JPH0618811A - Display device - Google Patents

Abstract

PURPOSE:To provide a miniaturized and thin display device displaying image information on a transparent plate by making the transparent plate as a light transmission plate so as to introduce light and displaying the image on this transparent plate. CONSTITUTION:When this display device is applied to an image inputting device, an original placing plate 4 is composed of a glass plate as a light transmission plate, an illuminating light source 5 and a light collector 6 are arranged at the end face and a hologram layer 67 designating the size of an original is provided on the original placing plate 4. The illumination light from the illuminating light source 5 is introduced to the original placing plate 4 as the light transmission plate and the light beam for display from the hologram provided on the upper part is transmitted towards the operator side. After displaying the original while fitting to this displayed beam, image inputting is started by the operator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to an image scanner, a copying machine, a video image pickup machine, a camera, a vehicle head for reading an image using an evanescent wave hologram or a waveguide optical hologram. The present invention relates to a display device that displays an image on an up display or the like.

[0002]

2. Description of the Related Art An image input device for reading an image of a document is
A manuscript table is made of a transparent glass plate, and under this manuscript table, an equal-magnification imaging element or a reduction optical system and a CCD (Charge Coupled
(Device) sensor is arranged and scanned to input the image information of the document on the document table to the CCD. Generally, the original is placed on the platen with the image information facing downward. At this time, it is desired that the image is not changed on the platen. Therefore, the transmittance of tempered glass, curing plastic, etc. And a high strength is used.

11 and 12 show a conventional example of an image input device having an image input area of A3 size.
In FIG. 11, 1 is an image input device, 4 is a document setting table on which a document is placed, and 25 is a document placed with the image information on the lower surface. Reference numerals 23a, b, and c indicate the installation positions of A3 size documents according to the JIS standard, and 24a and b.
Is an installation position display of an A4 size document. In FIG. 12, reference numeral 26 denotes a CCD camera section, which includes a mirror 27, an imaging lens 28, a CCD 29,
It is composed of an illumination light source 64 and a condenser 65.

For example, when inputting image information of an A4 size original, the original 25 is abutted on one end face 63 in the longitudinal direction of the original placing table 4, and both end faces in the lateral direction are displayed on the installation position display 24b. Install so that they match. Also,
At this time, it is confirmed whether the other end in the longitudinal direction coincides with 24a. Thereafter, at the same time as illuminating the original 25 with the illumination light from the illumination light source 64 condensed by the condenser 65,
The CCD camera unit 26 is horizontally moved in the direction of the arrow 30 to input image information. In general, a cover (not shown) is arranged on the upper part of the document setting table 4, and the cover is covered so that light from the outside other than the illumination light source 64 does not enter the CCD camera unit 26.

On the other hand, as a technique for handling image data, there is a technique related to a head-up display as a display device for displaying image information on a windshield for an automobile.
It is proposed in Japanese Patent No. 308120. In this head-up display, a display device is provided in a dashboard, display light is projected on a windshield, a combiner having a high reflectance is provided on the windshield, and a driver observes the display light on the windshield. If a convex lens or a concave mirror is used as part of the display device, it is possible to display a virtual image. A combiner is required to have a high transmittance of foreground light and a high reflectance of display light, and a hologram combiner and a multilayer film combiner are used.

13 and 14 show a conventional example of a head-up display. FIG. 13 shows a side view, 31 is a windshield, 39 is a handlebar, 4
0 is a head-down display, 41 is a dashboard, 42 is a roof, 43 is a half-mirror combiner,
Reference numerals 44 denote head-up display devices provided in the dashboard 41, respectively. The head-up display device 44 includes a fluorescent display tube 45 and a virtual image magnifying lens 46. On the other hand, 36 is a driver, 37
Is the eye of the driver 36, 38a is the line of sight to the head-up display, and 38b is the line of sight to the head-down display 40. In such a conventional head-up display, the light from the fluorescent display tube 45 of the head-up display device 4 is magnified by the virtual image magnifying lens 46, and a predetermined display is performed on the half mirror combiner. The display light 47 reflected by the half mirror is the driver 3
Recognized by 6. In FIG. 14, an abnormal state of the exhaust temperature is displayed as the display light 47.

