JP2002182576A - Optical parts and image display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permanently bring both of incident and exit microlens arrays into tight contact with each other by lessening the deformation in molding of both lens arrays and lessening the deformation under ambient temperature and humidity conditions. SOLUTION: The light from a back light (2) is modulated by transmission type liquid crystal display elements (1a and 1b) to form display images. These display images are macroprojected to a back projection type screen by optical parts having transparent plates (7a and 7b), imagery means (5a and 5b) having the incident side and exit side microlens arrays and enlarging means (6a and 6b). The enlarging means (6a and 6b)are composed of concave Fresnel lenses and the imagery means (5a and 5b) are sandwiched by the transparent plates (7a and 7b) and the enlarging means (6a and 6b). The circumferences of the transparent plates (7a and 7b) and the enlarging means (6a and 6b) are fixed or half fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention modulates light from a light source by a light modulating means such as a liquid crystal display element to form a display image, and enlarges and projects this display image on a screen to display the image. The present invention relates to an image display device and an optical component used for magnifying and projecting the display image in the image display device.

[0002]

2. Description of the Related Art In recent years, with the rapid progress of computers, the resolution of image display devices has been dramatically improved. In addition, the display screen has been increasing in size accordingly.

The image display device of the cathode ray tube type which has been used for a long time has a good resolution, but the weight and the weight are proportionally increased.
Power consumption has increased, and it has become more expensive. In addition, since there is a problem that the depth and the weight increase when the screen is enlarged, there is naturally a limit in increasing the resolution and the screen.

Image display devices using liquid crystal display elements have undergone remarkable technological innovation in terms of resolution, and high resolutions are constantly being promoted in accordance with market needs. However, most of them are made by semiconductor processes. No rapid progress has been made in terms of larger screens.

Therefore, various attempts have been made to enlarge the screen of an image display device using a liquid crystal display element. Among them, the most practical application is to use a small liquid crystal display element as a light modulation means for modulating light from a light source to form a display image, and enlarge this display image with a projection lens. This is the method of projection. However, this method has a problem that a long projection distance is required and the thinness of the device, which is a feature of the liquid crystal display device, is impaired.

In the above-mentioned projection type image display device, a liquid crystal display element (liquid crystal panel) as a light modulating means is provided.
It has been proposed to arrange a plurality of adjacent or close panels and enlarge and project the display image of each of these liquid crystal panels to further increase the size of the screen. However, in this case, there is a problem that a seam between the liquid crystal panels appears in the image and the image quality is impaired. Several methods have been proposed for seamlessly connecting the liquid crystal panels. For example, Japanese Patent Application Laid-Open No. Hei 5-188340 discloses a technique in which a liquid crystal panel is provided with an image forming means and a magnifying means for a display image, and magnified and projected by an amount to fill a joint between adjacent liquid crystal panels. In this conventional example,
The smaller the magnification, the easier it is to reduce the thickness.

Hereinafter, a conventional image display device will be described with reference to FIGS. FIG. 17 is a plan view of an image display device in which a joint of a conventional liquid crystal panel is filled, and FIG.
FIG. 7 is a sectional view taken along line A-A1 of FIG. 17 and 18, 5
1a and 51b are transmissive liquid crystal display elements, 52 is a backlight for illuminating the liquid crystal display element, 53 is a cathode ray tube constituting the backlight, 54 is means for narrowing the divergence angle of the output light of the backlight, ie, divergence Angle control means, 55a, 55
b denotes an image forming means for projecting a display image (not shown) on the liquid crystal display elements 51a and 51b at an erect equal magnification, and 56a and 56b depict a real image projected at an erect equal magnification by the imaging means 55a and 55b. Means for enlarging, 57 is a rear projection screen,
Reference numeral 58 denotes a housing for housing these components inside.

Next, the operation of each component will be described. The backlight 52 includes a cathode ray tube 5 as a component thereof.
3, the transmission type liquid crystal display elements 51a, 51b
To illuminate. However, the transmissive liquid crystal display elements 51a, 51
1b has a viewing angle characteristic, and has a problem that the contrast is inverted with respect to a light beam that passes obliquely beyond a predetermined angle. Therefore, a divergence angle control means 54 for narrowing the divergence angle of the output light of the backlight is provided between the backlight 52 and the transmissive liquid crystal display elements 51a and 51b in order to cut off the extra rays emitted from the backlight 52. . The divergence angle control means 54 for narrowing the divergence angle of the output light of the backlight includes:
There is a means for narrowing the angle of light with respect to the incident angle within a certain angle range and returning the light at an incident angle exceeding this angle range to the original. In addition, Fujitsu Technical Report (FUJITS
U. 47, 4, (07, 1996), p355)
This is achieved by arranging conical transparent light guides. Thereby, the transmission type liquid crystal display elements 51a, 51b
The display image displayed above has a predetermined divergence angle. The liquid crystal display elements 51a, 51b are formed by image forming means 55a, 55b having an image taking angle larger than the divergence angle.
The display image displayed above is projected at the same erect magnification. The image forming means 55a and 55b are described in, for example,
No. 7 discloses this. In this publication, a rod lens array is realized by arranging a large number of two rod lenses joined in the length direction thereof in parallel. The display images projected by the imaging units 55a and 55b are enlarged by the enlarging units 56a and 56b and formed on the rear projection screen 57. Expanding means 56a,
As the 56b, for example, a concave Fresnel lens disclosed in JP-A-9-96704 can be used.

