head and use it. In this case, the optical path from the LCD 11a to the user's pupil 16 is made as short as possible, and the overall size of the display device 10 is reduced. The opening 100 is provided with, for example, a pad. The user presses the pad against the forehead and hangs the head on the head, so that the user wears the display device 10 as if wearing glasses, and touches the lens of the glasses. Is visually recognized.

As shown in FIG. 2A, the display device 10 has a configuration in which one image displayed by the LCD 11a is visually recognized by the left and right eyes of the user. Alternatively, an independent LCD 11a may be provided.

Next, a second embodiment of the present invention will be described. FIG. 3 shows the configuration of the optical system of the display device according to the second embodiment. In the display device 20 illustrated in FIG. 3, a 波長 wavelength plate 21 is provided in front of the display element 11 on which an image is displayed.
An optical path correction lens 12 and a reflective circularly polarizing plate 22 using cholesteric liquid crystal are arranged. As the display element 11, a self-lighting type such as a transmissive LCD is used, and emitted light is linearly polarized light. The reflective circularly polarizing plate 22 is arranged so as to be inclined with respect to the axis of light of an image displayed on the display element 11. Further, light emitted from the display element 11 is reflected by the reflective circularly polarizing plate 22.
The concave mirror 15 is arranged directly opposite the reflective circularly polarizing plate 22 on the optical path reflected by the mirror.

The reflective circularly polarizing plate 22 transmits circularly polarized light in one azimuth direction and reflects polarized light in an azimuth direction orthogonal to the one. A circular polarizing plate using selective reflection by cholesteric liquid crystal is disclosed in the specification of JP-A-6-281814. In a polarizer using a cholesteric liquid crystal, a helical chiral molecule is aligned in an optically active layer made of a cholesteric material, and a portion of the irradiated light that matches the direction and pitch of the helix is reflected. The portion orthogonal to this direction is transmitted. The spiral pitch is 100
When the wavelength is changed by nm or more, the wavelength range in which selective reflection can be performed can be made the entire visible range. By using such a polarizer, a reflective circularly polarizing plate 22 having no wavelength dependence can be obtained.

The light emitted from the display element 11 is linearly polarized light, and the light of the image displayed by the display element 11 is
The light is converted by the quarter-wave plate 21 into circularly polarized light 20a. The reflective circularly polarizing plate 22 is disposed so that the transmission axis direction is orthogonal to the vibration direction of the light 20a. As a result, the light 20a transmitted through the quarter-wave plate 21 is reflected by the reflective circularly polarizing plate 22, and becomes light 20b incident on the concave mirror 15. Assuming that this light 20b is RCP, the light 20b is reflected by the concave mirror 15 and the LCP light 20c
And is incident on the reflective circularly polarizing plate 22 again. The helical direction of the light 20c is the direction of transmission through the reflective circularly polarizing plate 22, and is transmitted through the reflective circularly polarizing plate 22 to be emitted light 20d to form an image on the pupil 16 of the user.

On the other hand, when the user's face 17 is illuminated by the display element 11 or external light, the light 20e reflected by the user's face 17 enters the inside of the display device 20 and is reflected by the reflective circularly polarizing plate 22. Reach The reflective circularly polarizing plate 22 receives the light 20e.
Of the polarized light components, the LCP light is transmitted, and the RCP light is reflected. The reflected light 20f is absorbed by a lens barrel (not shown) below in the figure. The light 20g transmitted through the reflective circularly polarizing plate 22 enters the concave mirror 15. This light 20g is reflected by the concave mirror 15 and becomes RCP light 20h.
And is incident on the reflective circularly polarizing plate 22 again. Since the reflective circularly polarizing plate 22 reflects the RCP, the light 20h is reflected by the reflective circularly polarizing plate 22, and the reflected light 20i is reflected.
Is transmitted through the correction lens 12 and the quarter-wave plate 21,
The light enters the display element 11 and is absorbed.

As described above, in the display device 20, the light 20a from the display element 11 is reflected in the direction of the concave mirror 15, and
The function of transmitting the light 20c reflected by the concave mirror 15 in the direction of the user is performed by the reflective circularly polarizing plate 22. As a result, the linearly polarized light 20a emitted from the display element 11 is transmitted with almost no decrease in the amount of light in the optical path before reaching the user.
Light utilization efficiency in displaying a virtual image is improved. Also, with respect to the reflected light due to the illumination of the user's face 17, the reflective circularly polarizing plate 22 operates as a circularly polarized light selection element, so that the light 20h reflected by the concave mirror 15 is displayed on the display element. It is reflected on the 11 side and does not pass through to the user side. Thereby, the reflected light is blocked, and the image quality of the displayed virtual image can be kept good.

