JPH08254604A - Optical element, picture display device and image pickup unit using it - Google Patents

Abstract

PURPOSE: To miniaturize a picture display device and to make it light in weight by reducing the number of components. CONSTITUTION: A light diffusing element 12 such as a diffraction grating and a lens array and a light condensing element 13 such as a single lens and a Fresnel lens are stack by an adhesive material 14 such as an epoxy resin or the like which is optically transparent, so that an optical element 11 where the light diffusing element 12 and the light condensing element 13 are integrated is manufactured. The optical element 11 is arranged on the light-emitting side of a liquid crystal display panel 5 housed at the inside of a housing part 6 so as to be opposed to the light diffusing elements 12, so that a view finder 1 is manufactured. Thus, the picture display device is inexpensively provided by reducing the number of the components and lowering the cost of the components. Also, the optical element 11 is miniaturized and is made light in weight, so that the picture display device is miniaturized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element, an image display apparatus and an image pickup apparatus using the optical element. Specifically, the present invention relates to an optical element such as a diffraction grating used in an image display device such as a liquid crystal projector, a liquid crystal viewfinder, a liquid crystal display, a liquid crystal head mounted display or an image pickup device such as a video camera.

[0002]

2. Description of the Related Art Image display devices using a liquid crystal display panel include a viewfinder of a video camera and a head mounted display. FIG. 14A shows a schematic configuration diagram in which a part of the viewfinder 51 is broken away, 52 is a backlight light source, 53 is a liquid crystal display panel, and 54 is a polarizing plate. In the viewfinder 51, a light diffusion plate 55 such as a lens array is provided on the incident side of the liquid crystal display panel 53 so that the light emitted from the backlight light source 52 is sufficiently incident on the opening area of each pixel of the liquid crystal display panel 53. The light diffusing element (optical low pass filter) such as a diffraction grating or a lens array is arranged on the emission side of the liquid crystal display panel 53 in order to reduce the roughness of the screen due to a so-called black matrix (wiring region in the liquid crystal display panel 53). A filter) 56 is arranged. Reference numeral 57 denotes a housing that houses the liquid crystal display panel 52, the backlight light source 53, and the like.
Reference numeral 8 is a cushion material for mounting the light diffusion element 56 in the housing 57.

The light emitted from the backlight light source 52 and passing through the light diffusing plate 55 is, therefore, the liquid crystal display panel 53.
After being converted into linearly polarized light by the incident side polarization plate 54, the light passes through each pixel of the liquid crystal display panel 53 and again passes through the emission side polarization plate 54. At this time, the polarizing plate 54 on the exit side is polarized by the liquid crystal layer (not shown) of the liquid crystal display panel 53.
Since only the light having the same polarization direction as the light can pass through the polarizing plate 54, the light passing through the liquid crystal display panel 53 is displayed as a moving image by controlling the polarization characteristics of each pixel. Then, the observer 60 can see the moving image displayed on the liquid crystal display panel 53 through the eyepiece lens 59.

In the head mounted display 61 shown in FIG. 14 (b), the liquid crystal display panel 53 is arranged downward in front of the observer 60, and is arranged between the light diffusing element 56 and the eyepiece lens 59. The light which has passed through the polarizing plate 54 on the emission side is reflected by the mirror 62 arranged at 1, and the traveling direction of the light is changed. In this way, the observer 60 can observe the moving image displayed on the liquid crystal display panel 53 through the eyepiece lens 59 arranged in front of the observer 60.

[0005]

However, in these viewfinders and head mounted displays, the number of constituent parts such as the light diffusing plate, the light diffusing element, and the eyepiece lens is large, and it is difficult to assemble them. In addition, since it is manufactured for each component, the component cost is high. In addition, as the size of the optical system becomes smaller, if the liquid crystal display panel is made small and a large image is to be obtained, a large magnification is required for the eyepiece lens, which makes it thick (high numerical aperture).
However, there is a problem that the image display device becomes large in size due to the requirement of the lens. In addition, the conventional optical element has a problem in that it is heavy and inconvenient to carry, especially when used in a head mounted display, and is difficult to use.