[0007]

In the case of an image input device for reading an image of a document, when the document 25 is set on the document table 4, the reading range of the document 25 and the size of the document table 4 are completely the same. Then, the operator can easily cause the CCD 29 to read the image information after placing the original without any displacement. However, in general, the image input device has the document table 4
Is made larger than the largest readable original. For this reason, a positional deviation occurs between the size of the original and the reading range of the image. Further, the position indications 23a, 24a, etc. indicating the installation position of the document are provided on the periphery of the document table 4. Therefore, in the case of inputting image information of a document of A4 size with an image input device capable of reading up to A3 size, the position indication 24a in three directions other than the end face 63 on which the document 25 is abutted does not match the document. It became difficult to confirm and it was difficult to place the manuscript.

It is possible to display a B4 size image input range by installing a light emitter on the back surface of the document table 4, but it is difficult to put it into practical use because of an optical system for image input. Further, if the document table is provided with a function as a diffusion plate, the image input range can be easily displayed, but it is not suitable for practical use because the image information at the time of image input is deteriorated. There is also a method of placing the originals with two sides attached, which generally makes it easier to place the originals, but it is easier to make streaks on the end face in two places, and for documents that are closed with staples or clips, double-page spreads, magazines, etc. The original may be difficult to set because the original is placed on the edge of the original table. Further, there is a problem that the optical system becomes heavy to be used as an image input unit of an analog copying machine. In addition, the end surface with the original attached is
A small gap is likely to be created between the abutted part and the original due to paper bending, etc. Due to the thickness of the original, it was easy for shadows to be created by illumination light and black streaks on the edge of the original.

On the other hand, in the case of a head-up display in which a predetermined image is displayed on the windshield of an automobile, the windshield 31 is often required to have a transmittance of 70% or more of the foreground light. However, although the half mirror combiner 43 is generally manufactured by a multi-layer coating of oxide, it is difficult to achieve both high transmittance for foreground light and high reflectance for display light. For this reason, although it has been put to practical use by narrowing the wavelength range of the display light to match the wavelength characteristics of the combiner or increasing the illuminance of the display light, there is a certain limit to increasing the reflectance. However, there is a problem that the display portion becomes large because it is necessary to increase the brightness of the display light as compared with the normal display. Further, by using a hologram element as the half mirror 43 and utilizing its high wavelength dependence,
Although there is a method of ensuring a high reflectance, it is necessary to sharpen the wavelength characteristic of the display device. Therefore, when the conventional fluorescent display tube 45 is used, the P15G2, which is a general high-intensity phosphor, has a wavelength of 50.
Because of the broad emission spectrum centered at 5 nm,
The combination with the hologram element is not very effective.

Further, in the conventional head-up display, since only the half mirror is provided on the windshield, it is necessary to provide a display device and an optical system for displaying a virtual image on the dashboard portion. The dashboard is one of the densest parts in the automobile, and the provision of a new space for the head-up display device 44 in the dashboard places a greater constraint on other parts. In particular, since a normal head-up display displays a virtual image, a certain distance is required between the virtual image magnifying lens 46 and the fluorescent display tube 45, and miniaturization is difficult. Therefore, a special dashboard design is required. Was needed.

Therefore, the present invention has been made to solve such a problem, and guides light by using a transparent plate as a light guide plate and displays on the transparent plate to display image information on the transparent plate. An object is to provide a small and thin display device capable of displaying.

[0012]

According to a first aspect of the present invention, a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and the transparent substrate using the light from the light source as reference light are provided. A display device having a hologram formed by:
The transparent substrate is provided on at least a part of the document placing table of the document image information input device, and image display light such as guide light for the document installation position and display light for instructions at the time of image input is displayed by the hologram light. . According to a second aspect of the present invention, there is provided a display device including a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using light from the light source as reference light. Then, the transparent substrate is provided on at least a part of the glass of the vehicle, and the hologram light is used as display light for the driver.