By arranging a plurality of projection units as described above and arranging each projection image on the rear projection screen 57 without any break, a high-resolution large-screen image can be obtained.

[0010]

However, in the prior art described above, the rod lens arrays are used for the imaging means 55a and 55b. Means 55
a and 55b are not only expensive but also unsuitable for mass production.

If a pair of microlens arrays disclosed in, for example, JP-A-9-274177 are used as the image forming means 55a and 55b, the microlens arrays can be easily mass-produced by molding. Can solve this problem. However, a pair of two microlens arrays are aligned with the optical axes of the microlenses formed on the respective input / output surfaces,
In addition, it is difficult to align the optical axes of the microlenses formed on both surfaces (incident surface and exit surface), and it is extremely difficult to manufacture. In particular, in the case of large-sized microlens arrays, it is necessary to keep a pair of microlens arrays in close contact on the entire surface, but thin large-sized molded products are easily deformed under the surrounding temperature and humidity conditions, so they remain constant as they are There is a problem that it can not be closely adhered.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to provide an optical component including an image forming means for reducing deformation due to a change in ambient temperature and humidity, and to use the optical component. To provide an image display device.

It is another object of the present invention to provide an image forming means for correcting deformation due to molding, an optical component including the image forming means, and an image display device using the same.

[0014]

In order to achieve the above object, according to the present invention, an incident side microlens array and an exit side microlens array are used as an image forming means of an optical component used in an image display device. The incident-side and exit-side microlens arrays are sandwiched between the first transparent plate and the second transparent plate, and the ends of the entrance-side and exit-side microlens arrays and the first and second transparent plates are fixed. Alternatively, the optical component is configured to be semi-fixed.

The edges of the microlens arrays on the entrance side and the exit side are adhered or adhered to each other with an adhesive (heat-melt type film adhesive, photocurable adhesive, etc.) or the like (ultrasonic welding, etc.). May be. Further, the second transparent plate may be used as a magnifying means, and a concave Fresnel lens is preferably used as the magnifying means. When the concave Fresnel lens has a flat surface on one side and a Fresnel surface on the other side, the concave Fresnel lens is arranged such that the Fresnel surface contacts the emission-side microlens array. Further, when the concave Fresnel lens has a flat surface on one side and a Fresnel surface on the other side, a flat portion is formed at the top of the Fresnel, and black printing for light shielding may be performed on the flat portion. Good. In addition, a U-shaped fitting is provided,
An end of the optical component is inserted into a gap between the U-shaped fixture, and the optical component is tightened at both ends of the U-shaped fixture, and the optical component is semi-fixed with the fixture.
Further, the incident side microlens array and the emission side microlens array constituting the optical component, and the ends of the first and second transparent plates may be fixed with an adhesive or an adhesive tape. The first and second transparent plates may have the same thickness, and the first and second transparent plates may be made of the same material.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the following description of the embodiment, an example in which a transmissive liquid crystal display element is used as a light modulation unit will be described.However, light from a light source is reflected for each pixel (the reflection angle of light for each pixel, Or a reflective device that forms an image by controlling the amount of reflection)
For example, a reflective liquid crystal display device or multiple micro
A micromirror device provided with a mirror may be used.

FIG. 1 is a plan view showing an embodiment of the image display device according to the present invention, and FIG. 2 is a longitudinal sectional view of the image display device shown in FIG. In the image display device shown in this figure, the liquid crystal panel can be connected and projected without a joint. Also, in FIGS. 1 and 2, the liquid crystal display
Although the case of four-plane connection using sheets is shown as an example,
The present invention can be realized regardless of how many planes are connected both vertically and horizontally.