The present invention has been made in view of the drawbacks of the above conventional examples, and an object of the present invention is to reduce the number of parts of the image display device and to reduce the size and weight of the image display device, thereby providing a convenient view. An object is to provide an image display device such as a finder or a head mounted display at low cost.

[0007]

DISCLOSURE OF THE INVENTION The optical element of the present invention is characterized in that a first optical element body having a light diffusing function and a second optical element body having a light condensing function are integrated. Therefore, by using the optical element of the present invention, the optical element having the light diffusing function and the optical element having the light condensing function can be incorporated at one time and can be easily incorporated into an image display device or the like.

In the optical element of the present invention, the first optical element body and the second optical element body can be formed on the front and back sides of a single substrate. Therefore, the first optical element body and the second optical element body are not peeled off,
By integrally molding, the manufacturing process can be simplified. Further, conventionally, two constituent parts were required, but one constituent part is sufficient, so that the cost of parts can be reduced.

Further, a sheet-shaped optical element may be used for the first optical element body or the second optical element body. Since this sheet-shaped optical element is thin, the optical element can be made thinner and very light. Moreover, even if two optical element bodies are bonded together, they do not become extremely thick parts.

An image display device of the present invention is characterized by including a liquid crystal display panel for generating an image and the optical element according to claim 1. Therefore, the number of constituent parts of the image display device is reduced, and the manufacturing cost can be reduced. In addition, the structure is simple and the assembly is easy. Further, by disposing a light condensing element such as an eyepiece lens close to the liquid crystal display panel, the image display device can be downsized.

Further, the image pickup apparatus of the present invention is characterized by including an image pickup element for capturing an image and the optical element described in claim 1. Therefore, the number of components of the image pickup device is reduced, and the manufacturing cost can be reduced. In addition, the structure is simple and the assembly is easy. Further, by arranging the light condensing element such as the image pickup lens close to the image pickup element, the size of the image pickup apparatus can be reduced.

[0012]

FIG. 1 is a partially broken schematic view showing an image display device according to an embodiment of the present invention, showing a viewfinder 1 such as a video camera. This viewfinder 1 has a backlight source 2 that emits light.
And a light diffusing plate 3 such as a lens array, and a liquid crystal display panel 5 having polarizing plates 4 attached to both surfaces thereof are housed in a housing 6, and the optical element 11 of the present invention causes the light diffusing element 12 to emit light. It is arranged so as to face the polarizing plate 4 on the emitting side. FIG. 2 shows a cross-sectional view of the optical element 11. The optical element 11 is a combination of a light diffusing element 12 such as a diffraction grating or a lens array and a light condensing element 13 such as a single lens or a Fresnel lens. And is adhered by an optically transparent adhesive agent 14 such as an epoxy resin, an ultraviolet curable resin, or an adhesive resin. The light diffusing element 12 is used as an optical low pass filter, and the light condensing element 13 is used as an eyepiece lens in this case.

The light diffusing element 12 is in the form of a sheet, and as will be described later (see FIGS. 5 and 6), a transparent sheet substrate such as triacetyl cellulose (TAC), polycarbonate (PC), polyethylene terephthalate (PET) or the like. Material 1
6, or a metal mold (stamper) in which a reversal pattern 17 of an optically functional surface 18 such as a diffraction grating or a lens array is formed on a resin material 19 for a lens such as an ultraviolet curable resin applied on a sheet base material 16. It is manufactured by pressing 15. The thickness is about 0.1 mm to 0.5 mm, the optical pattern has a depth of about 0.5 μm, and the pattern cycle is about 3
It is thin, about 30 μm. For convenience of illustration, the sheet-shaped light diffusing element 12 is shown in an exaggerated manner, but the outer shape of the sheet-shaped light diffusing element 12 is, for example, 1 mm or less in thickness and several cm square to several ten cm square. It is thin.