In a third aspect of the present invention, a display having a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using the light from the light source as reference light In the device, the transparent substrate is provided in a finder portion of a spatial image information input device, and guide light for an image information input position or display light for instructing image input is displayed by hologram light. According to a fourth aspect of the present invention, there is provided a display device including a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using the light from the light source as reference light. Then, the transparent plate is used in front of a display device for displaying image information, and the hologram light is added to the display light of the display device.

[0014]

EXAMPLES In the examples described below, holograms are displayed by using light from the light guide plate as reference light, and an evanescent wave hologram is provided on the light guide plate substrate, or the light guide plate itself acts as a hologram. This evanescent wave hologram is a hologram that uses an evanescent wave that has penetrated into a recording material as reference light in the state of total reflection at the boundary surface, and is based on a refractive index modulation type or a relief type. Further, by periodically changing the refractive index or the transmittance of the light guide plate itself, this can be made into a hologram. Further, even emitted light which is not totally reflected from the light guide plate can be made into a hologram by the light from the light guide plate by manufacturing or adhering a hologram on the light guide plate. There is also a hologram in which a waveguide light, which is a light beam propagating in a waveguide that is a kind of light guide plate, is used as a reference light. The medium (core portion or outer peripheral portion) of the waveguide itself is a hologram, and the reference optical waveguide and the hologram are integrated.

An embodiment in which such a display device is applied to various devices will be described in detail with reference to FIGS. 1 to 10. 1 and 2 show a first embodiment used in an image input device having an A3 size image input area as a display device. FIG. 1 is a schematic diagram and FIG. 2 is a sectional view. is there. In addition, in order to simplify the description, FIGS.
The same parts as those of the conventional display device shown in are attached with the same notations and an explanation thereof will be appropriately omitted. In FIG. 1, 1 is an image input device, 2a and 2b are position indications of document placement positions of A3 size documents, 66a and 66b are placement position indications of A4 size documents, and 3 is an image input area for A3 size documents. Outside 4 is a document setting table. Further, in FIG. 2, 5 is a linear illumination light source, 6
Is the light collector and the hologram layer 67 on the document table 4. The illuminating light from the illuminating light source 5 is made of a glass plate as a document setting table, and is made to be a light guide plate, and is directly coupled to the end face to be guided and incident.

In general, the light incident from the end surface of the light guide plate from the air has a refractive index n of the light guide plate of 1 / sin (π / 4) = 1.
If it is larger than 414, it is totally reflected and travels through the light guide plate. Since the ordinary glass plate has a larger refractive index,
The light that has entered the light guide plate can be totally reflected with high efficiency to travel through the light guide plate. Therefore, if the absorption of the illumination light in the light guide plate is made as small as possible, a sufficient amount of light can be secured regardless of where the hologram is formed on the light guide plate. Also,
In general, a glass plate (n = 1.5) has a high transmittance of about 90% or more when the incident angle is within 20 degrees. Therefore, it is effective to provide a cylindrical lens between the illumination light source and the end face of the glass plate. Can be combined with. A non-reflective coating is also effective.

By providing a hologram at a specific portion on the light guide plate, hologram light with the illumination light in the light guide plate as the reference light can be emitted above the document placement plate, that is, to the operator side of the image input device. it can. The operator displays the document in accordance with this display and then starts image input. Note that the illumination of the light guide plate is stopped when this image is input.

FIG. 3 is for explaining the principle of the hologram by the light guide plate. In FIG. 3, 7
Is a hologram element provided on the light guide plate, 8a is a ray of illumination light which is incident on the boundary surface of the light guide plate at an incident angle of 45 degrees, and 9a is a light source of illumination light which is incident on the boundary surface of the light guide plate at an incident angle of 60 degrees.
Is a certain point where two rays are incident on the hologram element, 1
Reference numerals 1a and 11b denote eyes of an operator of the image input apparatus, and angles 12 and 13 denote angles θ1 and θ2 formed by the light guide plate boundary surface and the light rays 8a and 8b, respectively. In fact, in direct end face coupling, ordinary glass (for example, Pyrex, quartz, Co 7059, etc.) has a refractive index of 1.41 or more, so it is necessary to tilt the end face to obtain a totally reflected light beam with an incident angle of 45 degrees. Although some ingenuity is required, here, for the sake of simplicity, Corning Inc. 7059 with a refractive index n = 1.54 is used, taking incident angles of 45 degrees (θ1 = 45) and 60 degrees (θ2 = 30) as examples. .

