JP3320429B2 - Holographic display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic display device suitable for displaying warning information, for example, in a vehicle display device.

[0002]

2. Description of the Related Art A conventional vehicle display device of this type will be described with reference to FIGS. 9 and 10,
An instrument panel 1 is provided in front of an analog instrument panel 11 provided in a cluster box 10 of an instrument panel.
A transparent glass front glass 12 for protecting the glass 1 is provided, and a different alarm state, for example, a shortage of engine oil, is provided on a lower surface of the front glass 12 on the instrument panel 11 side.
Pattern 12a ₁ to 12 of a battery voltage drop, etc. of
transmission type image holograms 12a to a ₉ is recorded is formed.

The transmission type image hologram 12
a is formed in a blank portion (dead space) of the instrument panel 11, and reproduced hologram images A _{1 to} A ₉ are displayed on the instrument panel 11.
Display is not prevented.

A reproducing light source 13 such as a white lamp is provided at a position corresponding to a position of a later-described reference light source used at the time of recording the hologram image A and at a position invisible from the driver's viewpoint E. A lens 14 for intensively irradiating light from the reproduction light source 13 to the transmission type image hologram 12a is provided on the front surface of the reproduction light source 13, and further, on the front surface of the lens 14, a red or light for specifying a reproduction color is provided. A color filter 15 for a color is provided.

The reproduction light source 13, lens 14, and color filter 15 are composed of a plurality of patterns 12a ₁ to 12a _1.
2a ₉ are arranged at corresponding positions, and the light-color filters 15 are 12a ₂ , 12a ₄ ,
12a for ₆ and 12a _{8, 1} red color filter 15 is _{12a, 12a 3, 12a 5,} 12a 7 and 1
2a ₉ is provided. Above Symbol reproduction light source 13,
The lens 14 and the light-color filter 15 serve as a reproduction light source for generating reproduction light in the light-emission wavelength band.
The lens 3, the lens 14, and the red color filter 15 each constitute a reproduction light source that generates reproduction light in a red emission wavelength band. That is, a plurality of types of reproduction light which are provided corresponding to each pattern and generate reproduction light of a specific emission wavelength band which is the same as the laser light at the time of pattern recording and reproduction light of a different specific emission wavelength band, respectively. A light source is provided.

Next, the transmission type image hologram 12
The recording method of a will be described with reference to FIG. In addition,
A red laser is used as the recording light.

First, the master hologram 121a is recorded in the master hologram recording optical system shown in FIG. The pattern film 121b on which the pattern indicating the alarm state is arranged is set such that the illumination light enters at a predetermined angle θ ₁ (pattern inclination angle). A white diffusion plate 121c for diffusing the illumination light is attached to the surface of the pattern film 121b on the side where the illumination light is incident. Further, a recording material 122a for forming the master hologram 121a is provided so that the object light from the pattern film 121b is incident at a right angle.

Then, the illumination light is incident on the pattern film 121b from the white diffuser plate 121c side, passes through the pattern film 121b, and becomes a recording material 122 as object light.
a, and the reference light is shifted with respect to the direction of the object light.
The light is made to enter the recording material 122a at a predetermined angle θ ₂ (reference light incident angle). Thereby, the master hologram 121a
Is recorded.

Next, in the final hologram recording optical system shown in FIG.
Record a. Reconstructed light is incident on the master hologram 121a at a predetermined angle θ ₃ (reproduced light incident angle), passes through the master hologram 121a, and is converted into final hologram 12 at a predetermined angle θ ₄ (object light incident angle) as object light.
a, and the reference light is incident at a predetermined angle θ ₅ (reference light incident angle) with respect to the normal direction of the surface of the recording material 123a. As a result, a final hologram, that is, a transmission image hologram 12a is recorded.

Here, the reference light incident angle θ ₂ when recording the master hologram 121a, the reproduction light incident angle θ ₃ when recording the final hologram 12a, the pattern tilt angle θ ₁ when recording the master hologram 121a, and the final hologram 12a.
The object light incident angles θ ₄ during recording are equal.

Since the pattern of the pattern film 121b and the pattern recorded on the final hologram 12a are reversed (the left and right sides are reversed), the pattern of the pattern film 121b when recording the master hologram 121a indicates this fact. It must be arranged with consideration.

