JP2579131B2 - Dual image central high position stoplight using diffuse image - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to holograms for brake lights mounted in a high center of a vehicle, in particular holograms which effectively satisfy the required brightness and angular coverage, and exposures for recording such holograms. About technology.

[0002]

BACKGROUND OF THE INVENTION Current federal regulations require a central high mounted stoplight (CHMSL) in addition to a standard type of stoplight mounted on the rear of an automobile. High mounted stoplights are typically mounted on the rear window of the vehicle with the aim of maximizing the visibility of the vehicle's braking indicator to the driver of the vehicle following the vehicle being braked.

[0003]

High mounted stoplights generally include standard lenticular lenses, red filters, typically contained in a housing fixed adjacent to the top or bottom of the rear window of the vehicle. The illumination is configured as an incandescent lamp and a reflector. However, the large housing partially obstructs the driver's rear view,
In addition, the design of the vehicle is limited. The center high mounted stoplight is also integrated into the body parts of the vehicle, such as the rear deck, spoiler, roof, etc., which substantially alleviates or eliminates rear visibility problems to some extent. However, such stoplights are complex and limit the design of the vehicle.

[0004] Holographic mid-high brake lights have also been developed to effectively satisfy brake light regulations. A consideration for the use of holograms for holographic mid-high mounted stoplights is that it is desirable to obtain an output having the appearance of a lenticular lens similar to that provided by a normal stoplight. Another consideration for the use of holograms for holographic mid-high mounted stoplights is the complexity of using the minimum power reconstructed light source while meeting government-specified brightness and angular coverage requirements. is there. Luminance and angular coverage requirements are quantitative issues that limit luminance to a generally defined central angular area,
And qualitative issues requiring visibility over horizontal angle fields that are larger than the horizontal component of the defined central angle field. In essence, regulation requires a bright area approximately in the center of the required angular field of coverage.

Accordingly, it would be advantageous to provide a holographic mid-high mounted stoplight that provides an output having an appearance similar to that of a lenticular lens of a normal stoplight. It is another object of the present invention to provide a holographic mid-high stoplight that easily meets government-specified brightness and angular coverage requirements while using a minimum power reconstructed light source.

[0006]

SUMMARY OF THE INVENTION These and other advantages include a light source for providing a reconstructed beam, and each hologram cell having a diffuse illumination in a first predetermined angular field according to the diffraction of a portion of the reconstructed beam. A first array of non-overlapping hologram cells and non-hologram cells emitting a non-overlapping hologram cell, each hologram cell emitting diffuse illumination in a second predetermined angular field according to diffraction of a portion of the reconstructed beam And a second array of non-hologram cells. The first array of cells is arranged in a first predetermined pattern to produce a pattern of bright and dim areas in a first angular field according to diffraction by the hologram cells of the first array; Is arranged in a second predetermined pattern to generate a pattern of bright and dim areas in a second angular field according to diffraction by the hologram cells of the second array; A portion of the reconstructed beam thereby diffracted by the holographic lenses of the first and second holograms forms a stoplight illumination.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS The various advantages of the present invention will become apparent to one of ordinary skill in the art upon review of the following specification and upon reference to the accompanying drawings. Referring to FIG. 1, a central high mounted stoplight system including a hologram device 20 and an illumination light source 30 is shown. The hologram device 20 includes first and second stacked volume transmission holograms 31, 32, further described herein, secured to the inside surface of the rear window 211 of the vehicle. Alternatively, the hologram device 20 can be fixed to a separate substrate suitably located near the rear window 211. The illumination light source 30 deviates from the rear view angle of the driver in front of the hologram device 20 and, for example, a rear window of a car.
Mounted under a substantially horizontal rear deck adjacent to the lower portion of 211, the reconstructed beam illuminates the volume holograms 31, 32 of the hologram device 20.

The volume hologram of the hologram device 20
31 and 32 are configured to provide a suitable composite image observable from behind the vehicle over a suitable vertical and horizontal field of view when illuminated by the illumination light source 30. In the following, the volume holograms 31, 32 will be described in terms of their angular coverage (ie, the angular fields where their light output can be observed) and their configuration. Note that, for ease of relevance, the angle field is generally related to the configuration of the hologram. As used herein, the terms angular field and angular coverage refer to all angular regions of space where light is diffracted by a hologram cell,
Therefore, it means an angle region where diffracted light can be observed. It should be understood that the angular coverage limits the angular field over which the light output of the hologram can be observed, so that the diffracted output of the hologram is limited to its angular coverage and some additional blurring. It is. The holograms of the hologram device are configured to produce diffracted illumination observable from behind a vehicle in which they are located and their angular fields extend rearward from the vehicle.

The illumination light source 30 includes an incandescent lamp 15 such as a quartz halogen bulb, a reflector 17 which cooperates with a filament of the incandescent lamp 15 to supply a reconstructed beam to the hologram device 20, and
It includes a high-pass filter 19 having a cut-off wavelength of 600 nanometers (nm). In the example shown, the reflector 17 includes a parabolic reflector that produces a substantially collimated reconstructed beam in cooperation with the filament of the incandescent lamp 15. As a result of the wavelength-dependent sensitivity of human vision, the image provided by the hologram of the hologram device is perceived as red,
Distinct peak intensities are between about 610 and 620 nm.
The incandescent light 15 is connected to a brake light energizing circuit of the vehicle so as to be excited when a brake pedal is depressed.