1 and 2, reference numerals 1a and 1b denote transmissive liquid crystal display elements as light modulating means, 2 denotes a backlight as a light source for emitting light for illuminating the liquid crystal display elements 1a and 1b, 3 is a cathode tube constituting the backlight 2,
Reference numeral 4 denotes means for reducing the divergence angle of the output light of the backlight provided between the cathode tube 3 and the liquid crystal display elements 1a and 1b, that is, divergence angle control means. 5a and 5b are liquid crystal display elements 1a,
Imaging means for projecting a display image (not shown) on 1b at the same magnification as an erect image, and is configured by superimposing an incident-side microlens array and an exit-side microlens array. , 6a and 6b are enlarging means for enlarging the real image projected at the same magnification by the imaging means 5a and 5b, 7a and 7b are transparent transparent plates, 8 is a rear projection screen, 9 is a partition plate,
Reference numeral 10 denotes a housing for housing these components inside.

Next, the operation of each component will be described. The backlight 2 illuminates the transmission type liquid crystal display elements 1a and 1b by the light emission of the cathode tube 3 which is a component thereof. The transmissive liquid crystal display elements 1a and 1b transmit light from the backlight 2 and modulate the transmitted light (passing through the inside) based on an input image signal to form a display image. The transmissive liquid crystal display elements 1a and 1b have visual characteristics, and the contrast is inverted with respect to a light beam that passes obliquely beyond a predetermined angle. Therefore, in order to cut off extra rays emitted from the backlight 2, divergence angle control means 4 for narrowing the divergence angle of the output light of the backlight is provided between the backlight 2 and the transmissive liquid crystal display elements 1a and 1b. As the divergence angle control means 4 for narrowing the divergence angle of the output light of the backlight 2, for example, a thin elastic film having fine prisms formed on one side as disclosed in Japanese Patent Application Laid-Open No. 60-70601 may be used. It is possible to use two films, which are stacked so that the prisms of the two films are orthogonal to each other. By using this divergence angle control means, the divergence angle of the output light of the backlight can be set to about ± 30 °.

The display images displayed on the transmissive liquid crystal display elements 1a and 1b are projected on the rear projection screen 7 at the same magnification by the imaging means 5a and 5b. The display images projected by the image forming means 5a and 5b are
The image is enlarged by a and 6b and is imaged on the rear projection screen 7. In the present embodiment, the enlarging means 6a, 6b
Use a concave Fresnel lens. Imaging means 5a, 5
b, the configurations of the transparent plates 7a and 7b and the enlarging means 6a and 6b will be described later in detail. In the embodiment of the present invention, the images formed on the rear projection screen 7 do not overlap each other. For this reason, the partition plate 9 is provided so that no overlapping portion is formed due to an error caused by assembly accuracy or a change with time.

A plurality of projection units as described above,
By arranging the projection images on the rear projection screen 7 without any breaks, a high-resolution large-screen image can be obtained.

Next, the configuration of the image forming means 5a and 5b according to the present invention will be described with reference to FIGS. FIG. 3 is a side view showing an embodiment of the image forming means according to the present invention.
In the figure, 5 is an image forming means, 11 is an incident side micro lens array constituting the image forming means 5, and 12 is an output side micro lens array. The optical axis of each lens constituting the incident side microlens array 11 and the optical axis of each lens constituting the exit side microlens array 12 correspond one-to-one and coincide with each other.

FIG. 4 is a perspective view of the imaging means 5 as viewed from the left side of FIG. In the figure, the imaging means 5 comprises an incident side microlens array 11 and an exit side microlens array 12, but in the figure, the incident side microlens array 1 is shown.
One side is visible. In the figure, reference numeral 13 denotes an edge of the incident side microlens array 11.

In FIG. 3, the arrow A indicates the liquid crystal display element 1.
The image displayed above (not shown), arrow B, is an image projected on the rear projection screen 7 at the same size as the erect image.
Now, focusing on the lens r of the incident side microlens array 11, light emitted from the upper end portion p of the image A follows a path shown by a solid line in FIG. Similarly, the light emitted from the lower end q follows the path shown by the broken line in the figure and reaches the lower end v of the image B.

The micro lens array 11 described above,
12 is usually made by injection molding, but its thickness is extremely thin with respect to its external dimensions. For example, for a liquid crystal display element 1 having an aspect ratio of 4: 3 and a diagonal of 14.1 inches, the distance between the liquid crystal display element 1 and the incident side microlens array 11 is 30 m.
m, and the light take-in angle is ± 12 °, according to the design of the present inventors, the outer dimensions of the microlens arrays 11 and 12 are 15.3 inches (diagonal dimensions of an aspect ratio of 4: 3) and the plate thickness (lens portion). (Not including the amount of sag) was 1.6 mm.

In such a thin large-sized molded product, warping deformation is a problem. Hereinafter, the mechanism of the warpage of a thin large molded product will be described with reference to FIGS.