3 (a) to 3 (f) show sectional shapes showing specific examples of the light diffusing element 12, respectively.
Reference numeral 2 denotes a diffraction grating having a sinusoidal cross section as shown in FIG. 3A, a diffraction grating having a rectangular cross section as shown in FIG. 3B, and a diffraction cross section having a triangular cross section as shown in FIG. 3C. A grid can be used. Further, as shown in FIG. 3D, a lens array in which a large number of lens bodies are discretely arranged,
Various light diffusing elements 12 such as a lens array in which a large number of lens bodies are continuously arranged as shown in (e) or a diffraction grating having a trapezoidal cross section as shown in FIG. 3 (f) can be used.

The light emitted from the backlight light source 2 is focused on each pixel of the liquid crystal display panel 5 by the light diffusion plate 3, passes through the polarizing plate 4 on the incident side, and is incident on the liquid crystal display panel 5. To do. The incident light can pass through only a certain pattern area of the liquid crystal display panel 5, and the observer 8 can observe the moving image displayed on the liquid crystal display panel 5 through the light condensing element 13 of the optical element 11.

In this viewfinder 1, since the light diffusing element 12 and the light condensing element 13 which have conventionally been composed of two parts are integrated into one part, the number of parts should be reduced. You can In addition, the light diffusion element 1
Since the light condensing element 2 and the light condensing element 13 are integrated, a mechanism for holding the light condensing element 13 is unnecessary, and the viewfinder 1
The structure is simplified and the viewfinder 1 can be easily assembled. Further, since the light diffusing element 12 and the light condensing element 13 are integrated, the optical element 11 is connected to the liquid crystal display panel 5.
The viewfinder 1 can be miniaturized by disposing the optical element 11 away from the liquid crystal display panel 5 as in the viewfinder 1, but the light condensing element 13 can be made thin. This is preferable in that the viewfinder 1 can be made lighter. Therefore, the liquid crystal display panel 5 can be downsized and an image with a large magnification can be obtained without the viewfinder 1 becoming large or heavy. In addition, the optical element 11
If is mounted away from the liquid crystal display panel 5, the distance from the liquid crystal display panel 5 to the light diffusing element 12 becomes longer, so the diffraction angle becomes smaller, and the pattern period of the light diffusing element 12 becomes larger, so that Easy to make. By incorporating the optical element 11 of the present invention in this way, the viewfinder 1 can be made compact and lightweight. Moreover, since the sheet-shaped light diffusing element 12 is used, the optical element 11
Can be made thinner and lighter, and the viewfinder 1 can be made even smaller and lighter. Although not shown, another eyepiece lens may be provided on the exit side of the optical element 11. Also in this case, the eyepiece lens can be thin.

FIG. 4 shows an optical element 11 which is another embodiment of the present invention. The optical condensing element 1 is used as the optical element 11.
A sheet-shaped Fresnel lens 3 is used.
The Fresnel lens can be made much thinner than the single lens, and the viewfinder 1 can be made even lighter. Also,
Since the sheet-shaped light diffusing element 12 is used as the light diffusing element 12, the size and weight can be further reduced.

The optical element 11 can be manufactured, for example, as shown in FIG. FIG. 5 shows a manufacturing method by a thermal transfer method. First, the mold 15 on which the inverted pattern 17 of the optically functional surface 18 of the light diffusing element 12 is formed is preheated (FIG. 5A). ), Thickness 0.1 mm to 0.5 m
The sheet-shaped light diffusing element 1 is formed by pressing the heated mold 15 against the sheet base material 16 of about m to transfer the reversal pattern 17.
2 is produced (FIG. 5B). Next, similarly, a sheet-shaped light condensing element 13 is manufactured using the mold 15 in which the reverse pattern 17 of the light condensing element 13 is formed (FIG. 5C).
(D)). The sheet-shaped light diffusing element 1 thus manufactured
2 and the sheet-shaped light condensing element 13 are adhered to each other with the optically transparent adhesive 14 to obtain the optical element 11 (FIG. 5E).