Next, a third embodiment of the present invention will be described. FIG. 4 shows a configuration of an optical system of a display device according to the third embodiment. FIG. 4A is a front view seen from the user side,
(B) shows a side view, respectively.

In the display device 30 shown in FIG. 4, an optical path correction lens 12 and a reflective linear polarizer 32 are arranged in front of a reflective display element 31 on which an image is displayed. As the reflection type display element 31, for example, a reflection type LCD or the like is used. In this case, an image is displayed by reflecting light incident from the front side on the reflection surface on the back side and transmitting the reflected light to the LCD. . Hereinafter, the display element 31 is a reflective LC
Description will be made assuming that D is used. In order to irradiate the display element 31 with light, two point light sources 3 corresponding to the left and right pupils 16 of the user are positioned directly opposite the display element 31.
3. A condensing lens 34 for condensing the light emitted from the point light source 33 on the pupil 16 of the user, and a linear polarizing plate 35 are sequentially arranged along the optical path from the point light source 33. Two point light sources 3
Reference numeral 3 denotes, for example, LEDs, which are arranged in parallel to a surface facing the user. The condenser lens 34 is, for example, a Fresnel lens. Further, the reflection type linear polarizing plate 32 is
Are arranged in an inclined state with respect to the axis of light according to the image displayed by. Furthermore, on the optical path where the light emitted from the display element 31 is reflected by the reflective linear polarizer 32,
The quarter-wave plate 36 and the concave mirror 15 are arranged in order in such a manner as to face the reflective linearly polarizing plate 32.

FIG. 5 shows an optical path in the display device 30. 5A shows an optical path for displaying an image, and FIG. 5B shows an optical path of reflected light. First, an optical path for displaying an image will be described with reference to FIG. In order to display an image on the display element 31, light 30a is emitted from a point light source 33, and this light 30a is condensed on the user's pupil 16 by a condenser lens 34. The light is transmitted, becomes linearly polarized light 30b, and enters the reflective linearly polarizing plate 32. The reflective linear polarizer 32 is
The transmission axis direction is arranged so as to transmit the light 30b, and the light 30c transmitted through the reflective linearly polarizing plate 32 is transmitted through the correction lens 12 and is incident on the display element 31. In the display element 31, the incident light is reflected by a reflection plate (not shown) provided on the back surface of the LCD, and is transmitted through the LCD again to display an image. In addition, the linearly polarized light is modulated by passing through the LCD, and a phase change of π / 2 is made.
The vibration direction of the light 30d emitted from and transmitted through the correction lens 12 is a direction orthogonal to the light 30c.

The light 30d of the image displayed on the display element 31 is incident on the reflective linear polarizer 32 after its optical path is corrected by the correction lens 12. As described above, since the light 30d is linearly polarized light whose vibration direction is orthogonal to the transmission axis of the reflective linearly polarizing plate 32, the light 30d is reflected by the reflective linearly polarizing plate 32. The reflected light 30e enters the quarter-wave plate 36, passes through it, is converted into circularly polarized light 30f, and enters the concave mirror 15. Here 1 /
Assuming that the light 30f transmitted through the four-wavelength plate 14 becomes an LCP, the light 30f is reflected by the concave mirror 15, and the reflected light 30g becomes an RCP and enters the quarter-wave plate 36 again. The reflected light 30g passes through the quarter-wave plate 36, is converted into linearly polarized light 30h, and is incident on the reflective linearly polarizing plate 32 again. Since the phase is changed by the reflection at the concave mirror 15, the vibration direction of the light 30h becomes the same as the transmission axis direction of the reflective linear polarizer 32, and the light 30h transmits through the reflective linear polarizer 32 and goes to the outside. Outgoing light 30i of
It reaches the user's pupil 16 and forms an image.