FIG. 5 is a cross-sectional view showing a state in which a mold for manufacturing an imaging element is filled with a resin, and FIG. 6 is a cross-sectional view showing a state in which the resin is shrunk and deformed in the mold.

In FIGS. 5 and 6, reference numeral 15 denotes a movable mold.
16 is a fixed mold, 17a is an upper cavity, 17b is a lower cavity, 19 is a spool for injecting resin, 20a
Is an upper runner, 20b is a lower runner, 21a is a resin material filled in the upper cavity 17a, and 21b is a resin material filled in the lower cavity 17b. The resin material is injected from the injection port 23, and passes through the spool 19, the upper runner 20a, and the lower runner 20b.
And the upper cavity 17a and the lower cavity 17b formed by the fixed mold 16 are filled. FIG. 5 shows a state immediately after the filling, and the filled resin material is in the cavity 17.
a and 17b are filled without gaps. FIG. 6 shows a state in which the resin is cooled in the mold, and the filled resin material shrinks and deforms in the cavities 17a and 17b to cause mold separation. The mold separation in the mold appears as warpage of the molded product.

Therefore, the micro lens array 1 is
Similarly, when the molds 1 and 12 are formed, mold release occurs, and warpage deformation occurs. Also, the micro lens array 1 to be formed
In the cases 1 and 12, the entrance surface side and the exit surface side are symmetrical, and when the movable mold 15 and the fixed mold 16 are exactly the same, it is not known which side is separated. If the mold release occurs in the opposite direction, the warpage will be reversed. Under this condition, the warpage of the molded product cannot be controlled.

As a method of controlling the warpage of a molded product, it is common practice to provide a temperature difference between the movable mold 15 and the fixed mold 16. However, this method changes the amount of shrinkage on the incident surface side and the outgoing surface side, and is adopted in the microlens arrays 11 and 12 because the optical axes of the microlenses on the incident surface side and the outgoing surface side are shifted in the peripheral portion. Can not. The image forming means 5a and 5b according to the present invention have solved the problem by adopting the following configuration.

First, the image forming means 5a and 5b of the present invention will be described. FIG. 7 is a plan view showing an embodiment of the image forming means according to the present invention, and FIG.
It is C1 longitudinal cross-sectional view. In FIG. 7, 5 is an image forming means, 1
Reference numeral 1 denotes an incident side microlens array constituting the image forming means 5, 12 denotes an exit side microlens array, 13 denotes an edge of the entrance side microlens array 11 and the exit side microlens array 12, and 14 denotes an incident side microlens array 11. And the exit side microlens array 12 are adhered at the edge 13 thereof.

The adhesive 14 needs to be solidified in a state where the axes of the lenses constituting the entrance side microlens array 11 and the exit side microlens array 12 are aligned. That is, it does not function as an adhesive when aligning the entrance-side microlens array 11 and the exit-side microlens array 12 (aligning the optical axes of the microlenses formed in each microlens array). It is necessary to function as an adhesive by stimulus from the outside. The following materials have been put to practical use as adhesives for this purpose.

(1) Heat-melt type film adhesive This is an adhesive which is solid at room temperature and becomes liquid when heated. Even if the present adhesive is sandwiched between adherends, it is a sheet at room temperature. The objects to be bonded are free from each other because they are solid and have no adhesive action. Hereinafter, the usage of the present invention will be described by taking the present invention as an example.

Edge 1 of incident side microlens array 11
The adhesive 14 is temporarily fixed to 3, and then the emission-side microlens array 12 is placed and aligned, and then the adhesive 14 is heated and melted from outside through the edge 13. After complete melting,
Bonding is completed by cooling and solidifying. At this time, needless to say, the adhesive 14 having a lower melting point than the incidence-side microlens array 11 and the emission-side microlens array 12 is selected.

(2) Photo-curable adhesive This is an adhesive which is liquid at ordinary temperature and becomes solid when irradiated with ultraviolet rays. Even if the present adhesive is sandwiched between adherends, it is liquid at ordinary temperature. Since there is no adhesive action, the adherends are free from each other. Hereinafter, the usage of the present invention will be described by taking the present invention as an example.

Edge 1 of incident-side microlens array 11
A liquid adhesive 14 is applied to 3, and then the light-emission-side microlens array 12 is placed and aligned, and then the adhesive 14 is solidified by irradiating ultraviolet light from outside through the edge 13. This completes the bonding. At this time, the incident side micro lens array 11 and the exit side micro lens array 1
Needless to say, No. 2 selects a material through which ultraviolet rays pass.