When an alarm condition occurs, the reproduction light source 13 is activated.
Is turned on, and as shown in FIG. 12, the reproduction light is transmitted through the color filter 15 to a predetermined angle θ ₆ (reproduction light incident angle).
Enters the transmission type image hologram 12a, is transmitted by the transmission type image hologram 12a, and has a predetermined angle θ.
₇ (hologram image emission angle), and the hologram image A ₁
Of to A _9, only the hologram image pattern corresponding to the warning generated is selectively reproduced, it is visible to the driver. The reproduction light incident angle θ ₆ and the hologram image emission angle θ ₇
Is determined by the shape of the display device, the position of the driver's viewpoint E, and the like. In addition, the reproduction light incident angle θ ₆ and the reference light incident angle θ ₅ when recording the final hologram 12a are set equal, and the hologram image emission angle θ ₇ and the object light incident angle θ ₄ when recording the final hologram 12a are set equal.

[0013]

[SUMMARY OF THE INVENTION The transmission type image hologram 12a is because it has a broad reproduction wavelength spectrum, the reproducing light incident angle theta ₆ equal to the reference beam incident angle theta ₅ during final hologram 12a recording, reproducing light In the case of using the color filter 15 having a light color that transmits the reproduction wavelength spectrum when the light is incident, the hologram images A ₂ , A ₄ , A ₆ and A ₈ are visually recognized in the light color at the center of the visual field. However, since the transmission-type image hologram 12a has an angle dependence of the reproduction wavelength spectrum, when the viewpoint is moved downward, the light color changes from red to red and the red color filter 15 is used. The colors are the same as those of the hologram images A ₁ , A ₃ , A _5, and A ₇ , so that the reproduced color cannot be changed according to the type of the warning display.

In order to optimize the reproduction color, a method of changing the reproduction wavelength of the transmission type image hologram 12a is to subject the hologram emulsion layer to swelling or shrinkage treatment by development or the like after exposure to the hologram, thereby obtaining interference fringes. Although it is conceivable to change the interval, the developing process becomes complicated. Further, there is a problem that the reproduction wavelength cannot be changed depending on the recording material.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a holographic display device capable of easily changing the reproduction color of a hologram image according to the type of display in view of the above-mentioned conventional problems. .

[0016]

Means for Solving the Problems] holographic display device was made by the present invention for solving the above single
Multiple patterns recorded using laser light of one color
Transmission image hologram and transmission image hologram
Provided corresponding to each pattern recorded on the ram,
Is reproduction light of a specific emission wavelength band which is the same as the laser light.
And reproduction light of different specific emission wavelength bands
A plurality of types of reproduction light sources, and the plurality of patterns
Are recorded using a reference beam of equal angle of incidence,
The same emission wavelength band among the plurality of types of reproduction light sources
The reproduction light source records the reproduction light generated by the reproduction light source in the recording.
At the same angle as the incident angle of the reference light at the time.
And the emission wavelength band among the plurality of types of reproduction light sources.
The reproduction light source is different in that the wavelength of the reproduction light is the laser
When shorter than the light, the incident angle is smaller than the incident angle of the reference light.
In the case where the wavelength of the reproduction light is longer than the laser light,
At an incident angle greater than the incident angle of the reference light,
The generated reproduction light is incident on each of the patterns, and
Color change within the specified viewing angle range of the pattern
Is smaller than that at the same incident angle as the reference light.
It is characterized by being arranged so that.

In order to solve the above problems, a holographic display device according to the present invention is also provided with a single color laser.
A transmission image in which multiple patterns are recorded using the light
Dihologram and the transmission type image hologram.
Provided in correspondence with each of the patterns,
Reconstructed light of a specific emission wavelength band that is the same as light and different
Multiple types that generate reproduction light in specific emission wavelength bands
And a plurality of types of reproduction light sources,
Reproduction light generated by a reproduction light source is incident on the plurality of patterns.
Are arranged so that their incident angles are equal, and the plurality of
The turn is reproduced by the reproduction light of the same color as the laser light.
The pattern of the reproduction light source for reproducing the pattern is
Reference light incident at the same angle as the incident angle of the generated reproduction light
Are recorded using the plurality of patterns
Is reproduced with reproduction light of a shorter wavelength than the laser light
The pattern is larger than the angle of incidence of the reproduction light on the pattern
Incident at a different incident angle, and
The pattern reproduced with the reproduction light having a wavelength longer than the
Incident at an incident angle smaller than the incident angle of the reproduction light on the pattern
Using the reference light
Color change within the range of the predetermined viewing angle
It is characterized in that it is recorded so as to be smaller than the case of the incident angle .

