JP6694924B2 - Head-up display device and information display method - Google Patents

Description

  The present invention relates to, for example, a head-up display device that projects information such as an image on a windshield of an automobile or the like and directly projects the information on a human visual field through the windshield.

  It can be mounted on a vehicle such as an automobile, and the image is projected on a windshield (partial reflection means) with a metal thin film or a dielectric multilayer film formed on the inner surface, and the image is displayed as a virtual image in the view through the windshield. A head-up display device for displaying is already known from Patent Document 1 below.

  Further, in Patent Document 2 below, for example, a liquid crystal display mounted in a dashboard as a vehicular display device for pseudo-notifying the driver of wheels that the driver cannot directly see through the windshield It is disclosed that an image (image of a three-dimensional tire) projected from a display formed of a device is projected on a holographic combiner attached to a part (lower side) of the windshield.

  Furthermore, as a navigation device that guides the route, by projecting necessary guide information (for example, an arrow) on the windshield of an automobile, detailed map data etc. are not required, and the guide information can be easily and accurately provided. The one that displays to the driver is already known from Patent Document 3 below.

JP, 2006-258884, A JP-A-5-58196 JP, 2006-258884, A

  However, in the above-described conventional technology, it is possible to mount it in a narrow dashboard, and in particular, the brightness of the visible real image through the windshield (external light ) And the brightness of the information displayed by the projection means can be sufficiently secured (high contrast), and it is difficult to realize a head-up display device having excellent visibility.

  In addition, in general, when a projection device using a white lamp as a light source is applied, the light source becomes large in order to sufficiently secure the above-mentioned brightness and ratio, and thus it is necessary to install it in a narrow dashboard. It becomes impossible to install.

  Therefore, the present invention has been achieved in view of the problems in the above-described conventional technology, and in particular, it can be mounted in a narrow dashboard, and the brightness and its ratio (contrast) described above are sufficiently satisfied. It is an object of the present invention to provide a head-up display device that can be secured and has excellent visibility even in the presence of external light.

  In order to achieve the above-mentioned object, according to the present invention, a head-up display device for displaying information including an image in a part of the field of view of a pilot, the head-up display device being arranged at a position out of the field of view of the pilot. An image display device for generating and projecting image light for projecting the information; and a projection light from the image display device, which is arranged in a part of the visual field of the operator, transmits the light from the visual field, A solid screen that reflects and mixes light emitted from a plurality of light source cells as a light source constituting the image display device, and emits the light in a predetermined direction. A head-up display device using a light source device is provided.

  According to the present invention described above, it is possible to mount it in a narrow dashboard, and it is possible to sufficiently secure the above-mentioned brightness and its ratio (contrast), and the visibility is high even in the presence of external light. The excellent effect of enabling to provide a superior head-up display device.

It is a side view which shows the whole structure of the head-up display apparatus which becomes one embodiment of this invention. It is a side view which shows the internal structure of the image display apparatus which comprises the said head-up display apparatus. It is a top view which shows the internal structure of the image display apparatus which comprises the said head-up display apparatus. FIG. 3 is an enlarged perspective view and a cross-sectional view showing a specific structure of a light redirecting unit that constitutes the image display device. It is a perspective view which shows the concrete structure of the solid-state light source device which comprises the said video display apparatus. It is an expansion perspective view which shows the structure of the light reflection combining part of the said solid state light source device. It is an expansion perspective view which shows each part and the whole of the photosynthesis part of the said solid state light source device. It is a partially expanded sectional view which shows the relationship between the said photosynthesis part and a light source cell. It is a figure which shows an example of the reflection characteristic of the said optical-synthesis part wavelength-selective optical surface (film | membrane). It is a figure explaining composition of light in the inside of the above-mentioned light reflex composition part and an optical composition part. It is a side view explaining other Examples (Example 2) of the above-mentioned image display device. It is a figure explaining the three-dimensional (three-dimensional) display in the said other Example (Example 2). It is a side view explaining another example (Example 3) of the above-mentioned image display device. It is a side view explaining other Example (Example 4) of the above-mentioned image display device. It is a block diagram which shows an example of a structure of the said video display apparatus used as a light color circulation type modulation system. It is a signal waveform diagram which shows an example of operation | movement of the video display apparatus which becomes the said modulation system of a light color circulation type. It is explanatory drawing for demonstrating the effect by the image display apparatus used as the said light color circulation type modulation system. It is a lens block diagram which shows the concrete structure of the projection lens of the said image display apparatus. It is a ray figure explaining the characteristic of the said projection lens. It is a partially expanded perspective view and sectional drawing explaining other examples of the transparent screen which comprises the said head-up display apparatus. It is a top view for demonstrating the structure of the said transparent screen. It is a ray diagram which shows the characteristic of the said transparent screen. It is a side view which shows the whole structure of the head-up display apparatus which becomes other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, FIG. 1 attached herewith shows a head-up display device according to an embodiment of the present invention. , A schematic configuration of a vehicle head-up display device for displaying the information is shown. In the figure, a transparent screen 410, which is, for example, an antireflection film and constitutes a head-up display device, is attached along the inner surface of the lower side of the windshield indicated by reference numeral 400, while the head is The image display device 420 that constitutes the up-display device is mounted inside the dashboard 403 that is arranged at a position adjacent to the steering 404 on the lower side of the windshield 400.