(3) Ultrasonic welding Although this is not an adhesive, the present invention can be implemented by using this. In ultrasonic welding, a projection is provided on the bonding surface of the object to be bonded, the bonding surface of the object to be bonded is sandwiched between the projections, ultrasonic vibration is applied from the outside by an ultrasonic vibrator, and the projection is melted by the energy. It is a technique of bonding. Hereinafter, the usage of the present invention will be described by taking the present invention as an example.

Edge 1 of incident-side microlens array 11
3 is provided with a projection (not shown), and then the emission-side microlens array 12 is placed and aligned.
3, vibration energy is applied to the projections to melt and adhere the projections.

The imaging means 5 composed of the incident-side microlens array 11 and the exit-side microlens array 12 adhered to each other at the edge described above has the following features.

The effects of the imaging means 5 according to the present invention will be described with reference to FIGS. FIG. 9 is a longitudinal sectional view of the image forming means 5 when the present invention is not implemented, and FIG. 10 is a longitudinal sectional view of the image forming means 5 when the present invention is implemented. 9 and 10, the same numbers as those in FIG. 8 represent the same parts.

FIG. 9 shows the incident side micro lens array 11.
4 schematically illustrates a state where the incident side microlens array 11 is heated in a state where the output side microlens array 12 is not bonded with the edge 13. As is apparent from the figure, the heated incident-side microlens array 11 is linearly expanded, and the lenses of the incident-side microlens array 11 and the exit-side microlens array 12 are misaligned in the peripheral portion.

The lens pitch of the micro lens array is set to 7
If it is 50 μm, the allowable value of the axis deviation is 50 μm.
The linear expansion coefficient of the microlens array material is 7E-5cm
/Cm.degree. C., the allowable value of the temperature difference of a 15.3 inch (diagonal dimension of an aspect ratio of 4: 3) microlens array is 4.8.degree. C., which poses a practical problem.

FIG. 10 schematically shows a state in which the incident side microlens array 11 is heated with the incident side microlens array 11 and the exit side microlens array 12 adhered by the edge 13 by implementing the present invention. Is represented in As is clear from the figure, the heated incident-side microlens array 11 linearly expands and warps toward the exit-side microlens array 12. This is because the two microlens arrays are bonded by the edge 13 and warped without shifting as shown in FIG. Even if such a warp occurs, the axes of the lenses of the incident-side microlens array 11 and the exit-side microlens array 12 are only tilted and do not shift. Although it is easy to understand in the figure, it is represented as a large warp,
For example, even if there is a temperature difference of 10.degree. C., a 15.3 inch microlens array warps with a radius of curvature of 2000 mm or more, and there is no practical problem.

Next, an optical component including the image forming means according to the present invention will be described. FIGS. 11 and 12 are side views showing an embodiment of an optical component including an imaging unit according to the present invention.
FIG. 11 shows a state before assembling, and FIG. 12 shows a state after assembling.

In the figure, 5 is an image forming means, 11 is an incident side micro lens array constituting the image forming means 5, 12 is an output side micro lens array, and 14 is an incident side micro lens array 11 and an output side micro lens. Array 1
2 is an adhesive for bonding, 6 is an enlarging means composed of a concave Fresnel lens, 7 is a transparent transparent plate, and 22 is a U-shaped fixture.

The imaging means 5 composed of the incident-side microlens array 11 and the emission-side microlens array 12, which are thin large-sized molded products, is composed of a transparent plate 7 and an enlarging means 6 composed of concave Fresnel lenses. Pinch. As shown in FIG. 11, the transparent transparent plate 7 and the enlarging means 6 are flat plates without warpage deformation. Therefore, as shown in FIG. When the two sides of the U-shaped fixture 22 are tightened and semi-fixed, the imaging means 5 is sandwiched from both sides.
Incident-side microlens array 11 constituting imaging means 5
And the exit side microlens array 12 are in close contact with each other regardless of the initial warping direction.

In this embodiment, the transparent transparent plate 7
The image forming means 5 and the magnifying means 6 are semi-fixed with the U-shaped fixture 22, but the transparent transparent plate 7, the image forming means 5 and the end of the magnifying means 6 are coated with an adhesive and adhered. Is also good.

In the present invention, fixing means fixing with an adhesive or ultrasonic welding, and semi-fixing means fixing with a fixture or clip as in this embodiment, or fixing with bolts and nuts. In other words, when detaching the transparent transparent plate 7, the image forming means 5 and the enlarging means 6 separately, it means fixing them so that they can be removed without breaking them.