The holographic display device according to claim 1 , wherein the laser beam is red.
Make sure that the reproduction light having a shorter wavelength than the laser light is orange.
Features .

[0019]

According to the holographic display device of the present invention , a single color laser beam is formed on a transmission type image hologram.
The laser beam recorded as a reference beam with the same incident angle
Of the number of patterns, the color of the laser light and the color of the reproduction light are the same.
For a pattern that is one, when the pattern is recorded
Angle of the reference light and the incident angle of the reproduction light to the pattern
And the color of the laser light and the color of the reproduction light
For different patterns, the wavelength of the reproduction light is
Reproduction at shorter incident angle than reference beam incident angle when shorter
The reproducing light generated by the light source is incident, and the wavelength of the reproducing light is
If it is longer than the light,
By inputting the reproduction light generated by the raw light source,
Color change within the specified viewing angle range of the pattern
Is smaller than when the incident angle is the same as that of the reference beam.
For recording multiple patterns.
Move the viewpoint while keeping the incident angles of illumination equal.
The angle dependence of the reproduction wavelength spectrum is unlikely to appear.
As a result , the hologram image is reproduced in the color of the reproduction light in a wide viewing range.

The holographic table according to claim 2
Depending on the configuration of the display device, a single
Laser light of the same color as the reference light with the same incident angle.
Multiple patterns that are recorded and reproduced with reproduction light having the same incident angle.
Pattern reproduced with reproduction light of the same color as the laser light.
The turn is incident at the same angle as the incident angle of the reproduction light
Recorded using a reference beam, but shorter than the laser beam
For patterns reproduced with the reproduction light of the wavelength ,
Each of the reference beams incident at an incident angle larger than the incident angle
Used by a laser beam that is reproduced with reproduction light having a wavelength longer than that of the laser light.
For turns, the incident angle is smaller than the incident angle of the reproduction light.
By using the incident reference light,
Reproduction of color change within a predetermined viewing angle range of the pattern
So that it is smaller than at the same angle of incidence as the light
The angle of incidence of the reproduction light on multiple patterns
Even if the viewpoint is moved while keeping the same, the reproduction wavelength spectrum
As a result , the hologram image is reproduced with the color of the reproduction light in a wide viewing range.

The holographic table according to claim 3,
Depending on the configuration of the display device,
The angle of incidence of the red reference beam remains the same, or
Is the incident angle of red and orange reproduction light on multiple patterns
Even if the viewpoint is moved while the
Even if the image is reproduced with orange reproduction light of a different color from the
The angle dependence of the long spectrum becomes difficult to appear, and as a result
The hologram image is reproduced with the color of the reproduction light in a wide viewing area
Become like

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, the same reference numerals are given to the same parts as those of the related art described above with reference to FIGS. 9 to 12, and the detailed description thereof will be omitted.

In the figure, a transmission type image hologram 2
2a is the same as the conventional one except for the final hologram recording optical system.

First, in the final hologram recording optical system shown in FIG. 1, the patterns 22a ₂ , 22a ₄ , 22a ₆ and 22a ₈ to be reproduced by the illuminated color filter 15 are set at a reference light incident angle θ ₅ = 50 °. , A pattern 22a to be reproduced by the red color filter 15
₁ , 22a ₃ , 22a ₅ , 22a ₇ and 22a _{9 at the} reference light incident angle θ ₅ = 45 ° and the final hologram 2
Record 2a with red laser.

Then, as shown in FIG. 2, the patterns 22a ₂ , 22a ₄ , 22a ₆ having the reference light incident angle θ ₅ = 50 °.
And 22a ₈ are light that has passed through the color filter 15 of the illuminated light, and the reproduced light incident angle θ is shifted by 5 ° from the reference light incident angle θ _5.
6 = 45 °, and patterns 22a ₁ , 22a ₃ , 22a ₅ , 22a ₇ and 22 with reference light incident angle θ ₅ = 45 °
a ₉ is light that has passed through the red color filter 15 and is reproduced at a reproduction light incident angle θ ₆ = 45 ° equal to the reference light incident angle θ ₅ .