Propagation constant kz of the light beam in the light guide plate in the z direction
Is expressed by the following equation (1), where λ is the wavelength of the illumination light and α is the angle formed by the light rays with the z axis. kz = nkcos (α) = (2nπ / λ) cos (α) (1) Further, when the period in the z direction of the hologram element is Λ, the grating vector K of the hologram element is It is expressed by equation (2). K = 2π / Λ (2) Further, when the illumination light is emitted from the hologram element in the air (refractive index 1.0), the following equation (3) is established in consideration of spatial harmonics. The light is emitted in the direction of the propagation angle β (β is an angle formed with the x axis). k · sin (β) = kz + q · K (3) In the expression (3), q = 0, ± 1, ± 2 ,.

To emit in the vertical direction, β = 0,
Considering the −1st order diffracted light of q = −1, the illumination light source has 680
LD light having a wavelength characteristic of nm is incident on the light guide plate,
And 0.6 at incident angles of 60 degrees and 60 degrees
Periods of 24 μm and 0.510 μm are required. The hologram element having this period can be easily manufactured by, for example, a resist photolithography process. When the period of the hologram element is set to 0.624 μm, a light ray having an incident angle of 45 degrees is emitted perpendicularly to the light guide plate as described above, and a light ray of 60 degrees has β = 14.1 degrees and 45 degrees. If there are continuous rays between 60 degrees and 60 degrees, then β = 0 to β = 14.1
It is possible to continuously observe the hologram light during a period of time. In practice, the light rays in the light guide plate exist up to an incident angle of about 90 degrees with respect to the boundary surface of the light guide plate, so β = 0 to 9
Hologram light can be observed in a wide viewing range of 0.

By appropriately setting the period of the hologram element with respect to the refractive index and wavelength of the light guide plate, it is possible to adjust the viewing zone and the angle at which the brightness is large. In addition, these adjustment ranges are expanded by continuously changing the cycle. Further, even with illumination light having multiple wavelengths instead of a single wavelength, it is possible to change the image information to be displayed depending on the position to be observed by utilizing the fact that the hologram element composed of the volume hologram has high wavelength dependency. It is also possible to change an image to be displayed by using LEDs having a half width of a plurality of wavelengths which are small. Further, by making the direction of the incident light beam sufficiently thin and changing the incident angle, the displayed image can be changed.

The display using these hologram elements directly displays the edge of the original on the original surface on the original table.
The position of the original can be adjusted accurately. Further, since the original placing table is used as the light guide plate, the space under the original placing table is not used, and it is difficult to be restricted by other parts of the image input device. In addition, a wide viewing area can be secured even though the display is made on a transparent glass plate. Also,
With this method, it is not necessary to touch the edges of the original,
It is also easy to input an image with the center of the document setting table as the center of an A4 size document. This is an imaging lens and 2
When inputting an image using a three-dimensional CCD, the central portion of the lens can be used, and thus it is easy to obtain a lens in which optical aberration is favorably corrected.

At the time of image input, the hologram light is not emitted to the original by stopping the illumination light to the light guide plate, but this time, the illumination light of the CCD camera is transmitted through the hologram element in a substantially vertical direction. Therefore, it is necessary that the illumination light is hardly affected by the hologram element. If the originals are in close contact with each other, the influence of the hologram element may be considered as a decrease in the amount of light at the hologram element portion. For this reason, there are methods such as utilizing the high angle dependency of this hologram element, reducing the transmittance except for the hologram element portion, and detecting the hologram element portion to correct the image information.