The expanding means 6 composed of a concave Fresnel lens in the present invention does not change the effect of the present invention regardless of whether it has a Fresnel lens surface formed on both surfaces or a Fresnel lens surface formed on one surface. . However, when an object having a Fresnel lens surface formed on one side is used, in the present invention, the Fresnel lens surface is set to the imaging means 5 side. As a result, both sides of the assembly shown in FIG. 12 become flat plates, and are resistant to external contamination. Also, a transparent transparent plate 7 and an enlarging means 6
By making the plate thicknesses substantially the same, warpage of the assembled product shown in FIG. 12 does not remain. In addition, by making the material of the transparent plate 7 and the material of the enlarging means 6 the same, warpage of the assembled product shown in FIG.

Next, the enlarging means 6 composed of a concave Fresnel lens according to the present invention will be described with reference to the drawings using an embodiment.

FIG. 13 is a sectional view of a concave Fresnel lens 66 having a Fresnel lens surface on the light incident surface side according to the prior art, and FIG. 14 is a concave Fresnel lens 6 having a light incident surface side on the Fresnel lens surface according to the present invention. It is sectional drawing.

As described above, when a magnifying means 6 composed of a concave Fresnel lens is used which has a Fresnel lens surface formed on only one surface, the present invention places the Fresnel lens surface on the imaging means 5 side. ing. However, in this case, the following problem occurs.

This will be described with reference to FIG. The light beam d perpendicularly incident on the concave Fresnel lens 66 is refracted on the Fresnel surface i and further refracted on the emission surface j, and is emitted as a light beam d1. Similarly, a ray e vertically incident on the concave Fresnel lens 66 is also emitted as a ray e1, and the rays d1 and e1
Become parallel. However, the light ray f is refracted on the Fresnel surface i, is totally reflected on the Fresnel rising surface k, and is further refracted on the emission surface j, so that the light beam f1 becomes a light beam f1 and is not parallel to the light beams d1 and e1. This phenomenon continues up to the light beam g and actually appears as a ghost, which significantly impairs the image quality.

FIG. 14 is a sectional view of a concave Fresnel lens 6 according to the present invention, in which the light incident surface side is a Fresnel lens surface. The difference from the concave Fresnel lens 66 according to the prior art shown in FIG. 13 is that a flat portion m is provided at the top of the Fresnel. The flat portion m is provided with a black print n for shielding light. Accordingly, the light beams d, e, and g perpendicularly incident on the concave Fresnel lens 6 follow the same path as that of the prior art in FIG. 13 and emerge from the emission surface j, but become ghost by the concave Fresnel lens 66 of the prior art in FIG. G
Is not emitted as a ghost from the emission surface j because it is blocked by the black print n applied to the flat portion m provided at the top of the Fresnel.

Next, the width h of the flat portion m will be described.
Since the Fresnel angle θ of the concave Fresnel lens becomes smaller from the periphery to the center of the concave Fresnel lens, the range in which the ghost appears becomes smaller from the periphery of the concave Fresnel lens to the center and becomes zero at the center. Become. Since the width h of the flat portion m may be a minimum dimension without ghost, the width h of the flat portion m approaches zero as much as it goes toward the center of the concave Fresnel lens.

The transparent transparent plate 7 and the enlarging means 6 are used to bring the incident side microlens array 11 and the exit side microlens array 12 constituting the image forming means 5 into close contact with each other regardless of the initial warping direction. Used. Therefore, the transparent transparent plate 7 and the enlarging means 6 need to be flat, strong, and have a very small amount of deformation with respect to changes in temperature and humidity. Glass is a material satisfying this requirement, but it is extremely difficult to obtain a concave Fresnel lens by molding glass.

Hereinafter, a method for producing a concave Fresnel lens using glass as a base material according to the present invention will be described with reference to FIG. FIG.
5 is a sectional view of a concave Fresnel lens 6 according to the present invention, in which the light incident surface side is a Fresnel lens surface. In the figure, reference numeral 24 denotes a lens portion formed of an ultraviolet curable resin, 25 denotes a transparent film holding the lens portion 24 formed of the ultraviolet curable resin, 27 denotes a glass substrate, and 26 denotes the transparent film 24 and the glass substrate 27. Adhesive.

A fixed amount of an ultraviolet curable resin is placed on a mold (not shown), and a transparent film 26 is covered from above so as to prevent air bubbles from entering. Next, ultraviolet rays are irradiated from the transparent film side with an ultraviolet lamp (not shown) to cure the ultraviolet curable resin. By removing it from the mold, a transparent film 25 having a lens portion 24 formed of an ultraviolet curable resin is obtained.
An adhesive 26 is laminated on the transparent film 25 having the lens portion 24 formed of the ultraviolet curable resin. The adhesive 26 is desirably transparent, and an optical grade double-sided tape that does not use a base material can be used.

Finally, the transparent film 2 with an adhesive
The concave Fresnel lens 6 is completed by applying a roll to the glass substrate 27 from the end so that air does not enter the glass substrate 27.