Thus, the final hologram 22a
A color recording when the laser beam is red, the pattern 22a _2, 22a _4, 22a ₆ and 22a ₈ colors of the reproduction light is different in orange, pattern 22a _2, 22a _4, 22
Reference light incident angle θ when recording a ₆ and 22a _8
5 (= 50 °) to the patterns 22a ₂ , 22a ₄ , 22
reproducing light incidence angle when reproducing the a ₆ and 22a ₈ theta
_By making it larger than ₆ (= 45 °), the reproduction wavelength becomes shorter, so that the hologram images A ₂ , A ₄ , A ₆ and A ₈ can be reproduced with a lamp color which is the color of the color filter 15 in a wide viewing range. Also, the hologram images A ₁ , A ₃ , A ₅ ,
Since A ₇ and A ₉ is reproduced, the display effect can be improved by changing the reproduction colors depending on the type of alert.

The pattern 22 reproduced in red
a ₁ , 22a ₃ , 22a ₅ , 22a _7, and 22a ₉ , the incident angle θ ₆ of the reproduced light, and the pattern 22 reproduced by the light color
The reproduction light incident angle θ _{6 of} a ₂ , 22a ₄ , 22a ₆ and 22a ₈ can be kept equal, so that the process is simple,
Cost reduction becomes possible.

The amount by which the optimum reproduction wavelength is changed (shift width) can be controlled by the amount by which the reproduction light incident angle θ ₆ is changed from the reference light incident angle θ ₅ (θ ₆ −θ ₅ ).

Next, the reference light incident angle θ ₅ = 50 ° and the reproduced light incident angle θ ₆ = 45 for the patterns 22a ₂ , 22a ₄ , 22a ₆ and 22a ₈ to be reproduced with the above-mentioned light color.
The method of obtaining the angle by an experiment will be described with reference to FIG.

In this experiment, one of the oscillation wavelengths of a red laser (Kr (krypton) laser, 64
7 nm), and a silver halide film is used as a recording material. Also, the reference light incident angle θ ₅ = 50 °, the object light incident angle θ
₄ = 15 ° to record the final hologram 22a. As the reproducing light, the light of the incandescent bulb is used as a light color filter 15 (Tokyo Stage Illumination, polycolor N
o. Use the one passed through 33).

Table 1 shows changes in chromaticity and luminance when the viewpoint of the hologram reproduced image A is swung up and down when the reproduced light incident angle θ ₆ is 50 ° which is equal to the reference light incident angle θ ₅ .

[Table 1] Luminance is 100% of the measured value at the position that matches the playback conditions.
The other values are shown as relative values.

Next, changes in the luminance and chromaticity in the direction of the hologram image emission angle θ ₇ when the reproduction light incident angle θ ₆ is changed are shown in Table 2.
Shown in

[Table 2] Here, rather than 50 ° is equal to the reference beam incident angle theta ₅ peak recording intensity, there at 45 °, the reproduction light is orange (recording light red), optimum reproducing conditions (the most This is because the angle of “the diffraction efficiency is high and the image becomes brighter” changes in accordance with the color change.

Therefore, the brightest reproduction light incident angle θ
Table 6 shows changes in chromaticity and luminance when the viewpoint is swung up and down when ₆ = 45 °.

[Table 3] FIG. 5 shows the relationship between the color name of the color stimulus (color of light) and the chromaticity coordinates. As can be seen by comparing Tables 1 and 3 with reference to FIG. 5, when the reproduction light incident angle θ ₆ = 50 °, when the viewpoint is moved downward, the reproduction color clearly changes from the light color to red. Whereas the incident angle of the reproducing light θ ₆ = 4
When the angle is 5 °, there is a slight color change, but the tinge is maintained as a light color. In a normal vehicle display device, if the vertical viewing range is about ± 5 °, it can be visually recognized regardless of variations in the height of the driver's viewpoint.

From the above experimental results, it is found that the patterns 22a ₂ , 22a ₄ , 22a ₆ and 22a to be reproduced with light colors
It can be seen that with regard to ₈ , the reference light incident angle θ ₅ = 50 ° and the reproduction light incident angle θ ₆ = 45 °.

[0035] Next, a method for obtaining the theoretically optimal reference beam incident angle theta ₅ will be described with reference to FIG. The conditions are that the incident angle of the reproduction light θ ₆ = 45 ° and the emission angle of the hologram image θ ₇ = 1
5 °, desired reproduction wavelength = 590 nm (light color), hologram recording wavelength = 647 nm (red, one of Kr laser oscillation wavelengths), hologram medium average refractive index = 1.5, development / fixing processing, etc. There is no expansion or contraction of the film due to. For simplification, the reference light, the object light, and the reproduction light are assumed to be parallel lights.