Referring to FIG. 2, the Federal Motor Vehicle Safety Standard N
o.108 ("MVSS 108") versus luminance (in candela) versus (a) 10 ° upwards and 5 ° downwards with respect to a central horizontal plane H through the center of CHMSL, and (b) CHMSL. A graph showing the angle field requirements of the high center mounted stoplights for a center angle field defined as 10 ° each left and right with respect to a central vertical plane V including the longitudinal axis of the vehicle through the center of FIG. The numbers in the graph indicate the minimum brightness at these angular positions in candela, with the overall angular field being up to 160 candela at any given angular position. In addition to the above quantitative requirement, referred to herein as the "central angle field requirement", the stoplight is within a central horizontal plane (i.e., two horizontal angle regions that are mirror images of each other) extending 45 degrees from either side of the central vertical plane. There are qualitative requirements that are observable at To illustrate, this qualitative requirement can be interpreted as requiring about 1 candela of brightness. From both sides of the central vertical plane
Such a requirement for visibility over a central horizontal plane over a range of 45 ° is referred to herein as a wide angle horizontal requirement.

According to the present invention, the holograms 31, 32 are configured to diffract the diffused light into different angular fields according to the illumination by the reconstructed beam provided by the illumination light source, wherein the diffracted light generated by each hologram is provided. Includes (a) bright areas and (b) dim areas arranged in a recognizable pattern such as LOGO or letters and numbers.

Referring to FIG. 3, a hologram 31 prior to lamination with another hologram 32 is schematically shown, the surface shown being the rear-facing surface when installed in a motor vehicle. The hologram includes a non-overlapping adjacent hologram of the same size and a linear array or grid of non-hologram cells or facets C (i, j).
Each hologram cell, shown as an unshaded square in FIG. 3, has a diffracted diffusion with the desired angular coverage that is the same for all facets C (i, j) that include the hologram cell. Generate output. That is, the diffuse output of each holographic cell can be observed from within a predetermined angular space, and such an angular space is substantially the same for each hologram cell of the first hologram 31. Each non-hologram cell, shown as a hatched square in FIG. 3, does not contain a hologram and contains a transparent region that does not diffract the reconstructed illumination incident thereon.

In accordance with the present invention, the hologram and non-hologram cells of the hologram of FIG. 3 are patterned so as to produce a pattern of recognizable bright and dim areas, eg, LOGO, when the hologram is illuminated by the reconstructed beam. It is arranged in. Light areas are created by hologram cells and dark areas are created by non-hologram cells. Alternatively, the dim hologram cell can be replaced with the non-hologram cell of hologram 31 of FIG. 3, where the bright and dim hologram cells of the hologram of FIG. When arranged, they are arranged in a pattern to produce a pattern of recognizable light and dark areas, for example LOGO.
Bright areas are created by bright hologram cells,
Dim areas are created by dim hologram cells. To illustrate, each dim hologram cell contains a halftone hologram composed of an array of small holograms and non-hologram regions. Referring to the drawing,
The top row C (1, j) of the cell constitutes the top of the hologram 31 when it is located in the installed hologram device of the CHMSL system, whereby each row of cells is aligned substantially horizontally. . Consistent with such a direction,
The parallel edges of the cells, which are aligned substantially horizontally when installed in a car, are called the upper and lower edges, with the upper edge closest to the top of the figure and the closest to the top of the rear window when installed. Also, the parallel edges of the cell that are perpendicular to the upper and lower edges are called side edges. Cell C (i, j) is the same size, the width of the cell is measured along the top or bottom edge, while the height of the cell is measured along both side edges.

Referring to FIG. 4, a hologram 32 prior to lamination with another hologram 31 is schematically shown, the surface shown being the surface facing the outside of the vehicle when installed. The hologram is composed of non-overlapping adjacent holograms of the same size and non-hologram cells or facets F
Includes a (i, j) linear array or grid. Each hologram cell, shown as an unshaded square in FIG. 4, is diffracted with the desired angular coverage that is the same for all facets F (i, j) that make up the hologram cell. Generate output. That is, the diffuse output of each holographic cell is observable from within a predetermined angular space, and such a predetermined angular space is substantially the same for each hologram cell of the second hologram 32. . Each hologram cell shown as a hatched square in FIG. 4 includes a transparent region that does not include a hologram cell. According to the present invention, the hologram cell and the non-hologram cell of the hologram of FIG.
When the hologram is illuminated by the reconstructed beam,
Recognizable patterns of bright and dark areas, for example L
It is arranged in a pattern to generate OGO. Bright areas are created by hologram cells and dark areas are created by non-hologram cells. Instead,
A dim hologram cell can be substituted for the non-hologram cell of hologram 32 of FIG. 4, in which case FIG.
The bright and dim hologram cells of the hologram are arranged in a pattern such that when the hologram is illuminated by the reconstructed beam, it produces a pattern of recognizable bright and dim areas, eg, LOGO. Bright areas are created by bright hologram cells, and dim areas are created by dim hologram cells. To illustrate, each dim hologram cell is:
It includes a halftone hologram composed of an array of small holograms and non-hologram regions. Referring to the drawings, the top row of hologram cells F (1, j) includes the top of hologram 32 when it is located in the installed hologram device of the CHMSL system, whereby each row of hologram cells is Aligned almost horizontally.
Consistent with such a direction, the parallel edges of cells that are aligned substantially horizontally when installed in a car are called the upper and lower edges, with the upper edge closest to the top of the figure and when installed Closest to the top of the rear window. Also, the parallel edges of the cell that are perpendicular to the upper and lower edges are called side edges. Cell F (i,
j) is the same size, the width of the cell is measured along the top or bottom edge, while the height of the cell is measured along both side edges. To illustrate, each hologram and non-hologram (or dim hologram) cell pattern of the first and second holograms can be the inverse of each other, and the light and dark (or dim) areas in one hologram Are the dark (or dim) and bright areas, respectively, in the other hologram. For example, LOGO formed by dark (or dim) areas in one hologram can be formed by bright areas in another hologram.

In accordance with the present invention, each hologram facet or cell of one of the holograms 31, 32 has an upper and lower limit of 10 ° above and 5 ° below the central solid angle region shown in FIG. It is configured to diffract diffused light into a solid angle having a lateral limit of 10 ° from both sides of a vertical plane parallel to the vertical axis. In other words, the solid angle region is centered on a line passing through the center of the hologram cell, is approximately 2.5 ° above a horizontal plane, and lies in a vertical plane parallel to the longitudinal axis of the vehicle. Each hologram cell of the other hologram is configured to diffract the diffused light into two horizontal regions on either side of the central solid angle region such that the combination of both holograms satisfies the horizontal wide angle requirement. Such two horizontal regions are often referred to as peripheral horizontal angle regions.

Although the angular coverage of the hologram is described in terms of exact angles, the actual coverage typically slightly exceeds the angular coverage configured due to the blur created by the non-ideal reconstruction beam. You should understand that. Thus, the two hologram cells are configured to have adjacent non-overlapping angular coverage without gaps in coverage, but in practice there is overlap in coverage due to blurring .

For ease of reference, a hologram that diffracts the diffused light into the central solid angle region is often called a narrow angle hologram, while the other hologram is often called a wide angle hologram. Each hologram cell of a narrow-angle hologram produces an image of a diffuser whose output is generally limited to a central solid angle region, while each hologram cell of a wide-angle hologram outputs a horizontal Generates an image of the diffuser confined to the surrounding area of. According to the present invention, the hologram cells of the first hologram 31 each diffract light into substantially the same predetermined angular field, and the cells of the second hologram 32 have predetermined angles of the hologram cells of the hologram 31. Diffract the light into each substantially the same predetermined angular field different from the field. Illustratively, the holograms 31 and 32 have substantially the same cell size and have substantially the same array of cells with substantially the same cell arrangement. According to yet another example, holograms 31, 32
Cell array, each cell in the hologram 31 is a hologram
The holograms are aligned when stacked so that they have the corresponding cells in 32 and the corresponding cell boundaries are aligned.

The number of cells in each hologram 31, 32 and the arrangement of cells in each hologram depends on the overall shape and size of the overall format of each hologram, as well as the size of the selected cell. , Cell size, appearance,
The selection is made in consideration of factors such as the nature of the pattern in the bright and dark areas (or dim areas) and the ease of generation. In addition, taking into account the dimensions of the hologram cell, the size of the cell is not only tailored to the particular vehicle design, but also to obtain a suitable resolution of the pattern of recognizable bright and dim areas (or dark areas). Can be

For the example in which the first hologram 31 comprises a wide-angle hologram and the second hologram 32 comprises a narrow-angle hologram, each hologram cell F of the second hologram 32
Defines a solid angle region in which each hologram cell F upon reconstruction has an upper and lower limit of 10 ° above and 5 ° below the horizontal, and a lateral limit of 10 ° from both sides of a vertical plane parallel to the longitudinal axis of the vehicle. The image is configured to generate an image of a diffuser that emits light during the included angular field.
Furthermore, for such an example, each hologram cell C of the first hologram 31 emits diffused light during reconstruction in an angular field consisting of two peripheral angle regions on both sides of the central solid angle region. The diffuser is configured to generate an image of the diffuser. For example, both peripheral solid angle regions have upper and lower limits of about 5 ° above and about 5 ° below the horizontal. One peripheral angle region is between 10 ° and 45 ° on one side of a vertical plane parallel to the longitudinal axis of the vehicle, while another angle region is between 10 ° and 45 ° on the other side of the vertical plane.

As described in further detail herein, the angular field from which the hologram cell emits light is:
It is controlled by the structure of the hologram cell. Referring to FIGS. 5A and 5B, for example, a reflection narrow-angle hologram in which the second hologram 32 includes a narrow-angle hologram oriented in an installed hologram device, with the angular field of the diffracted output of the cell. A side view and a plan view seen from above of the cell F are schematically shown. As shown in FIG. 5A, the upper and lower boundaries of the angle range of the diffracted output are (1) 10 ° above the horizontal plane.
(2) a lower plane BP extending from the lower edge of the hologram cell at a vertical angle of 5 ° below the horizontal plane. The upper plane TP and the lower plane BP are
Such a plane is indicated by a line in FIG. As shown in FIG. 5B, the lateral boundary of the output angle field extends from the left edge of the hologram cell at a horizontal angle of 10 ° to the left from a vertical plane parallel to the vehicle centerline. 10 ° to the right from a vertical plane parallel to the center line of the car
Right plane RP extending from the right edge of the hologram cell at a horizontal angle of Left plane LP and right plane RP
Are indicated by lines in FIG. 5B because such a plane is orthogonal to the plane of the drawing.

6A and 6B for a specific example where the second hologram 32 comprises a narrow angle hologram and the first hologram 31 comprises a wide angle hologram.
A side view and a top plan view of the hologram cell C of the hologram 31 oriented in the installed hologram device are shown, along with the left and right angle ranges of the diffracted output. The lateral boundary of the output angle region diffracted to the left is (1) 45 ° to the left from a vertical plane parallel to the center line of the car
And (2) a plane LP ′ 10 ° to the left from a vertical plane parallel to the center line of the vehicle. The lateral boundaries of the right output beam BR are (1) a right plane RP extending from the right edge of the hologram cell at an angle of 45 ° from the vertical plane, and (2) a right plane from the vertical plane passing through the center of the hologram cell.
It is determined by the plane RP 'of 10 °. Plane LP, LP
′, RP and RP ′ are indicated by lines in FIG. 6B because such a plane is orthogonal to the plane of the drawing. As further described herein, planes LP, L
P ′, RP and RP ′ are determined by appropriate masking of the objective beam used to construct the hologram cell C.

For the particular example in which the first hologram 31 is closest to the reconstructed light source 30 and includes a wide-angle hologram, most of the reconstructed illumination will produce a narrow-angle hologram that needs to provide a significantly brighter output. Wide-angle holograms must be less efficient than others to allow them to pass. For example, a wide-angle hologram can have about 30-40% efficiency for ideal reconstructed illumination, and a narrow-angle hologram can have 90% or more efficiency for ideal reconstructed illumination. is there.

If the wide-angle hologram is configured with relatively high efficiency, the second hologram 32 must be configured as a wide-angle hologram, the first hologram must be configured as a narrow-angle hologram, Both holograms must have a relatively high efficiency of 90% or more of the ideal reconstructed illumination. These conditions arise from the requirement that the diffracted light output of the narrow angle hologram must be significantly greater than the diffracted light output of the wide angle hologram. By making the narrow-angle hologram relatively efficient and placing it closest to the reconstructed light source, the narrow-angle hologram can meet the brightness requirements by diffracting most of the reconstructed illumination. Because most of the reconstructed illumination is diffracted by the narrow-angle hologram, the available reconstructed illumination for the wide-angle hologram is significantly reduced,
It must also have a relatively high efficiency of over 90% of the ideal reconstructed illumination.

With respect to the order of the narrow and wide angle holograms for both structures described above, it is pointed out that losses due to re-diffraction must be taken into account for the structure in which the wide and narrow angle hologram cells are superimposed. Should.

In a structure where the wide-angle hologram cell and the narrow-angle hologram cell are superimposed such that the wide-angle hologram is closest to the reconstructed illumination source, the limited overlap of the angular coverage of the narrow-angle and wide-angle holograms, and such a structure As a result of the relatively low efficiency of the wide angle hologram with respect to, only a small amount of diffracted light in the central solid angle region is incident on the narrow angle hologram. Therefore, only a small amount of diffracted light is diffracted again by the narrow-angle hologram.

In a structure in which a narrow-angle hologram cell and a wide-angle hologram cell are superimposed, and the narrow-angle hologram is closest to the reconstructed illumination light source, a large amount of diffracted light in the narrow-angle central region defined by the MVSS 108 is converted to a wide-angle hologram. Incident on. However, because the wide angle hologram is configured to reduce the amount of light, it diffracts into the central angle region, and the amount of light diffracted by the narrow angle hologram is reduced.

The first and second holograms 31, 32 are:
The non-hologram cell is formed from a suitable hologram recording layer where the non-hologram cell is formed by exposing the area to contain the non-hologram cell to non-coherent light. For example, a thin film type mask having a transparent region defining a non-hologram cell is positioned adjacent to the hologram recording layer and index matched to it by a thin layer of fluid index matched therewith. Thereafter, the mask is illuminated with non-coherent light so as to reduce the sensitivity of the areas of the hologram recording layer that are not covered by the mask so that holograms cannot be formed there. afterwards,
The hologram cell is formed by hologram formation exposure. All hologram cells in the hologram can be exposed to diffract equally, or have different diffraction properties according to specific requirements such as the curvature of the installed hologram device or the non-collimation of the illumination light source Can be exposed as follows. Further, the hologram cells in the hologram can be exposed one or several at a time.

Referring to FIG. 7, an example of an exposure setting for recording a hologram cell of a narrow-angle hologram by a series of exposures where each exposure can expose a plurality of non-adjacent hologram cells in one row. Have been. The exposure setting includes a horizontal linear array 53 of plano-convex spherical lenses 53a that receives the masked output of the diffuser screen 52 illuminated by the collimated beam CB1. The diffusion screen 52 is displaced by the plano-convex spherical lens 53a by the focal length of such a lens, which is schematically shown in FIG. 8 when viewed from the output side of the diffusion screen 52. The output of the diffusion screen 52 is shown in FIG.
Except for a horizontal linear array of transparent regions 54, as schematically shown in FIG. The curved surface of the plano-convex spherical lens 53a faces the diffusing screen as shown in FIG. The mask transparent area 54a is aligned with the spherical lens 53a so as to have the same center-to-center spacing S1 equal to the integer number of adjacent cells to be formed in the hologram recording layer being exposed. For ease of explanation, the masked output of diffuser screen 52 and the output of plano-convex spherical lens 53a are represented by centerlines.

Further, the exposure setting is a CHMSL hologram.
Except for a transparent area 51a having the same size as the cells 31 and 32 and being evenly spaced apart, it is opaque and has a plano-convex lens 53a.
The plano-convex spherical lens 53 has the same center-to-center spacing S1 as
Use a thin film type mask 51 as schematically shown in FIG. 10 aligned with a. The number of transparent areas is the same as that of the plano-convex lens 53a. The horizontal center distance S1 between the plano-convex spherical lens, the mask transparent region 54a and the plano-convex spherical lens 53a is such that the dimension of the mask transparent region is MVSS 1
Must be sufficient to match the size or f-number of each planospheric lens selected to produce an objective beam OB having an angular variance corresponding to the central angular area defined by 08. In particular, since the diffuser 52 is separated from the plano-convex lens by the focal length of such a lens, each lens collimates the output of each point light on the portion of the diffusion screen not covered by the corresponding mask transparent area 54a, Thus, the size of the mask and the f-number of the lens, which can be further controlled by masking, determine the angular dispersion of the objective beam OB. The distance between the hologram recording film and the plano-convex lens is selected such that each mask transparent area 53a is completely filled with light from the corresponding plano-convex lens, and the output of the plano-convex lens in the area where the hologram recording layer is not covered. Are avoided.

As shown particularly in FIG. 7, the holographic recording device 60 is arranged below the exposure mask device 50. The holographic recording device 60 has a glass substrate 63 and a glass substrate
The hologram recording layer 61 disposed on the hologram recording layer 61, the thin covering layer 65 disposed on the hologram recording layer 61, and the optical absorption that is adjacent to the lower portion of the glass substrate 63 and whose refractive index is matched by the refractive index-matched fluid layer 73. It is composed of a layer 71. The exposure mask device 50 includes a mask 51 and a mask supporting base 55. Holographic recording device 60 and exposure mask device 50
Are positioned opposite each other on an exposure mask 51 and a thin cover layer 65 separated by a very thin layer of refractive index matching fluid 57.

To illustrate, the holographic recording device 60 has a C
The region corresponding to the cell of the HMSL hologram can be moved, for example, by a computer drive motor, so that the region corresponding to the cell of the HMSL hologram can be selectively positioned below the mask transparent region 51a. In order to limit illumination to cells not covered by the mask transparent area, the mask and mask base are only exposed to constituent illumination of the portion of the hologram recording layer below the mask transparent area 51a for all exposure positions of the hologram recording layer. The top cover is secured to the opening of the opaque top cover of the normal oil gate groove 69, which is large enough to ensure exposure.

The reference beam for exposure includes a portion of the collimated beam CB2 whose angle is based on the illustrated example of CHMSL illuminated from below as shown in FIG. The upper part of the CHMSL hologram corresponds to the left edge of the hologram recording layer orthogonal to the plane of the drawing.

The exposure of the cells not covered by the mask transparent area 51a is performed by positioning the holographic recording apparatus so that the area of the hologram recording layer corresponding to the cell below the mask transparent area is arranged, and through a flat spherical lens array. This is done by illuminating and illuminating the unmasked cells with the collimated beam CB2. As a result of the initially masked and reduced sensitivity exposure to form non-hologram cells, holograms can be formed only in those areas of the hologram recording layer that are intended to be hologram cells.

To illustrate, rows of cells are sequentially exposed and a subset of the set of cells that ultimately form a row within each row of cells can be sequentially exposed to constituent illumination. Thus, for the particular example where the spacing between the mask transparent regions is three cells, for each row i, the holographic recorder will expose a first cell subset consisting of cells C (i, j). Is moved, where j is 1,4
Equal to 7, 10, etc. After the holographic recorder has been installed, such a first subset of cells is exposed with constituent illumination. After that, the holographic recording device reads the cell C (i,
j) is moved to expose a second cell subset consisting of j), where j equals 2, 5, 8, 11, etc. After the holographic recorder has been installed, such a second subset of cells is exposed with constituent illumination. The steps of indexing the holographic recorder by one cell in a row and exposing the cells exposed by the constituent illumination are repeated when it becomes necessary to expose all cells in a given row to holographic constituent illumination. You. Although all cell areas in a given row are illuminated with hologram-configured illumination, holograms can be formed only in cell areas where sensitivity has not been reduced. Depending on the number of cells in one row, the number of transparent areas in the mask, and the spacing between mask transparent areas, at positions indexed after one or more in one row, the number of exposed cells is the first It should be understood that it is likely to be less than the number of exposed cells at the indexed location.

In the above process in which the hologram recording layer is moved with respect to the mask, the objective beam-forming lens is stationary, the reference beam comprises a collimated beam, and each cell has such a reference beam angle in the plane of the cell. Exposed at substantially the same reference beam incidence angle formed between the beam and the line passing through the center of the cell, parallel to the central axis of the collimated beam CB2. Since an uncollimated reference beam shape is used, the reference beam angle is the same for all cells, but the reconstructed beam angle for the corresponding uncollimated reconstructed beam shape is not the same for all cells, resulting in This reduces the brightness when constituted by each reference beam having substantially the same angle of incidence as In order to more accurately emulate the reproduction light source, the reference beam incidence angle is determined, for example, by Smith et al. In another U.S. patent application Ser. No. 07 / 995,117.
Specification (filed on December 22, 1992, “MODIFIED TECHNIQUE
FOR FABRICATING LOW NOISE FLOODLIT CHMSL HOLOGRAM
S "), it can be varied for each row of cells such that the reference beam incidence angle for each cell more closely approximates the intended reconstructed incidence angle for that cell. it can.

Referring to FIG. 11, there is illustrated an exposure setting for recording a wide-angle hologram by a series of exposures, each exposure exposing a plurality of uniformly spaced non-adjacent cells in a row. . The exposure system of FIG. 10 is similar to the exposure system of FIG. 7, and the same elements are denoted by the same reference numerals. The difference between the exposure systems is that a uniform diffusion screen 152 illuminated by the collimated beam CB1 and whose output is masked by a thin-film type mask 154, and as seen from the output side of the mask, as shown in FIG. Also mask 154 and baffle
13 includes a baffle 156 as shown in FIG. Mask 154
Is a mask transparent area 1 separated by an opaque area 154b having a center-to-center spacing of S2 equal to an integer number of adjacent cells to be formed in the hologram recording layer being exposed.
Opaque except for the horizontal linear array of 54a, the baffle 156 is centrally located in the mask transparent area 154a in alignment with the optical axis of the collimated beam CB1.
For ease of explanation, the masked output of the uniform diffusion screen 152 is shown with a center line.

The exposure setting of FIG. 11 also uses a thin-film type mask 151, shown schematically in FIG. 14, which is uniformly spaced as large as each cell of the wide-angle hologram. It is opaque except for the mask transparent area 151a and is aligned with the opaque area 154b of the mask 154 so as to have the same center-to-center spacing S2 as the opaque area 154b. The number of mask transparent areas 151a is
It is the same as the number of b. Mask 154 and baffle 156
Cooperate to generate an objective beam that illuminates each of the mask transparent areas 151a adjacent to the hologram recording layer. Each objective beam effectively contains a beam that is scattered horizontally and vertically on either side of the central shadow area. The angular dispersion of each objective beam is determined by the mask transparent area of mask 154.
Horizontal center-to-center spacing between 154a, mask transparent area 1
Controlled by the height of 54a and the distance of the mask 154 and the uniform diffusion screen from the mask transparent area 151a adjacent to the hologram recording layer, the angular range of the shadow area is the width of the intervening opaque area 154b of the mask 154. ,
And the distance of the mask 154 and the uniform diffusion screen. The angular field of each objective beam is controlled to correspond to the two horizontal regions on either side of the central solid angle region, especially so that the combination of both holograms satisfies the wide horizontal angle requirement.

To illustrate, the cell rows of the wide-angle hologram formed according to the exposure settings of FIG. 11 are exposed in a manner indexed as described above with respect to the exposure settings of FIG.

Further in accordance with the present invention, a narrow-angle hologram master and a wide-angle hologram master are formed by the exposure systems of FIGS. 7 and 11, respectively, after which such masters are mounted on the holographic center high mounted stoplight of FIG. Used to form holograms 31,32. The narrow-angle hologram master and the wide-angle hologram master can be copied separately to form separate copies of each. Alternatively, they can be stacked and copied to form a composite hologram. In either case, the efficiency of the narrow-angle hologram master and the wide-angle hologram master formed according to the exposure systems of FIGS. 7 and 10 must be selected so that the hologram copy provides the desired efficiency.

Referring specifically to FIG. 15, FIG. 7 and FIG.
1 schematically illustrates a copying system for forming a hologram copy from a hologram master formed according to one exposure system. The reproduction system includes a master hologram 111, an adjacent hologram recording layer 113 located a minimum distance from the master hologram, and an intervening thin layer 115 of index matching fluid. The master hologram is supported by a glass substrate 117, while the hologram recording layer 113 is supported by an opaque back support layer 119. When used, the master hologram 11
The replicated reference beam RB emulating the reference beam used to construct
Is directed towards the glass substrate at an angle that produces a beam angle suitable for reconstruction of Copy reference beam is glass substrate 117
And is partially diffracted by the master hologram 111. Diffracted and undiffracted light from the master hologram interferes in the hologram recording layer and forms a hologram copy.

In order to maximize the efficiency of narrow-angle hologram copying, the narrow-angle hologram used as the narrow-angle hologram master provides a one-to-one beam rate, for example, for the Dupont HRF600 photopolymerized hologram recording layer. Must have 50% efficiency. About 30%
For wide-angle hologram copies with efficiencies in the range of 4040%, the wide-angle hologram used as the wide-angle hologram master for the structure where the wide-angle hologram is closest to the reconstructed light source 30 is, for example, a DuPont HRF600 photopolymerized hologram. It should have an efficiency in the range of about 10% to 20% for the recording layer. For a wide-angle hologram copy with an efficiency of 90% or more, for the structure where the narrow-angle hologram is closest to the reconstructed light source 30, the wide-angle hologram used as the wide-angle hologram master is:
For example, it must have an efficiency in the range of about 50% for a DuPont HRF600 photopolymerized hologram recording layer.

As previously described, the narrow-angle hologram master and the wide-angle hologram master can be copied separately to form separate respective copies. Alternatively, they can be stacked and copied to form a composite hologram copy that is used in place of the first and second holograms 31,32. The copying system of FIG. 5 can be used to create a composite hologram copy by using a stack of a narrow angle hologram master and a wide angle hologram master as the hologram master 111. In the composite copy, the narrow-angle hologram cell and the wide-angle hologram cell are superimposed on the hologram copy layer.

When forming a composite copy, the diffraction light from one hologram master may interfere with the diffraction light from another hologram master, producing a cross-modulated noise hologram, and therefore a narrow angle and a wide angle. The relative efficiency of the angle hologram master must be properly selected. This problem can be mitigated by reducing the diffraction output of both hologram masters, including the objective beam in the structure of the composite hologram copy. For example, about 25% for a DuPont HRF600 photopolymerized holographic recording layer.
A narrow-angle hologram master efficiency of 5% and a wide-angle hologram master efficiency of about 5% significantly reduce cross-modulation noise holograms, while minimizing the loss of efficiency in the desired diffraction direction of the copy. In structures where the bright and dark (or dim) cell patterns of the narrow-angle hologram cell pattern are the opposite of the bright and dark (or dim) cell patterns of the wide-angle hologram, the cross-modulation noise hologram is substantially absent. , Each hologram master can have about 50% efficiency.

In the above copying process, each master hologram contained the desired pattern of holograms and non-hologram cells. As a separate step to the copying process where separate narrow and wide angle hologram copies are formed from separate hologram masters, copy holograms pre-expose the holographic recording layer to define the desired non-hologram cells, and then All cells can be formed by copying a suitable hologram master, which is a hologram cell. In this way, the hologram is formed only in the area of the holographic recording layer where the hologram cell is intended to be formed, since the non-hologram cell was defined by reducing the sensitivity of the pre-exposure.

Although the hologram device of the present invention has been described above with reference to a hologram providing an image without distortion for illustrative purposes, the present invention also provides a hologram providing a pseudoscopic image. Is also applicable. For example, one or both of the holograms 31 and 32 of the hologram device may be positioned 180 degrees about a horizontal axis such that the original top of the hologram is at the bottom and the hologram surface initially facing the inside of the car faces the outside of the car. ° can be rotated. Each cell of the hologram rotated in this manner produces an image of a point or line light source located behind the hologram (i.e., facing the back of the car), and the focused beam is masked by the cell boundaries. The horizontal and vertical variances are determined as if they were done.

According to another aspect of the present invention, a single narrow-angle hologram can be used for the holographic device of the holographic mid-high mounted stoplight of FIG. 1, in which case the coverage of the peripheral area is increased. Is provided by scattered illumination.

The above is a description of a hologram center high mounted stoplight that meets government regulations for brightness and angular coverage requirements while minimizing the required power. The hologram structure of the hologram center high mounted brake light of the present invention can be configured to produce a lenticular lens appearance similar to a normal brake light, with a separate hologram layer for each hologram copy layer. It can be easily adapted for efficient production by copying, or copying multiple hologram layers to a single layer hologram copy.

The foregoing is a description and illustration of particular embodiments of the present invention, and those skilled in the art will appreciate that various modifications and alterations can be made without departing from the scope of the present invention as defined by the appended claims. It is possible to make changes.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a holographic vehicle center-high mounted stoplight according to the present invention.

FIG. 2 is a luminance distribution graph showing the vertical and horizontal requirements for a center high mounted stoplight in candela.

3 is a schematic diagram showing the configuration of one cell of the hologram of the holographic brake light mounted at the holographic center high position in FIG. 1;

FIG. 4 is a schematic diagram showing the configuration of the other cell of the hologram of the brake light mounted at the holographic center high position in FIG. 1;

5A and 5B are a side view and a plan view showing a reproduction characteristic of each hologram cell of the hologram of FIG.

6A and 6B are a side view and a plan view showing a reproduction characteristic of each hologram cell of the hologram of FIG.

FIG. 7 is a schematic diagram showing one embodiment of an exposure system for forming the CHMSL hologram of FIG. 3;

8 is a schematic diagram illustrating one embodiment of a spherical lens array used in the exposure setting of FIG. 7 to construct the hologram of FIG. 3;

9 is a schematic diagram illustrating one embodiment of a mask used to mask the output of a diffusion screen at the exposure setting of FIG. 7 to construct the hologram of FIG. 3;

10 is a schematic diagram illustrating one embodiment of a mask used to define the area of the hologram cell in the exposure setting of FIG. 7 to construct the hologram of FIG. 3;

FIG. 11 is a schematic view showing one embodiment of an exposure system for forming the CHMSL hologram of FIG. 4;

FIG. 12 is a side view of a mask and a baffle used in the exposure system of FIG.

FIG. 13 is a plan view of a mask and a baffle used in the exposure system of FIG.

FIG. 14 is a schematic diagram of a mask used to define a hologram cell in the exposure setting of FIG. 11 to construct the hologram of FIG. 4;

FIG. 15 is a schematic diagram showing one embodiment of a copying system for forming a hologram copy of a hologram master formed according to the exposure systems of FIGS. 7 and 11;

Continued on the front page (72) Inventor Ronald T. Smith United States, CA 90504, Torrance, Number 215, Yukon Avenue 16700 (72) Inventor Michael Jay Bagadamo United States, California 91106, Pasadena, South Oakland Avenue 1079 (72) Inventor Richard Bee Upper, United States 91403, California, Sherman Oaks, Halvent Avenue 4713 (56) References JP-A-6-32174 (JP, A) JP-A-6 JP-A-281819 (JP, A) JP-A-6-316239 (JP, A) JP-A-7-232591 (JP, A) JP-A-7-232593 (JP, A) JP-B-6-98907 (JP, B2) US Pat. No. 5,455,692 (US, A) US Pat. No. 5,495,227 (US, A) US Pat.

Claims (5)

(57) [Claims] 1. A light source for providing a reconstructed beam, comprising: a non-overlapping array of hologram cells and non-hologram cells, each hologram cell being a first predetermined according to a diffraction of a portion of the reconstructed beam. First to generate a diffuse image that is observable in an angled field, and to generate a pattern of light and dark areas.
A first array of hologram cells and non-hologram cells arranged in a predetermined pattern, and an array of non-overlapping hologram cells and non-hologram cells, each hologram cell diffracting a portion of the reconstructed beam. Generate a diffuse image that is observable in a second predetermined angle field according to
A hologram cell and a second array of non-hologram cells arranged in a predetermined pattern, whereby the diffuse image generated by the first and second holograms provides brake light illumination. A holographic mid-high mounted stoplight system for an automobile, characterized in that it is formed. 2. The method according to claim 1, wherein said first array of hologram and non-hologram cells is formed in a first hologram layer, and said second array of hologram and non-hologram cells is formed in a second hologram layer; First and second
The holographic mid-high stoplight system for an automobile according to claim 1, wherein the hologram layers are combined so as to be stacked on each other. 3. A light source for providing a reconstructed beam, comprising an array of non-overlapping hologram cells and non-hologram cells, each hologram cell having a predetermined angular field according to the diffraction of a portion of the reconstructed beam. Comprising an array of hologram cells and non-hologram cells arranged in a predetermined pattern to produce a diffuse image observable at and producing a pattern of light and dark regions, whereby the hologram cell comprises The holographic mid-high mounted stoplight system for a motor vehicle, wherein the generated diffuse image forms a stoplight illumination. 4. A light source for providing a reconstructed beam, comprising an array of non-overlapping bright and dim hologram cells, each hologram cell having a first predetermined hologram cell according to a diffraction of a portion of the reconstructed beam. A first array of hologram cells arranged in a first predetermined pattern to produce a diffuse image observable in a given angular field and to produce a pattern of bright and dim areas; A hologram cell and an array of dim hologram cells, each hologram cell producing a diffuse image observable in a second predetermined angular field according to the diffraction of a portion of the reconstructed beam, and A second predetermined to generate the pattern A second array of hologram cells arranged in turns, whereby said diffused image produced by said first and second holograms forms a stoplight illumination. Holographic central high mounted brake light system. 5. A light source for providing a reconstructed beam, comprising an array of non-overlapping bright and dim hologram cells, each hologram cell having a predetermined angle according to the diffraction of a portion of the reconstructed beam. Comprising an array of hologram cells arranged in a predetermined pattern to produce a diffuse image observable in the field and to produce a pattern of bright and dim areas, whereby the hologram cell produced by said hologram cell The holographic mid-high mounted stoplight system for an automobile, wherein the diffuse image forms a stoplight illumination.