The black print n for shading may be applied in the state of the transparent film 25 having the lens portion 24 formed of an ultraviolet curable resin, or may be applied after the transparent film 25 is attached to the glass substrate 27. both are fine.

Another embodiment of the concave Fresnel lens based on glass according to the present invention will be described with reference to FIG.

FIG. 16 is a sectional view of another embodiment of a concave Fresnel lens using glass as a base material. In the figure, the same numbers as those in FIG. 15 represent the same parts. The difference from FIG. 15 is that, in the present embodiment, the lens portion 24 formed of an ultraviolet curable resin is formed thicker at the central portion and thinner at the peripheral portion. As described in FIG. 12, the optical component according to the present invention has a configuration in which the imaging means 5 is sandwiched between the transparent transparent plate 7 and the magnifying means 6 from both sides. If the peripheral portion is formed thin, the incident-side microlens array 11 and the exit-side microlens array 12 that constitute the imaging means 5 are in tighter contact with each other.

[0063]

According to the present invention, there are provided an optical component and an image display device including an image forming means for preventing deformation due to separation of the entrance side micro lens array and the exit side micro lens array, which are thin and large molded products. I can do things.

Also, the microlens array on the input / output side can prevent the lens groups constituting the microlens array from causing optical axis shift or separating from each other with respect to temperature change, humidity change, and the like. Both can be brought into good contact with each other.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an image display device according to the present invention.

FIG. 2 is a cross-sectional view taken along line BB1 of the image display device shown in FIG.

FIG. 3 is a side view showing an embodiment of an imaging unit according to the present invention.

FIG. 4 is a perspective view of the image forming apparatus.

FIG. 5 is a cross-sectional view showing a state in which a mold for manufacturing a microlens array is filled with a resin.

FIG. 6 is a cross-sectional view showing a state in which a molded product is deformed in a mold.

FIG. 7 is a front view showing an embodiment of an imaging unit according to the present invention.

FIG. 8 is a cross-sectional view of the imaging unit CC shown in FIG. 7;

FIG. 9 is a cross-sectional view schematically illustrating a behavior due to a temperature change when a peripheral portion of the imaging unit is not fixed with an adhesive.

FIG. 10 is a cross-sectional view schematically showing a behavior of the imaging unit shown in FIG. 8 due to a temperature change.

FIG. 11 is a side view showing an embodiment of an optical component including an imaging unit according to the present invention before assembling.

FIG. 12 is a side view showing a state after assembling of one embodiment of the optical component including the imaging means according to the present invention.

FIG. 13 is a cross-sectional view for explaining a ghost generation mechanism when a concave Fresnel lens having a Fresnel surface on the image forming means side is used as the enlarging means.

FIG. 14 is a cross-sectional view of a concave Fresnel lens having a Fresnel surface on the image forming means side according to the present invention.

FIG. 15 is a cross-sectional view of one embodiment of a concave Fresnel lens having a Fresnel surface on the imaging means side according to the present invention.

FIG. 16 is a cross-sectional view of another embodiment of a concave Fresnel lens having a Fresnel surface on the image forming means side according to the present invention.

FIG. 17 is a plan view of a conventional image display device.

FIG. 18 is a cross-sectional view of the conventional image display device shown in FIG.
It is a side view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transmissive liquid crystal display element, 2 ... Backlight, 3 ... Cathode tube, 4 ... divergence angle control means, 5 ... Imaging means, 6 ... Enlargement means, 7 ... Transparent transparent plate, 8 ... Back projection screen , 9
... Partition wall plate, 11 ... Microlens array on incident side, 12 ...
Emission-side microlens array, 14 adhesive, 22 fixture.

Continued on the front page (72) Inventor Shuichi Hayashi 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in Digital Media System Division, Hitachi, Ltd. 2H091 FA27X FA29X FA42Z FA50Z FB02 FD06 FD13 FD14 GA01 LA04 LA30 MA07 5C094 BA43 DA02 ED01 HA08 5G435 AA14 AA17 BB12 BB15 BB16 BB17 CC09 DD02 DD04 DD07 DD09 FF02 FF07 GG02 GG06

Claims (30)