The so-called 2P method (Pho
to polymerization-method). First, a lens resin material 19 such as an ultraviolet curable resin is applied on the sheet base material 16 (FIG. 6A), and then a gold pattern on which the reverse pattern 17 of the optically functional surface 18 of the light diffusing element 12 is formed. The mold 15 is pressed and ultraviolet rays are emitted from the light source 20 on the lower surface of the sheet base material 16 to cure the resin material 19 for the lens (FIG. 6B), and the sheet-shaped light diffusing element 12 is manufactured (FIG. 6). (C)). Next, similarly, the light condensing element 13
The sheet-shaped light condensing element 13 is manufactured using the mold 15 on which the reverse pattern 17 of FIG.
(F)). The sheet-shaped light diffusing element 1 thus manufactured
The optical element 11 can be obtained by adhering 2 and the light condensing element 13 with the adhesive 14 (FIG. 6 (g)).

The optical element 11 shown in FIG. 7 is formed by integrally forming a sheet-shaped light diffusion element 12 and a sheet-shaped light condensing element 13. The optical element 11 can be manufactured, for example, as shown in FIG. The mold 15 on which the reverse pattern 17 of the optically functional surface 18 of the light diffusing element 12 is formed in advance is heated (FIG. 8A), and pressed against the sheet base material 16 to form the optically functional surface 18. (FIG. 8B). Next, the sheet base material 16 is inverted, and the mold 1 in which the reverse pattern 17 of the optically functional surface 18 of the preheated light condensing element 13 is formed on the back surface side of the sheet base material 16.
5 is pressed (FIG. 8C), the optical functional surface 18 is formed, and the optical element 11 can be manufactured (FIG. 8D).

Further, as shown in FIG. 9, a lens resin material 19 is applied on the sheet base material 16 to form the optical functional surface 18 of the light diffusing element 12 by the 2P method (FIGS. 9A to 9A).
(C)) After that, the sheet base material 16 is turned over, the resin material 19 for lenses is applied to the back surface side of the sheet base material 16, and the optical functional surface 18 of the light condensing element 13 is formed by the 2P method. The element 11 can also be manufactured (FIG. 9 (d)-
(F)).

By integrally molding in this way, the manufacturing process can be simplified and the cost of the optical element 11 can be reduced. Further, the light diffusing element 12 and the light condensing element 13 are not easily peeled off, and the mechanical strength can be improved. In the above examples, the case of using a sheet-shaped optical element has been described, but it goes without saying that it can also be applied to a conventional optical element body manufactured by an injection molding method or the like. The optical functional surfaces 18 may be formed on both surfaces by integral molding.

FIG. 10A shows a head mounted display 2 which is another example of the image display device according to the present invention.
1 is a schematic perspective view showing the head mounted display 21 in which two sets of liquid crystal display units 23 shown in FIG. 10B are housed in a case 22 having a goggle shape, for example. The two sets of liquid crystal display units 23 have a constant convergence angle (angle of the eye) so that the virtual image can be set in an adjusted resting position (a viewpoint position that a person may be gazing in the dark).
Is provided in the case 22 so as to provide The liquid crystal display unit 23 is configured such that the backlight light source 2 and the liquid crystal display panel 5 having the polarizing plates 4 attached to both surfaces are housed in the housing 6, and the liquid crystal display unit 23 is provided between the mirror 24 and the observer 8. Light condensing element 13 and light diffusing element 12 which are eyepieces
The optical element 11 of the present invention is formed. The moving direction of the moving image displayed on the liquid crystal display panel 5 is changed by the mirror 24 toward the observer 8, and the optical element 11
Observed through. Then, when the switch of the backlight light source 2 is turned on, a moving image is displayed on the liquid crystal display panel 5, and the moving images independently captured by the left eye and the right eye are combined into one moving image by the human fusion effect. Can be observed as At this time, if the same moving image is displayed on the two sets of liquid crystal display units 23, the observer 8 can observe a two-dimensional moving image. Further, when a moving image with parallax is displayed on the two sets of liquid crystal display units 23, the observer 8 can observe a three-dimensional moving image. Also,
It is also possible to use a pair of liquid crystal display units 23, for example, to capture a moving image projected on the liquid crystal display unit 23 for the left eye and the external image for the right eye with the naked eye.
This head mounted display can also be used as a simulation device for driving training, a game device for virtual reality, and the like.