Next, the optical path of the reflected light is shown in FIG.
This will be described with reference to FIG. When the user's face 17 is illuminated by the light from the point light source 33 or external light, the light 30 j reflected by the user's face 17 enters the inside of the display device 30 and reaches the reflective linear polarizer 32. . The reflection-type linear polarizing plate 32 transmits, among the polarization components of the light 30j, linearly polarized light having a vibration azimuth coinciding with the transmission axis azimuth, and reflects linearly polarized light having a vibration azimuth orthogonal thereto. The reflected light 30k is absorbed by a lens barrel (not shown) below in the figure. Also,
The light 301 transmitted through the reflective linearly polarizing plate 32 enters the quarter-wave plate 36, is converted into RCP light 30 m, and enters the concave mirror 15. The light 30m is reflected by the concave mirror 15, is converted into LCP light 30n, is incident on the quarter-wave plate 36 again, and is converted into linearly polarized light 30o.
Since the vibration direction of the light 30o is orthogonal to the transmission axis direction of the reflective linear polarizer 32, the light 30o is reflected by the reflective linear polarizer 32, and the reflected light 30p is transmitted through the correction lens 12 to the display element 31. Incident and absorbed.

Here, FIG. 6 shows a point light source 33 and a condenser lens 3.
4, the positional relationship between the display element 31 and the user is conceptually shown.
FIG. 6 conceptually shows an optical path until the emitted lights from the two point light sources 33a and 33b reach the left and right pupils 16a and 16b of the user. Note that, for simplicity, the correction lens 12, the reflective linear polarizer 32, and the linear polarizer 3
The 5 and 1/4 wavelength plates 36 are omitted, and the display element 3
1 does not show folding of the optical path at the concave mirror 15. As described above, the two point light sources 33a and 33
b corresponds to the left and right pupils 16a and 16b of the user, respectively. The light emitted from each of the point light sources 33a and 33b is reflected by the display element 31 to become light for image display, and this light is further reflected by the concave mirror 15 and forms an image on the left and right pupils 16a and 16b of the user. There must be.
For this reason, in this optical system, each point light source 33a and 3
The light emitted from 3b is condensed by the condenser lens 34, so that an image is formed on the left and right pupils 16a and 16b of the user. As the condenser lens 34, for example, a Fresnel lens is used. In the Fresnel lens, the width of the lens is divided finely and the curvature is arranged on a plane, so it is thinner and lighter than a normal lens,
Since the focal length can be made shorter than the aperture, it is suitable for making the entire display device 30 smaller.

As described above, in the display device 30, the linear polarizing plate 35, the reflective linear polarizing plate 32, and the 1 /
By controlling the polarization using the four-wavelength plate 36,
The light amount is transmitted with almost no decrease, and the light use efficiency in displaying a virtual image is improved. In addition, with respect to the reflected light due to the illumination of the user's face 17, the reflective linear polarizing plate 32 and the quarter-wave plate 36 operate as circularly polarized light selecting elements, so that the concave mirror 1 is formed.
Light 3 reflected by 5 and transmitted through quarter-wave plate 36
0h is reflected on the display element 31 side and is not transmitted on the user side. Thereby, the reflected light is blocked, and the image quality of the displayed virtual image can be kept good.

In the display device 30, the reflective linear polarizing plate 32 functions as a polarizing beam splitter. However, when the degree of polarization separation is low, the display contrast of a virtual image may be adversely affected. In this case, the reflective linear polarizer 32
By disposing a linear polarizing plate on the optical path on the user side, the display contrast is improved.

Finally, a fourth embodiment of the present invention will be described. FIG. 7 shows a configuration of an optical system and an optical path of a display device according to the fourth embodiment. 7A shows the optical path of the display image, and FIG. 7B shows the optical path of the reflected light.

First, the configuration of the optical system of the display device according to the fourth embodiment will be described with reference to FIG. The display device 40 is configured to display an image using the reflective display element 31 as in the display device 30 according to the third embodiment described above. The difference from the display device 30 is
A reflective circular polarizer 41 is used in place of the reflective linear polarizer 32, and a circular polarizer 42 is disposed between the condenser lens 34 and the reflective circular polarizer 41 instead of the linear polarizer 35. That is, the quarter-wave plate 36 disposed in front of the concave mirror 15 has been removed. The reflective circularly polarizing plate 41 is
A circular polarizer using selective reflection by cholesteric liquid crystal similar to that used in the second embodiment described above is used. The helical pitch of the alignment molecules in the cholesteric liquid crystal layer is adjusted so that the reflective circularly polarizing plate 41 has a selective absorption wavelength band in the visible region. Further, as in the third embodiment, a reflective LCD or the like is used as the reflective display element 31. Hereinafter, the display element 31 will be described as using a reflective LCD.
Further, the point light source 33 is an LED or the like,
Is a Fresnel lens or the like. By using a Fresnel lens as the condenser lens 34, the installation space for this lens can be reduced.