In the figure, in a hologram in which interference occurs at an intersection angle of 2θ ₀ and a modulation such as a refractive index is recorded in a hologram emulsion layer, the layer interval 干 渉 of the interference fringes is

(Equation 1) It is represented by This is converted to another reproduction wavelength λ ₁ (value in the emulsion layer)
But the angle of incidence θ of the object beam during recording
_From the requirement that the emission angle θ _m of the reproduction light at the time of reproduction be equal to ₀ , θ _m = θ ₀ (2). Also, at this time, since the wavelengths of the reproduction light and the recording light are different even though θ _m = θ ₀ , the condition (phase matching condition) for the reproduction light to be diffracted by the hologram is sin θ _i + sin θ _m = λ ₁ / Λ (3) (θ _i : incident angle of reproduction light) is required. The hologram used in this method is
Assuming a thick hologram (volume hologram),
The Bragg condition exists for the reproduction wavelength and the reproduction angle, and the fact that the diffraction efficiency is reduced according to the deviation from the Bragg condition has been theoretically analyzed by KOGELNIK or the like. It is not advisable in the present method to change (e.g., record in red and reproduce in blue).

In addition, in addition to the above, the incident angle θ _{1 of the} reproduction light to the emulsion layer at the time of reproduction is 28.1 °, and the emission angle θ of the diffracted light.
₂ = 9.94 ° is determined, and from this condition, θ _i + θ _m = θ ₁ −θ ₂ (4). (1) Use ~ (4), first determine the theta _m. The procedure is as follows. Substituting equation (2) into equation (1),

(Equation 2) Substituting equation (5) into equation (3),

(Equation 3) Further, substituting equation (4),

(Equation 4) Here, α = θ ₁ −θ ₂ was set. Solving equation (7) gives

(Equation 5) Thus, θ _m (= θ ₀ ) is obtained. Now, what is finally required is the reference light incident angle θ ₅ , which is first obtained from the two equations of θ ₃ = 2θ ₀ + θ ₂ (9) n ₁ sin θ ₃ = n ₀ sin θ ₅ (10) ) is substituted into theta ₀ of the value (9) determined by the formula, using the law of refraction (10),
The reference beam incident angle theta ₅ may be obtained. Here,
n ₁ and n ₀ represent the average refractive index (= 1.5) of the hologram medium and the refractive index (= 1.0) of air, respectively.

First, the designed optical conditions, λ ₀ = 647 ×
10 ⁻⁹ /1.5=431.3×10 ⁻⁹ m, λ ₁ = 590
× 10 ^-9 /1.5=393.3×10 ^-9 m, θ ₁ = 2
Substituting 8.1 ° and θ ₂ = 9,94 ° into the equation (8), θ ₀
Is obtained, and θ _i is obtained from the equation (4), so that θ _i = 8.21 ° and θ ₀ = θ _m = 9.98 °. Further, these values are substituted into Expressions (9) and (10), and finally, the reference light incident angle θ ₅ = 48.4 °, which is a value substantially close to the experimental result.

[0039] Instead of changing the reference beam incident angle theta ₅ during final hologram 22a recording, reproduction light source 1
The hologram images A ₂ , A ₄ , A _6, and A ₈ can also be reproduced in a wide viewing range with the light of the color filter 15 by changing the reproduction light incident angle θ ₆ of No. ₃ .

Next, a plurality of transmission image holograms 2
A method of recording 2a on the same hologram emulsion will be described with reference to FIGS.

The recording optical system is the same as the conventional one. However, when the final hologram 22a is photographed, a portion other than one pattern is masked by the mask 31, so that the other portions are not affected by the hologram emulsion, so that the hologram emulsion is not affected. Enables hologram photography.

[0042] to move the position of the masking for each pattern, and by changing the reference beam incident angle theta ₅ for each pattern, it is possible to reproduce the respective patterns the same reproducing optical system in orange or red, The display quality and visibility of the alarm display of the display device can be improved.

In the final hologram 12a,
Since hologram recording is performed for each pattern, it is necessary to prepare a separate master hologram 121b for each pattern.