In this head mounted display 21, since the optical element 11 is light, it can be made light as a whole. Therefore, it is convenient to carry, has less weight, and less fatigue during use. In addition, the optical element 11 is connected to the liquid crystal display 5
The head mounted display 21 can be miniaturized by disposing the head mounted display 21 close to the head mounted display 21.

FIG. 11 is a schematic configuration diagram of a liquid crystal projector 31 which is another example of the image display device according to the present invention.
2 and a liquid crystal display panel 5 sandwiched between two polarizing plates 4,
It comprises a light condensing element 13 which is a projection lens and an optical element 11 of the present invention comprising a light diffusing element 12. Then, as shown in FIG. 11, the backlight light source 32 is turned on so that the light from the backlight light source 32 is emitted from the liquid crystal display panel 5.
When the liquid crystal display panel 5 is illuminated, moving images of three colors are displayed on the liquid crystal display panel 5 corresponding to the red, blue, and green pixels of the liquid crystal display panel 5. In this way, the moving images of the three colors displayed on the liquid crystal display panel 5 are successfully superposed by the light diffusing element 12 of the optical element 11, and the superposed moving images are enlarged by the light condensing element 13 to produce a color moving image. It is projected on a screen (not shown).

Further, FIG. 12 is a schematic configuration diagram of a liquid crystal projector 31 which is still another example of the image display device according to the present invention, and includes three liquid crystal display panels 5a and 5a.
b and 5c are provided, and three liquid crystal display panels 5 are provided.
An optical element 11 including a light diffusing element 12 and a light converging element 13 which is a collimating lens is arranged on the exit side of a, 5b, and 5c. In the liquid crystal projector 31, the light emitted from the backlight light source 32 and transmitted through the UV filter 33 is first separated into, for example, only the green light 36a by the dichroic mirror 34a. The separated green light 36a is incident on the liquid crystal display panel 5a after the light traveling direction is changed by the reflection mirror 35, and a green moving image is generated. The remaining light is separated into red light 36b and blue light 36c by the dichroic mirror 34b. The separated red light 36b is incident on the liquid crystal display panel 5b and produces a red moving image. Further, the blue light 36c is incident on the liquid crystal display panel 5c to generate a blue moving image. In this way, the green moving image displayed on the liquid crystal display panel 5a is transmitted through the dichroic mirror 34c, and is transmitted to the dichroic mirror 34.
It is superimposed on the red moving image reflected by c. In addition, the blue moving image displayed on the liquid crystal display panel 5c is superposed on the green and red moving images reflected by the dichroic mirror 34d after passing through the dichroic mirror 35 whose light traveling direction is changed by the reflection mirror 35. To be The moving image thus overlapped is projected by a projection lens 37 on a screen (not shown) as a moving image in color.