Since it is rare to see the hologram element from directly above when placing the original, if the hologram element is set so as not to emit the illumination light in the light guide plate in the vertical direction, on the contrary, the light is incident in the vertical direction. Since it becomes difficult for light to be coupled to the light guide plate, if the hologram element is manufactured by phase modulation such as a change in refractive index or unevenness, the 0th order light of the illumination light at the time of image input to the hologram element can be increased and the transmittance can be increased. Can be increased. Further, by covering the portion other than the hologram element portion with the ND filter, it is possible to make the transmittance of the entire surface of the document placing table constant. Alternatively, after the image information of the entire surface of the document is stored in advance by the image input device, the image information may be corrected based on the known position information of the hologram element of the hologram element portion.

Alternatively, after the image information is stored by the image input device, the hologram element portion may be detected based on the input image information and the image information of this portion may be corrected. For example, in the case of a display for an A4 size document, the characters "A4" and the thin line indicating the document end face can be easily identified. Also, the hologram element is, for example, a high-definition 400 dp
In the image input of i, one dot is about 64 μm, and 0.6
A hologram element with a μm pitch can be manufactured within the size of this one dot, and the absolute value of the affected area can be made extremely small. Further, the light guide plate is provided with a reflection coating on the end surface other than the incident surface of the illumination light, or a member having a high reflectance is provided, so that the light once incident on the light guide plate can be effectively used.

Various holograms can be used for these hologram elements in addition to the hologram formed by the periodic unevenness on the glass substrate shown in FIG. FIG. 4 is an example thereof. FIG. 4A shows a layer 1 in which the refractive index is changed periodically.
4b is provided and can be manufactured by ion diffusion or the like to the inorganic oxide layer 14a. Further, the polymer film may be provided with a periodic refractive index distribution and fused. Figure 4
In (b), the glass substrate itself is provided with periodic concavities and convexities 15, which can be manufactured by etching glass. Figure 4
In (c), a periodic refractive index distribution 16 is provided on the glass substrate itself. FIG. 4D shows the polymer film 17
A periodic refractive index distribution 17b is attached to a, and the adhesive layer 68 is attached to the periodic refractive index distribution 17b, so that the refractive index of the adhesive is close to that of glass.

Further, it is possible to manufacture a waveguide on the glass substrate 4 to form a waveguide hologram. Figure 5
It shows the waveguide hologram. Figure 5 (a)
The beam light 20a is made incident on the waveguide 18 by the end face coupling method to be guided light 20b. The guided light 20b is partly emitted in the direction of 20c due to the periodic unevenness 19 provided on the waveguide. Further, in FIG. 5B, the waveguide 18 is manufactured between the inorganic oxide layer 21a and the glass substrate 4, and
By providing the periodic refractive index distribution 21b in 1a,
Hologram light can be taken out. In the case of hologram elements of these waveguides, various holograms can be used as in FIG.

FIG. 6 shows a case where a hologram is provided on the back surface of the glass substrate. The light ray 22a in the glass substrate is totally reflected and becomes 22b, which is incident on the hologram element and is emitted as 22c. In this case, although the positional accuracy is reduced by the thickness of the glass substrate, the original and the hologram element do not come into direct contact with each other, so that the durability of the hologram element is improved.

Next, a second embodiment in which the display device of the present invention is applied to a head-up display will be described. 7 and 8 show this embodiment of the head-up display. FIG. 7 is a side view of the head-up display. In this figure, 31 is a windshield, 32 is a hologram element, 33 is an illumination light source, and 34 is
Is a condenser, 35 is an illumination light to the end surface of the light guide plate, 36 is a driver, 37 is a driver's eye, 38a is a line of sight to the head-up display, 38b is a line of sight to the head-down display, 39 is a steering wheel, 40 Is a head-down display, 41 is a dashboard, 42 is a roof, and 69 is display light emitted from the hologram element 32.