Next, an optical path for displaying an image on the display device 40 will be described with reference to FIG. The light 40a emitted from the point light source 33 is condensed on the pupil 16 of the user by the condensing lens 34, and
2 is transmitted to form a circularly polarized light 40 b and enters the reflective circularly polarizing plate 41. The reflective circularly polarizing plate 41 is disposed so that the transmission axis direction transmits the light 40b. Here, it is assumed that the light 40b is RCP. The light 40c transmitted through the reflective circularly polarizing plate 41 is transmitted through the correction lens 12 and enters the display element 31. In the display element 31, the incident light is reflected by a not-shown reflector provided on the back of the LCD,
The image is displayed by passing through the LCD again.
In addition, due to the reflection at the display element 31, the incident light 40c is converted into an LCP and emitted.

The light 40d of the image displayed by the display element 31 is incident on the reflective linear polarizer 32 after the optical path is corrected by the correction lens 12. Since the light 40d is an LCP, the light 40d is reflected by the reflective circularly polarizing plate 41, and the reflected light 40e enters the concave mirror 15. The light 40e is reflected by the concave mirror 15, and the reflected light 40e
f is converted into RCP, re-enters the reflective circularly polarizing plate 41, passes through it, becomes outgoing light 40g, and reaches the user's pupil 16 to form an image.

Next, the optical path of the reflected light is shown in FIG.
This will be described with reference to FIG. When the user's face 17 is illuminated by the light from the point light source 33 or external light, the light 40 h reflected by the user's face 17 enters the inside of the display device 40 and reaches the reflective circularly polarizing plate 41. . Reflective circularly polarizing plate 41
Then, among the polarization components of the light 40h, the RCP is transmitted,
The LCP is reflected. The reflected light 40i is absorbed by a lens barrel (not shown) below in the figure. The transmitted light 4
0j enters the concave mirror 15. This light 40j is reflected by the concave mirror 15 and converted into LCP light 40k.
The light enters the reflective circularly polarizing plate 41 again. Light 40k is LCP
Is reflected by the reflective circularly polarizing plate 41, and the reflected light 401 passes through the correction lens 12, enters the display element 31, and is absorbed.

As described above, in the display device 40, the polarization is controlled using the circular polarizer 42 and the reflective circular polarizer 41 in the optical path from the point light source 33 to the emitted light reaching the user. As a result, light is transmitted without substantially reducing the amount of light, and the light use efficiency in displaying a virtual image is improved. Further, with respect to the reflected light due to the illumination of the user's face 17, the reflective circularly polarizing plate 41 operates as a circularly polarized light selecting element, so that the light 41k reflected by the concave mirror 15 is displayed on the display element. 31
Is reflected to the side and does not pass through to the user side. Thereby, the reflected light is blocked, and the image quality of the displayed virtual image can be kept good.

In the display device 40, the reflective circularly polarizing plate 41 functions as a polarizing beam splitter. However, when the degree of polarization separation is low, the display contrast of a virtual image may be adversely affected. In this case, by disposing the circularly polarizing plate on the optical path on the user side of the reflective circularly polarizing plate 41, the display contrast is improved.

[0054]

As described above, in the display device of the present invention, the function conventionally performed by the half mirror is performed by the reflective linear polarizer, so that the amount of light from the image display unit is reduced by the user. It is possible to prevent a drop in the optical path until it is visually recognized. Further, a quarter-wave plate is disposed between the reflective linear polarizing plate and the concave mirror to constitute a circularly polarized light selecting element, thereby removing reflected light due to illumination of the user's face. be able to.

Further, in the enlarged image generating apparatus of the present invention, the function conventionally performed by the half mirror is performed by the reflective linear polarizer, so that the user can visually recognize the amount of light from the image display unit. It can be prevented from lowering in the optical path up to. Further, a quarter-wave plate is disposed between the reflective linear polarizing plate and the concave mirror to constitute a circularly polarized light selecting element, thereby removing reflected light due to illumination of the user's face. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an optical system of a display device according to a first embodiment.