FIG. 13 is a schematic block diagram showing an image pickup device 41 according to the present invention. The image pickup device 41 is a CCD
It is composed of an image pickup device 42 such as (Charge Coupled Device) and the optical device 11 of the present invention. Optical element 11
Is composed of a light condensing element 13 which is an image pickup lens and a light diffusing element 12, and an optical functional surface 18 of the light diffusing element 12 is provided facing the image pickup element 42. The image incident from the outside is condensed by the light condensing element 13, then passes through the light diffusing element 12, enters the imaging element 42, and is converted into an electric signal. Conventionally, moire may occur in an image obtained depending on the arrangement period of each pixel of the image pickup element 42, but by disposing the light diffusing element 12 so as to face the incident surface of the image pickup element 42, the moire is reduced. Occurrence can be suppressed. By using the optical element 11 of the present invention also in the image pickup device 41, the number of constituent parts of the image pickup device 41 is reduced and the manufacturing cost is reduced. In addition, the imaging device 4
The assembly of 1 becomes easy. Moreover, if the optical element 11 is disposed close to the image pickup element 42, the image pickup device 41 can be easily downsized. It can also be made lighter.

[0028]

According to the optical element of the present invention, since two optical elements are required to be one optical element, it is possible to reduce the number of parts of the image display device or the image pickup device and reduce the parts cost. Further, by forming the first optical element body and the second optical element body on the front and back sides of one substrate, the component cost is further reduced, and the two optical element bodies are not separated. Further, by using a sheet-shaped optical element, it is possible to make the optical element even thinner and lighter.

By using the optical element of the present invention,
A compact and lightweight image display device and image pickup device can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a partially broken schematic diagram showing a view finder that is an image display device according to the present invention.

FIG. 2 is a cross-sectional view showing an optical element that is an embodiment of the present invention.

3 (a) to 3 (f) are diagrams showing a cross-sectional shape of a light diffusing element used for the optical element of the above.

FIG. 4 is a cross-sectional view showing an optical element that is another embodiment of the present invention.

5 (a) to 5 (e) are explanatory views showing an example of a method of manufacturing the optical element of the same.

6 (a) to 6 (g) are explanatory views showing another example of the method for manufacturing an optical element of the same.

FIG. 7 is a cross-sectional view of an optical element that is still another embodiment of the present invention.

8A to 8D are explanatory views showing an example of a method for manufacturing the optical element of the same.

9A to 9F are explanatory views showing another example of the method for manufacturing an optical element of the same.

FIG. 10A is a schematic perspective view showing a head mounted display which is another image display device according to the present invention;
(B) is the outline block diagram.

FIG. 11 is a schematic configuration diagram of a liquid crystal projector which is still another image display device according to the present invention.

FIG. 12 is a schematic configuration diagram of a liquid crystal projector which is still another image display device according to the present invention.

FIG. 13 is a schematic configuration diagram of an image pickup apparatus according to the present invention.

FIG. 14A is a partially broken schematic view showing a viewfinder which is an image display device of a conventional example, and FIG. 14B is a schematic view showing a head mounted display which is an image display device of another conventional example. Is.

[Explanation of symbols]

 1 Viewfinder 5 Liquid crystal display panel 11 Optical element 12 Light diffusing element (optical low-pass filter) 13 Light condensing element 21 Head mounted display 23 Liquid crystal display unit 31 Liquid crystal projector 41 Image sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Kurahashi 10 Ouron Co., Ltd. 10 Hanazono Dodocho, Ukyo-ku, Kyoto City, Kyoto Prefecture

Claims (5)

[Claims] 1. An optical element characterized by integrating a first optical element body having a light diffusing function and a second optical element body having a light condensing function. 2. The optical element according to claim 1, wherein the first optical element main body and the second optical element main body are formed on the front and back of one substrate. 3. The first optical element body or the second optical element body
The optical element according to claim 1, wherein at least one of the optical element bodies is a sheet-shaped optical element. 4. An image display device comprising a liquid crystal display panel for generating an image, and the optical element according to claim 1. 5. An image pickup apparatus comprising: an image pickup element for capturing an image; and the optical element according to claim 1.