FIG. 8 shows a state in which an abnormality in exhaust temperature is displayed as a hologram displayed on the head-up display. The illuminating light 35 of the illuminating light source is made to enter from the end face of the lower part of the glass, and this is applied to the hologram element
And emits it as display light 69 at the line of sight 38a to the driver,
Observe on the foreground of the windshield 31. Here, it is possible to display a plurality of pieces of image information by narrowing the incident illumination light and changing the area of the hologram element 32 that can be illuminated. Moreover, a plurality of pieces of image information can be displayed by changing the wavelength of the illumination light 35.

Since the windshield 31 is used as a light guide plate and the illumination light 35 is introduced from this end face, a spatially very small display device can be obtained.
The arrangement position on the dashboard 41 is also near the end surface of the windshield 31, so the head-down display 40
Further, it is possible to arrange each component in a portion far from the handlebar 39 and less dense than the conventional head-up display. Further, the hologram element 32 can make the portion of the foreground where the transmittance is reduced to a very small area corresponding to the amount of display, and as a result, the foreground can be easily observed.

In addition, in these holograms, the first
Various holograms can be used according to each application, as in the above embodiment. In addition to the windshield, this display device can also be used for a stop lamp display, a blinker display for the rear glass, a display for the side glass, or the like. Since the side glass is often moved up and down, the illumination light can be incident on the hologram element regardless of the position by entering the illumination light from the end face. Further, it can be applied to a foreground of an airplane or a train other than an automobile and a head-up display for observing a display device through a windshield.

Next, a third embodiment in which the display device of the present invention is applied to a finder will be described. FIG. 9 is a side sectional view for explaining the structure of the finder of this embodiment.
In FIG. 9, 48 is a backlight, 49 is a liquid crystal display, 50 is a lens, 50a is a hologram element,
51 is a viewfinder lens barrel, 52 is an observer's eye, and 53 is LE
D, 54a, 54b are two types of light rays 55a, 5a, which are emitted from the LED 53 and are incident using the lens 50 as a light guide plate.
5b represents each emitted light. On the surface of the lens 50, a display such as a battery exhaustion warning is prefabricated with the hologram element 50a.

When the observer observes the virtual image of the image information on the liquid crystal display 49 through the lens 50 and the battery runs out, the illumination light 55 of the LED 53 is emitted.
A and 55b are made incident from the end face. At this time, the lens acts as a light guide plate, and exits from the hologram element 50a as short as the light rays 54a and 55a, or 54b and 55.
After being reflected by the end surface of the lens 50 one or more times as shown in b, it is emitted from the hologram element 50a. In the latter case, since the lens surface has a curvature, the original emission angle of the vertically emitted light beam is often different. As a result, hologram display light such as a dead battery warning is superimposed on the image information observed by the viewfinder, and the observer can be made aware of the dead battery.

Also in the third embodiment, a plurality of image information can be observed and various holograms can be used, as in the first embodiment. Further, a flat transparent plate having no curvature may be used without using the lens as the light guide plate. For example, it can be used for a microscope or a telescope using an eyepiece.

Next, a fourth embodiment in which the display device of the present invention is applied to a timepiece will be described. FIG. 10 is a front view (a) and a side sectional view (b) for explaining the configuration of the timepiece of this embodiment. In this figure (a), 56 is a frame,
57 is a base, 58 is a glass plate, 59a is a long hand, 59b is a short hand, 60 is a hologram element on the glass plate, and 62 is a belt. In addition, in FIG.
1 is the display light emitted from the hologram element 60,
Reference numeral 70 represents an LED as an illumination light source, and 71 represents illumination light from the LED 70 which is incident on a glass substrate as a light guide plate.

In this embodiment, the long hand 59a and the short hand 59b are used.
Since it is possible to display different types of image information such as a display position, a display distance, a display color, and a viewing angle dependency in comparison with a normal display by, the display with excellent visibility can be performed. . In addition, the display device behind this is different from the mechanical clock display such as the short hand and the long hand, and the appearance when displaying is different even on the front face of the display device that displays various information such as a liquid crystal display and a fluorescent display tube. This is effective when displaying highly visible image information. Also in this embodiment, a plurality of image information can be observed and various hologram elements can be used.