FIGS. 2A and 2B are diagrams illustrating a configuration example of a display device according to the first embodiment, wherein FIG. 2A is a side view of the display device, and FIG.

FIG. 3 is a diagram illustrating a configuration of an optical system of a display device according to a second embodiment.

FIG. 4 is a diagram illustrating a configuration of an optical system of a display device according to a third embodiment, where (a) is a front view viewed from a user side,
(B) shows a side view.

5A and 5B are diagrams illustrating an optical path in a display device according to a third embodiment, where FIG. 5A illustrates an optical path for displaying an image, and FIG.
Indicates the optical path of the reflected light.

FIG. 6 is a diagram conceptually showing a positional relationship among a point light source, a condenser lens, a display element, and a user.

FIGS. 7A and 7B are diagrams illustrating a configuration of an optical system and an optical path of a display device according to a fourth embodiment. FIG. 7A illustrates an optical path of a display image, and FIG. 7B illustrates an optical path of reflected light.

FIG. 8 is a diagram illustrating a configuration example of an optical system of a conventional display device.

FIG. 9 is a diagram showing an optical path of light from a illuminated user's face.

FIG. 10 is a diagram illustrating a configuration example of an optical system of a conventional display device using a circularly polarized light selection element, where (a) is a first configuration example,
(B) shows a second configuration example, and (c) shows a third configuration example.

[Explanation of symbols]

10 display device, 11 display element, 11a liquid crystal display panel (LCD), 12 correction lens, 13
Reflective linear polarizing plate, 14 １ ／ wavelength plate, 15 concave mirror, 16 pupil of user, 17 face of user,
18 ... backlight, 19 ... linear polarizing plate, 100 ...
…Aperture

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 520 G02F 1/1335 520 1/13363 1/13363 F-term (Reference) 2H049 BA02 BA03 BA07 BA25 BA43 BA46 BB03 BB62 BC03 BC14 BC22 2H088 EA10 EA13 HA17 HA18 HA21 HA22 HA24 HA27 HA28 MA02 MA06 2H091 FA08X FA11X FA15X FA17X FA17Z FA26X FA27X FA41X FA45X FB02 FD06 FD08 FD10 LA03 LA17 MA02 MA07 2A0

Claims (16)