[Claims] 1. An optical system comprising: a light source for emitting light; light modulating means for modulating light from the light source to form a display image; and image forming means for projecting the display image formed by the light modulating means. An image display apparatus comprising: a component; and a rear projection screen that projects a display image projected by the optical component, wherein the imaging unit includes an incident-side microlens array and an emission-side microlens array. The incident-side microlens array and the exit-side microlens array are sandwiched between a first transparent plate and a second transparent plate, and the first and second transparent plates and the entrance-side and exit-side microlens arrays are sandwiched. An image display device wherein the optical component is configured by fixing or semi-fixing the end of the optical component. 2. The image display device according to claim 1, wherein said entrance side micro lens array and said exit side micro lens array are adhered or adhered to each other at a peripheral portion of said entrance / exit micro lens array. Image display device. 3. The image display device according to claim 2, wherein the incident-side microlens array and the output-side microlens array are formed by a heat-melting type film adhesive, a photo-curing adhesive, or ultrasonic welding. An image display device which is adhered or adhered to each other. 4. The image display device according to claim 1, wherein said second transparent plate is an enlarging unit. 5. The image display device according to claim 4, wherein said enlargement means is a concave Fresnel lens. 6. The image display device according to claim 5, wherein a lens portion of said concave Fresnel lens is formed of an ultraviolet curable resin on said second transparent plate. 7. The image display device according to claim 6, wherein the lens portion of the concave Fresnel lens formed of the ultraviolet curable resin is provided on the second transparent plate with a transparent adhesive or an adhesive via a transparent film. An image display device, wherein the image display device is attached to an image display device. 8. The image display device according to claim 6, wherein the lens portion of the concave Fresnel lens formed of the ultraviolet curable resin has a greater thickness at a central portion than at a peripheral portion. Image display device. 9. The image display device according to claim 5, wherein said concave Fresnel lens is arranged such that its Fresnel surface is in contact with said emission side microlens array. Display device. 10. The image display device according to claim 9, wherein
An image display device, wherein the concave Fresnel lens has a flat portion formed on the top of the Fresnel, and black printing for light shielding is performed on the flat portion. 11. The image display device according to claim 10, wherein the width of the flat portion formed on the top of said concave Fresnel lens is all the same or gradually reduced from the peripheral portion to the central portion. Image display device. 12. The image display device according to claim 1, wherein the first and second transparent plates have the same thickness. 13. The image display device according to claim 1, wherein said first and second transparent plates are made of the same material. 14. The image display device according to claim 1, wherein a material of said first and second transparent plates is glass. 15. The image display device according to claim 1, wherein
The image display device, wherein the light modulation unit is a transmission type liquid crystal display element that transmits light from the light source and modulates the transmitted light based on an input image signal. 16. The image display device according to claim 1, wherein
The image display device, wherein the light modulation unit is a reflective display device that reflects and modulates light from the light source based on an input image signal. 17. An optical component comprising image forming means for projecting a display image formed by light modulating means for modulating light from a light source onto a screen, wherein said image forming means comprises:
An incident-side microlens array; and an exit-side microlens array. The incident-side microlens array and the exit-side microlens array are sandwiched between a first transparent plate and a second transparent plate. A transparent plate and the incident side,
An optical component including an imaging unit, wherein an end of the emission-side microlens array is fixed or semi-fixed. 18. The optical component according to claim 17, wherein the incident-side microlens array and the exit-side microlens array are bonded or adhered to each other at a peripheral portion of the input / output microlens array. Optical components. 19. The optical component according to claim 18, wherein the incident-side microlens array and the output-side microlens array are connected to each other by a heat-melting film adhesive, a photo-curing adhesive, or ultrasonic welding. An optical component characterized by being adhered or adhered. 20. The optical component according to claim 17, wherein said second transparent plate is an enlarging means. 21. The optical component according to claim 20, wherein said magnifying means is a concave Fresnel lens. 22. The optical component according to claim 21, wherein a lens portion of said concave Fresnel lens is formed of an ultraviolet curable resin on said second transparent plate. 23. The optical component according to claim 22, wherein the lens portion of the concave Fresnel lens formed of the ultraviolet curable resin is attached to the second transparent plate with a transparent adhesive or an adhesive via a transparent film. An optical component characterized by being pasted. 24. The optical component according to claim 22, wherein the lens portion of the concave Fresnel lens formed of the ultraviolet curable resin has a greater thickness at a central portion than at a peripheral portion. Optical components. 25. The optical component according to claim 21, wherein said concave Fresnel lens is arranged such that a Fresnel surface thereof contacts said emission-side microlens array. . 26. The optical component according to claim 25, wherein the concave Fresnel lens has a flat portion formed on the top of the Fresnel, and the flat portion is black printed for light shielding. Optical components. 27. An optical component according to claim 26, wherein the width of the flat portion formed at the top of said concave Fresnel lens is all the same or gradually reduced from the peripheral portion to the central portion. parts. 28. An optical component according to claim 17, wherein said first and second transparent plates have the same thickness. 29. The optical component according to claim 17, wherein said first and second transparent plates are made of the same material. 30. The optical component according to claim 17, wherein a material of said first and second transparent plates is glass.