[0044]

As described above, in the holographic display device according to the present invention, when the color of the laser light and the color of the reproduction light are different from each other, the color of the laser light and the color of the reproduction light are the same. Even if the viewpoint is moved, the angle dependence of the reproduction wavelength spectrum is less likely to appear even if the viewpoint is moved, and as a result, the color of the reproduction light is wide in a wide viewing range. Since the hologram image is reproduced without any change, it is easy to change the incident angle of the reference light when recording the pattern and the incident angle of the reproduced light on the pattern. The hologram image can be reproduced in different colors.

[Brief description of the drawings]

FIG. 1 is a diagram showing a recording optical system of a transmission type image hologram according to the present invention.

FIG. 2 is a diagram showing a reproduction optical system of a transmission type image hologram according to the present invention.

FIG. 3 is a diagram showing a display surface of the present invention.

FIG. 4 is an explanatory diagram for obtaining an incident angle of reference light of the present invention by an experiment.

FIG. 5 is a diagram showing a relationship between a color name of a color stimulus (color of light) and chromaticity coordinates.

FIG. 6 is an explanatory diagram for theoretically obtaining a reference light incident angle according to the present invention.

FIG. 7 is an explanatory diagram for explaining a method of recording a plurality of transmission image holograms on the same hologram emulsion according to the present invention.

FIG. 8 is a front view of FIG. 7;

FIG. 9 is a side view showing a conventional holographic display device.

FIG. 10 is a diagram showing the display surface of FIG. 9;

FIG. 11 is a diagram showing a recording optical system of a transmission type image hologram.

FIG. 12 is a diagram showing a reproduction optical system of a transmission type image hologram.

[Explanation of symbols]

22a transmissive image hologram 22a ₁ ~22a ₉ pattern 13 reproduction light source theta ₅ reference beam incident angle theta ₆ reproduction light incident angle

Claims (3)

(57) [Claims] A plurality of patterns are formed by using a single color laser beam.
A transmission type image hologram is over emissions are recorded, each pattern recorded in the transmission type image hologram
Correspondingly provided, each having the same characteristics as the laser light.
Reproduced light in a constant emission wavelength band and a different specific emission wavelength band
And a plurality of types of reproduction light sources that respectively generate
The plurality of patterns use the reference light beams having the same incident angle.
It is recorded Te, the same of the emission wavelength ranges of the plurality of types of playback source
The reproduction light source records the reproduction light generated by the reproduction light source in the recording.
At the same angle as the incident angle of the reference light at the time.
Is location, to the difference in the emission wavelength band of the plurality of types of playback source
The reproducing light source has a wavelength of the reproducing light shorter than that of the laser light.
If the incident angle is smaller than the incident angle of the reference light,
When the wavelength of the reproduction light is longer than the laser light,
At an angle of incidence greater than the angle of incidence, the reproduction light source generates
Reproduction light is incident on each of the patterns, and
The color change within a predetermined viewing angle range of the pattern is
So that it is smaller than at the same incident angle as the reference beam.
A holographic display device which is arranged . 2. A method according to claim 1, wherein a plurality of patterns are formed using a single color laser beam.
A transmission type image hologram is over emissions are recorded, each pattern recorded in the transmission type image hologram
Correspondingly provided, each having the same characteristics as the laser light.
Reproduced light in a constant emission wavelength band and a different specific emission wavelength band
And a plurality of types of reproduction light sources that respectively generate
In addition, the plurality of types of reproduction light sources are generated by the reproduction light sources.
The incident angles at which the raw light enters the plurality of patterns are equal.
Arranged so that the same color reproduction of said laser beam of said plurality of patterns
The pattern reproduced by light is before the pattern is reproduced.
Enter at the same angle as the incident angle of the reproduction light generated by the reproduction light source.
Recorded using the emitted reference light, of the plurality of patterns having a shorter wavelength than the laser light.
The pattern reproduced by the reproduction light is the reproduction light
Incident at an angle of incidence greater than the angle of incidence of the plurality of patterns.
Reproduced with a reproduction light having a wavelength longer than that of the laser light.
Pattern is larger than the angle of incidence of the reproduction light on the pattern.
Reproduce using each reference beam incident at a small incident angle
Color change within the specified viewing angle range of the pattern
Is smaller than in the case of the same incident angle as the reproduction light.
Holographic display device characterized by being recorded as follows . 3. The method according to claim 2, wherein the laser light is red,
-The reproduction light having a shorter wavelength than the light is orange.
The holographic display device according to claim 1 .