[0038]

According to the display device of the present invention, a document placing table made of a transparent substrate is used as a light guide plate, and a hologram using the light inside the light guiding plate as reference light is provided on the transparent substrate to set a document placement position. Since the guide light or the display light for instructing the image input is displayed by the hologram light, it is possible to directly display the document setting position on the document setting table. The display device according to claim 2, wherein a transparent substrate is used as a light guide plate, and a hologram having the light inside the light guide plate as reference light is provided on the transparent substrate, and the transparent plate is provided on at least a part of the glass of the vehicle. Since the light is used as the display light for the driver, it can be displayed as a small head-up display. In the display device according to claim 3, a transparent substrate is used as a light guide plate, and a hologram whose light in the light guide plate is used as reference light is provided on the transparent substrate, and the transparent substrate is provided at a finder portion of a spatial image information input device. Since the guide light for the image information input position or the display light for instructing the image input is displayed by the hologram light, it is possible to display the other image information on the image of the finder. In the display device according to claim 4, a transparent substrate is used as a light guide plate, and a hologram whose light in the light guide plate is used as reference light is provided on the transparent substrate, and this transparent plate is used in front of the display device for image information. Since the hologram light is added to the display light of the device, highly visible image information can be displayed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline when a display device according to a first embodiment of the present invention is applied to an image input device.

FIG. 2 is a side sectional view showing the structure of the first embodiment.

FIG. 3 is an explanatory view of the principle of a hologram by the light guide plate of the first embodiment.

FIG. 4 is an explanatory diagram showing a modification of the hologram element of the first embodiment.

FIG. 5 is an explanatory diagram showing another modification of the hologram element according to the first embodiment.

FIG. 6 is an explanatory diagram showing still another modification of the hologram element according to the first embodiment.

FIG. 7 is a side sectional view showing a configuration when the display device according to the second embodiment of the present invention is applied to a head-up display.

FIG. 8 is an explanatory diagram showing a state in which a hologram is displayed according to the second embodiment.

FIG. 9 is a side sectional view showing a configuration when a display device according to a third embodiment of the present invention is applied to a finder.

FIG. 10 is a configuration diagram when a display device according to a fourth embodiment of the present invention is applied to a timepiece.

FIG. 11 is a perspective view of a conventional image input device.

FIG. 12 is a side sectional view showing the configuration of the image input device of the above.

FIG. 13 is a side sectional view showing a configuration of a conventional head-up display.

FIG. 14 is an explanatory diagram showing a display state of the head-up display of the above.

[Explanation of symbols]

 1 Image Input Device 2a, 2b, 66a, 66b Document Setting Position Display 4 Document Setting Table 5, 33 Illumination Light Source 6, 34 Condenser 26 CCD Camera Section 67 Hologram Layer 31 Front Glass 32 Hologram Element 36 Driver 39 Handle 41 Dash Board 48 Backlight 49 Liquid crystal display 50 Lens 50a Hologram element 51 Finder barrel 53 LED 56 Frame 57 Base 58 Glass plate 59a Long hand 59b Short hand 60 Hologram element on glass plate 70 LED as illumination light source

Claims (4)

[Claims] 1. A display device comprising a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using the light from the light source as reference light, A transparent substrate is provided on at least a part of the document table of the document image information input device, and image display light such as guide light for the document installation position and display light for instructions at the time of image input is displayed by the hologram light. Display device characterized by. 2. A display device having a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using the light from the light source as reference light, A display device, wherein a transparent substrate is provided on at least a part of glass in a vehicle, and the hologram light is used as display light for a driver. 3. A display device comprising a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using the light from the light source as reference light, A display device characterized in that a transparent substrate is provided in a finder portion of a spatial image information input device, and guide light for an image information input position or display light for instructing image input is displayed by hologram light. 4. A display device comprising a transparent substrate, a light source for introducing light into the transparent substrate from a side surface, and a hologram provided on the transparent substrate using the light from the light source as reference light, A display device, wherein a transparent plate is used in front of a display device for image information, and the hologram light is added to the display light of the display device.