[Claims] 1. A display device for visually recognizing an enlarged image as a virtual image, comprising: an image display unit for displaying an image, wherein the light of the image is linearly polarized; and an image display unit arranged to reflect the light of the displayed image. A reflective linear polarizer; a concave mirror arranged to reflect the light of the image reflected by the reflective linear polarizer and to make the light enter the reflective linear polarizer again; and the reflective linear polarizer. And a 波長 wavelength plate disposed between the concave mirror and the concave mirror. 2. The display device according to claim 1, wherein the image display unit is a transmissive liquid crystal display device that displays the image by irradiating light from the back of the liquid crystal panel. 3. A display device for visually recognizing an enlarged image as a virtual image, comprising: an image display unit for displaying an image, wherein light of the image is linearly polarized light; and a 波長 wavelength disposed on an optical path of the displayed image. A cholesteric liquid crystal layer arranged so as to reflect light of the image transmitted through the １ ／ wavelength plate and having a helical pitch of liquid crystal molecules adjusted to have a selective reflection wavelength band in a visible region. A reflective circularly polarizing plate, and a concave mirror arranged so as to reflect the light of the image reflected by the reflective circularly polarizing plate and make the light again enter the reflective circularly polarizing plate. Display device. 4. The display device according to claim 3, wherein the image display unit is a transmissive liquid crystal display device that displays the image by irradiating light from the back of the liquid crystal panel. 5. A display device for visually recognizing an enlarged image as a virtual image, comprising: two point light sources for irradiating light to right and left pupils of a user; and a linear polarizing plate disposed on an optical path of light from the point light source. An image display unit that displays an image by reflecting light from the point light source; and between the linear polarizer and the image display unit, light emitted from the point light source and transmitted through the linear polarizer. A reflective linear polarizer that is arranged to transmit and reflect the light of the image displayed by the image display unit, and reflect the light of the image reflected by the reflective linear polarizer and again A display device comprising: a concave mirror arranged so as to be incident on a reflective linear polarizer; and a quarter-wave plate arranged between the reflective circular polarizer and the concave mirror. . 6. The reflection type liquid crystal display device according to claim 5, wherein the image display section displays the image by reflecting light emitted from the point light source on a back surface of a liquid crystal panel. Display device. 7. An optical system through which light emitted from the point light source passes, wherein a condenser lens for condensing the emitted light on left and right pupils of the user is provided between the point light source and the linear polarizer. The display device according to claim 5, wherein the display device is disposed between the display devices. 8. The display device according to claim 8, wherein the condenser lens is a Fresnel lens. 9. A display device for visually recognizing an enlarged image as a virtual image, comprising: two point light sources for irradiating light to left and right pupils of a user; and a circularly polarizing plate disposed on an optical path of light from the point light source. An image display unit that displays an image by reflecting light from the point light source; and between the circularly polarizing plate and the image display unit, light emitted from the point light source and transmitted through the circularly polarizing plate. Penetrate,
A reflection-type circle using a cholesteric liquid crystal in which the pitch of the helix of liquid crystal molecules is adjusted so as to have a selective reflection wavelength band in the visible region, arranged to reflect the light of the image displayed by the image display unit. A display device, comprising: a polarizing plate; and a concave mirror arranged to reflect the light of the image reflected by the reflective circularly polarizing plate and to make the reflected light again incident on the reflective circularly polarizing plate. . 10. The reflection type liquid crystal display device according to claim 9, wherein the image display unit displays the image by reflecting light emitted from the point light source on a back surface of a liquid crystal panel. Display device. 11. An optical system through which light emitted from the point light source passes, wherein a condensing lens for condensing the emitted light on left and right pupils of the user is provided between the point light source and the circularly polarizing plate. The display device according to claim 9, wherein the display device is disposed between the display devices. 12. The display device according to claim 11, wherein the condenser lens is a Fresnel lens. 13. An enlarged image generating method for generating an enlarged image visually recognized as a virtual image by a user, wherein the light of the image, which is linearly polarized light, displayed by an image display unit is reflected by a reflective linear polarizing plate; The image light reflected by the mold linear polarizing plate is transmitted through a quarter-wave plate and then reflected by a concave mirror. The image light reflected by the concave mirror is transmitted through the quarter-wave plate. And then transmitting the reflected light through the reflective linear polarizer to form an image on the pupil of the user. 14. An enlarged image generating method for generating an enlarged image to be visually recognized as a virtual image by a user, wherein the linearly polarized image light displayed by the image display unit is transmitted through a 波長 wavelength plate. The light reflected by the reflective circularly polarizing plate using cholesteric liquid crystal is reflected on the reflective circularly polarizing plate, the light of the image reflected by the reflective circularly polarizing plate is reflected by a concave mirror and transmitted through the reflective circularly polarizing plate, and Forming an enlarged image on a pupil. 15. An enlarged image generating method for generating an enlarged image that is visually recognized by a user as a virtual image, wherein the light from two point light sources is transmitted through a linear polarizing plate, and then transmitted through a reflective linear polarizing plate. The image display unit reflects the light from the point light source transmitted through the type linear polarizing plate to display an image, and reflects the image light displayed by the image display unit on the reflective linear polarizing plate, The light of the image reflected by the reflective linear polarizing plate is transmitted through a 波長 wavelength plate and then reflected by a concave mirror. The light of the image reflected by the concave mirror is transmitted to the 波長 wavelength plate After transmitting the light, the light is transmitted through the reflective linear polarizing plate to form an image on the left and right pupils of the user. 16. An enlarged image generating method for generating an enlarged image to be visually recognized as a virtual image by a user, wherein a light from two point light sources is transmitted through a circularly polarizing plate, and then a reflection type circularly polarizing plate using a cholesteric liquid crystal. An image is displayed by reflecting the light from the point light source transmitted through the reflective circularly polarizing plate by the image display unit, and the light of the image displayed by the image display unit is reflected by the reflective circle. Reflected on a polarizing plate, the light of the image reflected by the reflective circularly polarizing plate is reflected on a concave mirror and transmitted through the reflective circularly polarizing plate to form an image on the left and right pupils of the user, An enlarged image generation method, characterized in that: