JP4681077B1 - Lighting device - Google Patents

Abstract

An illumination device with excellent color rendering is realized by mixing light sources provided in four directions with high efficiency and controlling a radiation angle.
[Solution] The angle γ formed by the inclined surface of the triangular wave refraction grating with respect to the emission direction is set by the difference between the incident angle α and the refraction angle β, and the ridge is arranged upward.
A lighting device comprising a two-plate structure in which the ridge direction is orthogonal to the lower side and the ridge of another triangular wave-like refractive grating is arranged upward.
Light from the four-direction light source enters the lower refractive grating, propagates light in two directions parallel to one inclined surface of the lower refractive grating, and another two directions parallel to the other inclined surface forming the pair. Propagate light. These are refracted by the pair of inclined surfaces and emitted in two directions perpendicular to the reference surface when viewed from the ridge axis direction.
Light that is mixed and concentrated in four directions from four directions enters the reference surface of the upper refractive grating, and one light propagates parallel to one inclined surface and enters the other inclined surface at an incident angle α and is refracted. Refracts at an angle β. The other light also propagates in the same manner, so that all four colors are emitted in the same direction.
[Selection] Figure 2

Description

  The present invention relates to an illuminating device that mixes light in four directions by controlling the emission direction with a triangular prism-shaped refractive grating.

A backlight of a liquid crystal display device using a light emitting diode uses a fluorescent white light emitting diode that mixes three primary colors of red, green, and blue, or irradiates a phosphor with blue light of a blue light emitting diode and uses complementary colors. .
In a structure in which the light emitting elements of three colors are housed near the focal point of one concave mirror, the colors are not mixed uniformly. Therefore, the difference in the distance and angle between each light emitting element and the reflecting mirror is made by making the inclination of the reflecting mirror near the light emitting element steep. There is a proposal to relax (FIG. 19, Patent Document 1) and the like.

The fluorescent white light emitting diode is a light emitting diode that is recognized as white by a complementary color by irradiating the yellow phosphor with the blue light of the blue light emitting diode. Since it can be manufactured more easily than the mixed colors of the three primary colors, it is used as a backlight for liquid crystal display devices such as mobile phones and LED bulbs. A large luminous flux is obtained with a light-emitting diode because a large number of chips are required and the spectrum is strong and bluish with emphasis on efficiency. The spectrum of a fluorescent white light-emitting diode has a sharp blue color and 2 in a gentle yellow range. It consists of two peaks (Patent Document 2). Even if the fluorescent white light by the complementary color itself is recognized as white, the irradiated object in the red region or the dip wavelength region becomes darker than the white light in the continuous spectrum. There are proposals for mixing red phosphors and the like, and replacing yttrium with gadolinium and shifting to the longer wavelength side to improve efficiency while improving color rendering (Patent Document 2).

When the white light of the backlight is separated into three colors by the color filter, 2/3 of the light amount is absorbed by the color filter and the efficiency is lowered. For this reason, efficiency improvement is anticipated by using a three primary color light emitting element, without using a color filter. There has been proposed a liquid crystal display device in which light sources of three colors are installed on three sides of a liquid crystal panel, square pyramids are provided in a matrix on a light guide plate, and predetermined pixels of the liquid crystal panel are irradiated by inclined surfaces of the quadrangular pyramids (see FIG. 20, Patent Document 3).

When two colors of light are incident on the bottom surface of the prism having an apex angle of 90 ° from the two directions, the incident light from the prism surface having a small incident angle is emitted by mixing the refracted light in the same direction and the prism surface having a large incident angle. Since the incident light is totally reflected at a critical angle or more, it returns to the other light source. In the prism having an apex angle of 90 °, a returning light beam is generated, and in order to utilize this, a structure for emitting light from another light source side using a bandpass mirror has been proposed (FIG. 21, Patent Document 4).

A white light source is proposed in which light emitting elements of 6 to 9 colors are arranged near the center of the substrate, enclosed in a lens shallower than the focal plane, and mixed with a scattering layer on the focal plane. Are connected at half-value wavelengths of each color having a wavelength width of 20 nm to 60 nm at which the peak is about half the peak value, so that continuous spectrum diffused light is realized (Patent Document 5).

The long axis direction of the strip-shaped reflecting surface is arranged on the horizontal plane so as to be orthogonal to the traveling direction of the parallel light from the light source, and the short axis direction of the strip-shaped reflecting surface is alternately inclined by ± 30 ° to form a triangular wave shape. Are arranged, the triangular wave reflection grating 4 is formed. There has been proposed a structure in which a parallel light source is provided at a symmetrical position in a direction obliquely upward 30 ° in the minor axis direction of the triangular wave reflection grating and the strip-like reflection surface. Since the reflecting surfaces forming the pair of each parallel light source and the triangular wave lattice are parallel, they cannot enter the reflecting surface arranged on the side of the parallel light source forming the pair, and the parallel light source 30 ° above the horizontal plane. Parallel light from both sides is incident along the light source direction reflecting surface of the triangular wave reflector. When the light enters the reflecting surface along the parallel light of the facing light source, the light incident from both is reflected vertically upward (FIG. 22, Patent Document 6).

When the refractive index n2 of the refractive grating constituent material and the refractive index n1 of the surrounding medium are set and light incident on the inclined surface from the refractive grating constituent material at an angle α is refracted at an angle β, the inclined surface angle of the V-shaped groove is the center line Since γ is incident in parallel on the opposite refracting surface, the right light source light is incident only on the right inclined surface, and the inclined surface and the incident light are symmetrical, so the left light source light is the same. By setting the inclined surface angle γ of the V-shaped groove by the difference between β and α, both refracted lights are emitted parallel to the center line. When entering the horizontal surface of the refraction grating symmetrically from the left and right at an angle δ, the light enters the refraction surface at an angle α and is mixed and emitted as parallel light (FIG. 1, Patent Document 6).
Refractive gratings can be stacked in the direction of travel, so a four-way mixing device (FIG. 23) and an eight-way mixing device (FIGS. 24 and 25) are shown in combination with the reflection type. White light is shown (Patent Document 6).

JP 2004-87935 A Japanese Patent No. 3246386 JP 2006-323221 A JP 2008-218154 A Japanese Patent No. 4114173 Japanese Patent No. 4399678

The proposal of Patent Document 1 in which three color light emitting elements are arranged in the same package and the colors are mixed by a structure such as steep inclination of the reflecting mirror in the vicinity of the light emitting element is different in distance and angle from each light emitting element to the reflecting mirror. This produces color spots that follow the tip.

  A white light emitting diode with a complementary color obtained by irradiating a yellow phosphor with blue light from a blue light emitting diode has a sharp blue light and a gentle yellow light spectrum, and lacks a red region and a blue green region (Patent Document 2). ). As the blending ratio of the phosphor increases, the peak of blue light decreases and the peak of fluorescence increases.However, when the fluorescence passes through the phosphor in the direction of travel, it exhibits yellow light and hits another yellow phosphor. The fluorescent material is absorbed because it is colored and opaque and has a low fluorescence conversion rate with respect to the fluorescence wavelength. Increasing the phosphor blending ratio by compensating for absorption further reduces the efficiency. Fluorescent white light emitting diodes are blue light with a high blue light spectrum, giving priority to efficiency, and have a low color rendering property with an average color rendering index of about 70.

In order to improve the color rendering by mixing phosphors in a wide wavelength band, it is necessary to mix phosphors in a mixing ratio according to conversion efficiency and specific luminous efficiency. There is a need to increase the amount of phosphor. The light emitted from the long-wavelength phosphor is absorbed only by the short-wavelength phosphor and is not converted to fluorescence, so it is necessary to increase the number of phosphors. There is a problem in that the efficiency decreases because the probability that yellow fluorescence hits the yellow phosphor and the probability that red fluorescence hits the red phosphor also increases.

  The proposal of Patent Document 3 in which a large number of quadrangular pyramid reflectors are provided on the bottom surface of the light guide plate, and the three primary colors from three directions are reflected on the pixels and mixed, is only reflected by the inverted V-shaped reflected light by the front quadrangular pyramid. If it is not obtained and oblique parallel light is irradiated to the quadrangular pyramid, it also hits the side surface, so that it becomes scattered light and enters other pixels and becomes unclear.

  The proposal of Patent Document 4 that refracts on one inclined refracting surface of a right-angle prism and emits in the vertical direction is totally reflected and incident on the other light source side because the incident angle on the other refracting surface is greater than the critical angle (see FIG. 21). In order to avoid the loss of the totally reflected light incident on the other light source side, it is complicated and expensive because it is re-reflected by a band pass mirror.

Patent Document 5 discloses a white light source in which seven types of light-emitting elements are arranged near the center of the substrate, sealed in a lens shallower than the focal plane, and mixed at a half-value wavelength of each color by mixing in a scattering material layer on the focal plane. Since the proposal mixes colors in the scattering layer on the focal plane, the emitted light is diffuse light. In order to use for illumination with a narrow radiation angle such as a spotlight, an optical system having a large diameter that can consider the scattering material layer as a focal point is required.

The refractive grating disclosed in Patent Document 6 has a structure in which parallel light from two directions is mixed and emitted as parallel light. When mixing light in four or more directions, a total of three refractive gratings that mix two colors and one refractive grating that mixes four colors form a triangle, so a thick structure is required.

The angle formed by the inclined surface of the refraction grating formed in a triangular wave shape with the vertical direction is γ, and when light incident on the inclined surface from the refraction grating constituent material with an incident angle α is refracted at the refraction angle β, the angle γ is the refraction angle. If set by the difference between β and the incident angle α, the refracted light emitted from the two inclined surfaces will be emitted parallel to the vertical line (Fig. 1).


Table 1 shows examples of α, β, γ, and δ of polymethyl methacrylate, cycloolefin resin, polycarbonate, and polyethylene terephthalate, which are representative transparent polymers obtained from Equations 1 and 2.

Assuming that the horizontal plane of the refractive grating in FIG. 1 is a reference plane, it enters the reference plane from the left and right at an incident angle δ. FIG. 2 shows a structure in which two refracting gratings are used and the ridge directions are orthogonal to each other. This is called a two-piece orthogonal refractive grating, and of the two refractive gratings, the upper side is called the upper side refractive grating and the lower side is called the lower side refractive grating. FIG. 2 includes four rays a, b, c, and d from light sources in four directions, but in the cross section of the upper refractive grating, one incident light consists of two rays a and c, and the other. Incident light consists of two rays c and d.
Light rays a and c that are incident on the reference surface of the upper refractive grating at an incident angle δ travel in parallel to the inclined surface A of the upper refractive grating and exit in the vertical direction at the inclined surface B, and are incident on the reference surface of the upper refractive grating at the incident angle δ. The light rays b and d incident in (5) travel parallel to the inclined surface B of the upper refractive grating and exit in the vertical direction on the inclined surface A.

The light traces on the lower refractive gratings of the rays a and c and the rays b and d that are incident on the reference surface of the upper refractive grating symmetrically at an incident angle δ will be described.
The light rays a and b propagate in the lower refractive grating parallel to the inclined surface D and exit from the inclined surface C, but the light rays a and b are emitted from the inclined surface C in the ridge axis direction of the lower refractive grating ( It is perpendicular to the reference plane when viewed from the y-axis direction). When viewed from the orthogonal direction of the ridge (x-axis direction), it is bilaterally symmetric at an incident angle δ with respect to the reference surface of the upper refractive grating.
The rays c and d propagate in the lower refractive grating parallel to the inclined surface C and exit from the inclined surface D. The direction in which the rays c and d exit from the inclined surface D is y in the ridge direction of the lower refractive grating. It is perpendicular to the reference plane when viewed from the axial direction. When viewed from the orthogonal direction of the ridge (x-axis direction), the reference surface of the upper refractive grating is symmetrical with respect to the incident angle δ.
That is, the light rays a and b emitted from one inclined surface C of the lower refractive grating in two directions and the light beams c and d emitted from the other inclined surface D in two directions are refracted upward symmetrically from the left and right of the x axis. Incident on the reference plane of the grating. When viewed from the x-axis direction, light rays a and c enter the upper refractive grating, travel parallel to the inclined surface A, exit in the vertical direction at the inclined surface B, and enter the reference surface of the upper refractive grating at an incident angle δ. The light rays b and d proceed parallel to the inclined surface B of the upper refractive grating and exit in the vertical direction on the inclined surface A.

A direction in which the four light beams enter the reference surface of the lower refractive grating for emitting the light vertically in the upper refractive grating will be described.
In order for the light beam a to be emitted in the vertical direction by the upper refractive grating, the emitted light from the lower refractive grating is inclined light having an angle δ with respect to the vertical direction when viewed from the x-axis direction. For this reason, the incident light to the reference surface of the lower refractive grating is also inclined light having an angle δ that is perpendicular to the x-axis direction. When viewed from the y-axis direction, the incident angle is an angle δ formed with the z-axis as in FIG.
In order for the light beam b to be emitted in the vertical direction by the upper refractive grating, the emitted light from the lower refractive grating is inclined light having an angle δ that is perpendicular to the x-axis direction, but the arrow direction of the y-axis in FIG. If it is positive, it is negative δ.
The angle formed with the z-axis is δ for all four rays. When viewed in plan from the emission direction of the upper refractive grating, incident light is incident from four directions at an angle δ from the ridge axis direction of the lower refractive grating as shown in FIG. The light beams a, b, c, and d of the four colors from the light sources a, b, c, and d are emitted in parallel to the vertical direction of the reference plane, but have dimensions that cannot visually recognize the optical path difference of the four parallel lights. By doing so, it is possible to mix colors uniformly. For indoor and outdoor use, the distance from the eyes to the refractive grating is different, so the dimensions that cannot be visually recognized are significantly different. However, since the liquid crystal display of a notebook computer viewed from several tens of centimeters is about 100 μm, About 0.01 °. The standard of the refractive grating pitch when the distance L from the eye to the refractive grating is long is expressed by Equation 3.

4 and 5 show examples of a structure in which the two-piece orthogonal refractive grating and the light source are viewed in plan from the emission direction. In the circular orthogonal refraction grating, the top edge of the upper refraction grating is indicated by a solid line, and the top edge of the lower refraction grating is indicated by a broken line. Since the light source direction is the incident angle δ, as shown in Table 1, it is 41.9 ° for polymethylmethacrylate (PMMA) and 48.1 ° for the angle with the reference plane. When a circular orthogonal refractive grating is irradiated from a direction where δ is 41.9 °, the aperture shape of the light source is an ellipsoid whose minor axis dimension is about 3/4 of the major axis dimension. FIG. 4 shows an ellipsoidal aperture shape provided with seven microlenses focused on seven light emitting elements on a substrate.

FIG. 5 shows an elliptical refraction grating having a minor axis dimension of about 3/4 of the major axis dimension and a structure in which the parallel light from two-way rotary parabolic mirrors is irradiated and mixed in four directions. When light from four directions is irradiated onto the orthogonal refractive grating, a total of eight colors can be mixed and emitted as parallel light.

FIG. 6 shows a structure in which two refractive gratings are integrated into one sheet. The cost can be reduced and the direction and position can be easily adjusted during assembly by using a single structure. The upward refracting grating is the same as the inclined surfaces A and B shown in FIGS. 1 and 2, but the downward refracting grating is composed of inclined surfaces E and F that form downwardly convex ridges. In order to distinguish from a two-piece refractive grating, it is called a double-sided orthogonal refractive grating, and the double-sided refractive grating is called an upward refractive grating and a downward refractive grating.
Unlike the two-piece orthogonal refraction grating, since there is no horizontal reference plane, the four light beams go straight between the refraction gratings on both sides at an angle γ formed with the vertical line.
As shown in the sectional view 7 of the upward refractive grating, the light a emitted from the upward inclined surface B enters the inclined surface B at an incident angle α. In FIG. 7, the inclined surface F of the downward refractive grating is not a cross section but is viewed from the side, and the incident point on the inclined surface F is indicated by ◯.

As shown in the sectional view of the downward refracting grating, it is necessary to totally reflect the inclined surface E in the vertical direction when viewed from the axial direction (y-axis direction) of the ridge of the downward refracting grating. Assuming that the angle formed by the inclined surface E and the vertical line when viewed from the x-axis direction orthogonal to the ridge is ε, the light a and b totally reflected by the inclined surface E are incident light refracted by the inclined surface F of the downward refractive grating. is there. Similarly, light c and d totally reflected by the inclined surface F is incident light refracted by the inclined surface E of the downward refractive grating. An incident angle λ and a refraction angle κ as seen from the y-axis direction on the inclined surfaces E and F are expressed by Equation 4.

The angle between the inclined surface viewed from the x-axis direction and the refracted light is χ, and the inclined surfaces E and F for entering the inclined surface F as seen from the ridge axis direction of the downward refractive grating are vertical lines. The inclination angle ε formed is 30 ° from χ = 90 ° in Equation 5 and 60 ° at the apex angle 2ε.

FIG. 9 shows the trace of incident light viewed from the y-axis direction when the inclined surface of the downward refractive grating is 30 °, 27 °, and 33 °. If the inclination angle ε is less than 30 °, the light beam that has passed near the top edge is irradiated above the upper end of the total reflection surface and cannot be emitted in the vertical direction by the upward refracting grating, and the color mixing characteristics deteriorate. Since the incident light ε27 reaching the upper end of the total reflection surface at 27 ° passes away from the top edge, 25% of the light passing closer to the top edge cannot be reflected in the vertical direction by the total reflection surface. The color mixing characteristics deteriorate. When the inclination angle ε exceeds 30 °, the angle formed by the incident light with respect to the horizontal plane is less than 30 °, and the light beam that has passed near the apex cannot effectively use the entire total reflection surface. When it is 33 °, it is blocked by the adjacent top edge, so that there is no incident light reaching the upper end of the total reflection surface, and the light ray ε33 that has passed near the top edge is irradiated below the upper end of the total reflection surface. For this reason, a blank area of emitted light is generated between the upper end of the total reflection surface. When the inclination angle ε is 33 °, a blank region of about 30% is generated in a striped pattern.

The light is totally reflected by the inclined surface of the downward refractive grating to form a tilted light having an angle γ that forms a vertical line. When the inclination angle ε is 30 °, the inclined surface viewed from the x-axis direction does not travel straight, but is refracted at the incident point as shown in FIGS. In the case of polymethyl methacrylate, γ is 26.6 °, so the incident angle is 41.9 °.
Since the direction of the light source incident on the downward refractive grating of the double-sided orthogonal refractive grating is about 30 ° downward from the horizontal plane, the light source size can be reduced. For this reason, the opening shape of the light source is an ellipsoid whose minor axis dimension is about half of the major axis dimension. FIG. 13 shows an embodiment in which seven microlenses having seven light emitting elements as focal points are provided on an ellipsoidal substrate. A plurality of rotary parabolic mirrors may be formed on an ellipsoidal substrate having a minor axis dimension that is approximately half the major axis dimension.

If the density of the downward refracting grating in the double-sided orthogonal refracting grating is halved and every other flat portion is provided, four different colors of light can be transmitted through the flat portion. Since the traveling directions of the other four-color lights that pass through the flat portion are the same as the traveling directions via the E and F planes, they are refracted on the A and B planes and emitted in the vertical direction. FIG. 10 shows a structure in which every other flat portion is provided in the downward refractive grating in the double-sided orthogonal refraction grating, and only the lower refractive grating having every other flat portion is provided therebelow. The downward refractive grating having a flat portion provided below does not have an upward refractive grating. With this two-layer structure, eight colors can be mixed.

If the light beam that has passed near the top edge of the downward refractive grating is irradiated on the upper side of the total reflection surface, it cannot be emitted vertically by the upward refractive grating. In order to avoid this, a state in which the total reflection surface below the boundary with the flat portion is irradiated is shown in FIG. 10, and the entire surface of the total reflection surface can be used under this boundary condition. The inclination ε of the downward refractive grating at this time is 34.6 ° for polymethyl methacrylate having a refractive index of 1.49, and 34 ° for polyethylene terephthalate having a refractive index of 1.66. Table 2 shows the angle ε, the incident angle λ, the refraction angle κ, and the angle ω between the incident light and the horizontal plane.

In Table 2, ε represents the optimum value of a typical transparent polymer. Since the refractive index of the transparent polymer is about 1.4 to 1.7, if ε is smaller than the optimum condition, the color mixing characteristics deteriorate, and if it is larger, a blank area is generated. The inclination ε of the downward refractive grating is preferably set in the range of 31 to 38 °. The apex angle is 2ε. Incident when the light passing through the vicinity of the top edge of the downward refractive grating irradiates the total reflection surface below the boundary with the flat part using a two-layered orthogonal refractive grating with a flat part in the downward refractive grating The angle ω between the light and the horizontal plane is about 14 °, which is half of that in FIG. 8, so that the light source can be made thinner. A cross-sectional view including a light source portion using a two-layered orthogonal refraction grating is shown in FIG.

In an illuminating device having a wider emission angle than parallel light, a concave lens array is provided for expanding the emission angle of mixed color parallel light by using a negative focal length optical system, or the inclined surface of the refractive grating is made concave. Can expand the radiation angle. 11 and 12, a concave lens array is provided for expanding the radiation angle as compared with parallel light. If the mixed parallel light emission direction is different, only one of the components will be produced, resulting in color spots, so that the concave lens pitch is narrower than the refractive grating pitch and the mixed parallel light emission angle and direction are aligned to produce uniform color mixing light. Can be irradiated. Uniform color mixing light can also be irradiated by making the refractive grating inclined surface concave and aligning the emission angle of the emitted light.

When a large amount of a plurality of phosphors are mixed in the fluorescent white light emitting diode, the fluorescence is absorbed by other phosphors and the efficiency is further lowered. However, when the colors are mixed by the refractive grating, the wavelength characteristic is broadened without reducing the efficiency. Since it is not a color mixture due to scattering, it is possible to irradiate white light with a narrow emission angle.
FIG. 16 shows spectral characteristics obtained by mixing colors in the structure shown in FIG. 4 using four types of individual light emitting diodes.
FIG. 18 shows spectral characteristics in which two types of fluorescent white light emitting diodes having different excitation wavelengths and fluorescence wavelengths are used in combination in a four-direction light source using the structure shown in FIG. Since it is complemented by the phosphor band, the unevenness can be reduced as compared with the spectrum of four types of individual light emitting diodes.
Since the wavelength width at which the luminous intensity of the light emitting diode is about half of the peak is 20 nm to 60 nm, it is possible to realize continuous spectrum white light by using eight types of individual light emitting elements connected at half wavelength of each color. 8 colors can be mixed in the structure shown in FIGS. 5 and 10 to synthesize white light having a continuous spectrum as shown in FIG.

Two refracting gratings are orthogonally arranged, and light beams from four directions are emitted in two directions from two inclined surfaces of the lower refractive grating and are incident on the inclined surface of the upper refractive grating at an incident angle α. Since the four colors can be mixed by arranging the light sources, it is possible to construct the refraction grating more easily and thinner than a structure in which a conventional refractive grating is assembled into a triangle.
Since a double-sided orthogonal refraction grating can mix light in four directions, it can be configured more easily and thinner than a structure in which a conventional refraction grating is assembled into a triangle.
Since the light of eight directions can be mixed by the structure of the downward refracting grating etc. which provided the flat part, the continuous spectrum white light with a good color rendering property can be radiate | emitted.
Since they are mixed and emitted as parallel light in the same direction, they can be emitted at any radiation angle in combination with other optical systems.
Since there is no absorption that broadens the wavelength characteristics by mixing phosphors, color mixing can be performed with high efficiency.

Principle of color mixing with triangular wave refraction grating A perspective view of a structure in which triangular wave refraction gratings are orthogonally arranged to mix light in four directions Plan view of a structure in which triangular wave refraction gratings are orthogonally arranged to mix light in four directions Plan view of structure irradiating circular orthogonal triangular wave refraction grating from elliptical light source in 4 directions Plan view of a structure that irradiates a circular orthogonal triangular refracting grating using four sets of elements that irradiate and mix parallel light from two directions on a rotating parabolic mirror to an elliptic triangular refracting grating. A perspective view in which an upward refractive grating and a downward refractive grating are provided perpendicular to both surfaces and light in four directions is mixed. Cross section of upward refraction grating in double-sided orthogonal refraction grating Cross section of downward refractive grating in double-sided orthogonal refractive grating Conceptual diagram of tilt angle and light trace of downward refractive grating in double-sided orthogonal refractive grating A downward refracting grating provided with a flat part mixes light in four directions, and an upward refracting grating and a downward refracting grating provided with a flat part are orthogonally provided on both sides, and light in four directions is mixed to obtain a flat part. Sectional view of a structure that mixes light in 8 directions in total by irradiating the mixed light in 4 directions FIG. 10 is a cross-sectional view of a structure in which light in eight directions is mixed with a light source section using a parabolic mirror, a concave lens for expanding a light beam of mixed parallel light, and a two-layered refractive grating in FIG. Cross-sectional view of a double-sided orthogonal refraction grating, a light source unit in which light-emitting elements are arranged on a substrate to form parallel light with a lens, and a headlight that expands the mixed parallel light in a horizontal direction with a concave lens Irradiation area of light source unit in front view of headlight of FIG. Irradiation range by the headlight having the structure shown in FIGS. LED bulb using a mixed structure in eight directions with a downward refractive grating provided with a flat part Spectrum of a four-color mixed white light source Spectrum of 8-color mixed white light source Spectrum of white light source by mixing in four directions using two fluorescent white light emitting diodes Conventional LED package that mixes colors by relieving color spots by making the reflector near the chip steeply inclined Conventional example of irradiating a predetermined pixel with three-color light by an inclined surface of a quadrangular pyramid provided on a light guide plate Conventional example in which light in two directions is incident on a right-angle prism and mixed with a band-pass mirror Mixing of parallel light from two directions by triangular wave reflection grating Side view of a conventional four-color mixing device using a reflective / refractive grating Side view of a conventional 8-color mixing device using a reflective / refractive grating Perspective view of a conventional 8-color mixing device using a reflective / refractive grating

Example 1
An example of a structure in which two refractive gratings are orthogonal to each other and a structure in which the light source is viewed in plan view from the emission direction will be described with reference to FIG. The circular orthogonal refractive grating has the configuration shown in FIG. The angle formed by the inclination of the refractive grating with respect to the vertical direction is 26.6 ° for polymethylmethacrylate, so the apex angle is 53.2 °. The top ridge of the upper refractive grating is indicated by a solid line, and the top ridge of the lower refractive grating is indicated by a broken line. When a circular orthogonal refractive grating is irradiated from a direction where δ is 41.9 °, the aperture shape of the light source is an ellipsoid whose minor axis dimension is about 3/4 of the major axis dimension. When seven light emitting elements are provided on an ellipsoidal substrate and are composed of seven spherical microlenses having these as focal points, parallel light of an elliptical light beam can be formed. In FIG. 7, the shape of the microlens is shown as a hexagon having an aspect ratio of 3/4, but the lens surface is spherical.
FIG. 4 shows a structure in which four light source portions are provided obliquely below the circular orthogonal refractive grating in order to irradiate the circular orthogonal refractive grating from the direction where δ is 41.9 °. FIG. 16 shows spectral characteristics when four-color light emitting diodes are used.

Example 2
An example in which four sets of configurations for mixing parallel lights from two-direction rotating paraboloid mirrors and two refracting gratings are applied to orthogonal refracting gratings to mix eight colors will be described with reference to FIG. . The two orthogonal refractive gratings are the same as in the first embodiment. In addition to the orthogonal refractive grating at the center of FIG. 5, an elliptical refractive grating having a minor axis dimension of about 3/4 of the major axis is provided in four directions. The elliptical refraction grating has the function of mixing the parallel light from the rotating paraboloid mirrors in two directions, and irradiates the circular orthogonal refraction grating from the direction where δ is 41.9 °. An ellipsoidal refractive grating having an axial dimension of about 3/4 is used.

Example 3
An embodiment will be described in which light from a double-sided orthogonal refraction grating and a light source provided in four directions is mixed. The circular orthogonal refractive grating has the structure shown in FIGS. The angle formed by the inclination of the upward refractive grating with respect to the vertical direction is 26.6 ° in polymethylmethacrylate, so the apex angle is 53.2 °. The top ridge of the upper refractive grating is indicated by a solid line, and the top ridge of the lower refractive grating is indicated by a broken line. When irradiating from a direction 30 ° below the horizontal plane of the circular double-sided orthogonal refractive grating, the opening shape of the light source is an ellipsoid whose minor axis dimension is half of the major axis dimension. The light source shown in FIG. 4 is provided with four light source portions obliquely below the circular orthogonal refractive grating in order to irradiate the circular orthogonal refractive grating in a direction 30 ° below and 41.9 ° from the y-axis. The structure of the light source part is slightly longer than the part. When seven light emitting elements are provided on an ellipsoidal substrate and are composed of seven spherical microlenses having these as focal points, parallel light of an elliptical light beam can be formed.

Example 4
An illumination unit that provides flat portions every other downward refracting grating and mixes eight colors that transmit other four colors of light to the flat portions will be described with reference to FIG. In order to align the radiation angle and direction, the aperture diameter of the microlens is set to twice the pitch of the refractive grating. The mixed parallel light can be used as a downlight unit by providing a micro concave lens array with a radiation angle of 30 ° to widen the radiation angle. If it is set to 60 °, it can be applied to a ceiling lamp composed of a plurality of units.
The mixed spectrum is white light having a continuous spectrum as shown in FIG.

Example 5
An example of a headlight that mixes light from a double-sided orthogonal refractive grating and light sources provided in four directions will be described with reference to FIGS. When the circular double-sided orthogonal refraction grating is irradiated from a direction of 30 °, the opening shape of the light source is an ellipsoid whose minor axis dimension is half of the major axis dimension. When seven light emitting elements are provided on an ellipsoidal substrate and are composed of seven spherical microlenses having these as focal points, and the shape of the microlens is pentagonal or hexagonal, the cross section of the luminous flux is pentagonal or hexagonal. Parallel light can be formed. FIG. 12 shows a cross-sectional view of a headlight structure in which the mixed parallel light is expanded in the horizontal direction by a concave lens, and a radiator is provided on the back surface of the substrate on which the light emitting element is mounted. FIG. 13 is a front view of the headlight. A double-sided orthogonal refraction grating is shown in the center of FIG. 13, the top edge of the upper refraction grating is indicated by a solid line, and the top edge of the lower refraction grating is indicated by a broken line. The seven hexagons shown on the double-sided birefringent grating indicate that the parallel light from the seven microlenses of the light source provided in four directions is synthesized within the hexagonal range. The same effect can be obtained by using a concave mirror instead of a microlens.
A cylindrical or oval concave lens array is provided in front of the double-sided orthogonal refractive grating to expand the light beam, but expands the light beam more widely in the horizontal direction than in the vertical direction.
The opening shape of the light source provided in the four directions is an ellipsoid whose minor axis dimension is half of the major axis dimension, and is composed of seven hexagons. FIG. 14 shows the irradiation range by the headlight. When the two upper hexagons are turned off, the inclined portion of the hexagon passes the cut-off line of the beam irradiation range. When the fluorescent white light emitting diode is used, the visibility can be improved by reducing the unevenness as compared with the mixed color of four colors as shown in FIG.

Example 6
An embodiment as an LED bulb will be described with reference to FIG. 15 and the like using a mixed structure in eight directions by a double-sided refractive grating with a flat part and a downward refractive grating with a flat part. If the radiation angle of the mixed parallel light is expanded by the micro concave lens array, it can be used for general illumination. In order to align the radiation angle and direction, the aperture diameter of the microlens is set to twice the pitch of the refractive grating. Local illumination is obtained at a radiation angle of about 30 ° by the micro concave lens array above the refractive grating, but a total reflection surface for illuminating the side surface and a side concave lens array are provided so that the radiation angle is close to the radiation angle of the incandescent bulb.
A structure in which another four-color light is transmitted and mixed into a double-sided refractive grating with a flat portion provided with a flat portion on the downward refractive grating irradiates parallel light from a light source approximately 14 ° below the horizontal plane. The light source unit is a light emitting diode with a lens provided on a substrate. The mixed spectrum is white light having a continuous spectrum as shown in FIG.

1: Light-emitting element 2: Inclined surface 3: Incident light 4: Triangular reflection grating 5: Convex reflection surface 6: Parabolic mirror
7: Reference surface 8: Convex lens 9: Orthogonal refraction grating 10: Convex refraction surface 11: Concave refraction surface 12: Incident point 13: Double-sided refraction grating with flat part 14: Downward refraction grating with flat part 15: Refraction grating 16: Both sides Orthogonal refraction grating 17: Flat part 18: Translucent material
19: Parallel light 20: Diffuse light 21: Concave mirror 22: Convex mirror 23: Cover 24: Cut-off line 25: Passing beam irradiation area 26: Traveling beam irradiation area 27: Center line 28: Road boundary line 29: Heat radiation material 30: Circuit board 32: Top ridge 38: Support member 43: Square pyramid 46: Light source 47: Band pass mirror 49: Right angle prism

Claims (6)

The angle γ formed by the inclined surface of the triangular wave refraction grating with respect to the emission direction is set by the difference between the incident angle α and the refraction angle β, and the ridge is arranged upward .
Below that, the ridge direction is orthogonal and the ridge of another triangular wave refraction grating is placed upward ,
A light beam from a light source in four directions is incident on the lower refractive grating, propagates light in two directions parallel to one inclined surface of the lower refractive grating, and emits light in another two directions parallel to the other inclined surface. By propagating, it emits in two directions perpendicular to the reference plane when viewed from the ridge axis direction ,
An illuminating device characterized by being emitted in the same direction by propagating in parallel to one inclined surface of the upper refractive grating, entering the other inclined surface at an incident angle α, and refracting at a refractive angle β . 2. The illumination device according to claim 1, wherein the angle γ formed by the inclined surface of the triangular wave refractive grating with respect to the emission direction is in the range of 26.6 ° to 29.2 °. The illumination apparatus according to claim 1, wherein eight colors are mixed and emitted as parallel light by providing a structure that irradiates and mixes parallel light in two directions in four directions. The angle γ formed by the inclined surface of the refractive grating with the exit direction is constituted by the difference between the refraction angle β and the incident angle α,
2. The illumination device according to claim 1, wherein the sum of the angle of refraction [beta] and the angle [gamma] formed by the inclined surface and the outgoing direction is 90 [deg.]. 2. The illumination device according to claim 1, wherein the opening shape of the light source is an ellipsoid whose minor axis dimension is about 3/4 of the major axis dimension. A pentagonal or hexagonal aperture light source is divided into a passing beam irradiation range and a traveling beam irradiation range, and a plurality of combinations are provided in four directions. The lighting device according to claim 1.