  In the head-up display device having such a configuration, the image (information) from the image display device 420 is projected and reflected on the transparent screen 410 provided with the directional reflection means, and is supported by the driver seat 406 and the headrest 405. The image is projected on the eyes 409 of the driver (pilot) 407 who has been driven. As a result, the driver 407 can recognize various information necessary for driving that is simultaneously superimposed and displayed on a part of the external visual field that enters the eye 409 through the windshield 400, and is always external. It is possible to operate the steering 404 while determining the situation, and a safer driving operation becomes possible.

  Next, FIGS. 2 and 3 are diagrams showing an example of a more detailed configuration of the image display device 420 including the transparent screen 410, FIG. 2 is a side view thereof, and FIG. 3 is a top view. ..

  As shown in these figures, the image display device 420, whose details will be described below, has high light utilization efficiency, emits white light, or emits a desired color (for example, R (red), G (green) and B (blue) light can be selectively emitted, for example, a light source unit 421 using an LED light source or a laser light source, and light from the light source unit 421 from an external image. A light modulation unit (liquid crystal panel) 422, which is a device that converts a desired image light based on a signal, for example, a TFT liquid crystal panel, and the image light from the light modulation unit 422 is enlarged and projected. The so-called projection lens 423 and the light from the projection lens 423 is irradiated (projected) toward the transparent screen 410 mounted below the inner surface of the windshield 400, for example, a light direction made of a Fresnel lens sheet. The conversion unit 424 and the like are included. Further, reference numeral 430 in the drawing indicates a drive circuit for driving the light modulator 422 (for example, a liquid crystal panel, a reflective liquid crystal panel, a DLP element) based on an external video signal. In FIG. 2, among the wide-angle projection lights, the light projected on the upper end of the transparent screen 410 is the upper limit light, and the light projected on the lower end of the screen 410 is the lower limit light, respectively. , Reference numerals 412, 413.

  Incidentally, FIGS. 4 (A) and 4 (B) attached herewith show a specific configuration of the light direction conversion section 424. FIG. 4 (A) shows a Fresnel lens sheet as a light modulation section (liquid crystal panel). FIG. 4B is a cross-sectional view taken along the line GG, showing a perspective view seen from the 422 side. As is clear from these figures, a plurality of refraction-type Fresnel lenses 425 are concentrically formed in the light direction conversion section 424, and the light is converted and projected from the light modulation section (liquid crystal panel) 422. Light is emitted in a substantially vertical direction by the action of these Fresnel lenses 425 (see the arrow in the figure).

<< High-efficiency solid-state light source device >>
Next, with respect to the detailed configuration of the light source unit 421, which has high light utilization efficiency described above and can selectively emit light of a desired color including white, referring to FIGS. This will be described below.

  First, FIG. 5 shows the entire configuration of the light source unit 421, and as is clear from the figure, a light reflection combining unit 20, a light combining unit 30, and a plurality (in this example, for example, (4 sheets) of light source cells 40. In this figure, only two light source cells 40 are shown because of that viewpoint. Note that reference numeral 35 in the drawing indicates a light emitting surface of the light combining unit 30.

  As shown in FIG. 6, the light reflection synthesizing unit 20 is made of, for example, a member made of metal (aluminum or the like), having a high thermal conductivity and an inner surface having a polished surface for increasing the reflectance of light, and having a reflection-increasing coating. , A quadrangular cross-section, the tip portion of which is formed into a parabolic shape, the outer shape of which is a substantially pyramidal member, and the entire surface excluding the bottom portion, for example, A liters or A liters of metal. A reflective surface is formed by forming a multilayer reflection enhancing film.

  As shown in FIG. 7 (A), the light combining unit 30 assembles, for example, four dichroic prisms 31 each having a triangular cross section and a triangular columnar outer shape whose bottom surface is larger than the top surface. As shown in B), the cross section is a square prism. Each of the dichroic prisms 31 has a reflective surface on the surface 32 which is an outer peripheral surface in the assembled state, and the other two surfaces 33 and 34 are, for example, wavelength selection plates showing a dichroic characteristic composed of a metal multilayer film. A transparent optical surface (film) is formed.

  Here, returning to FIG. 5 again, the light source cells 40 are attached to the respective outer peripheral surfaces of the light combining section 30 (or the light reflection combining section 20). FIG. 8 shows a cross section of a portion of the light combining section 30 to which the light source cell 40 is attached. In this example, as is apparent from FIG. 8, four light source cells 40 are attached, and each light source cell 40 emits R (red) light which is the three primary colors of light. The light source cell 40R is a light source cell 40G that emits G (green) light, and the light source cell 40B that emits B (blue) light. In particular, the light source cell 40G that emits G light is Compared to the light source cell 40R that emits R (red) light and the light source cell 40B that emits B (blue) light, it is difficult to obtain a large output light, so that it is attached to two adjacent outer peripheral surfaces of the light combining unit 30. There is. In addition, the reflection surface formed on the surface of the portion to which the light source cell 40 is attached is removed.

  Next, in FIG. 8, the light combining section 30 formed by assembling the four dichroic prisms 31a to 31d and the light source cells 40a to 40d attached to the outer peripheral surface thereof are shown in cross section (however, The reflection surface formed on the surface is removed from the portion to which each light source cell 40 is attached.) Then, on the boundary surface of each photosynthetic portion 30, a wavelength-selective optical surface (film that exhibits the dichroic characteristics described above) is formed. ) 33a to 33d are arranged, whereby the light emitted from the light source cells 40a to 40d is reflected or passed by the wavelength-selective optical surfaces (films) 33a to 33d, and further mixed. This makes it possible to extract light of a desired color including white.

  Next, FIGS. 9A to 9C show an example of the reflection characteristics of the above-described wavelength-selective optical surfaces (films) 33a to 33d. That is, as also shown in these figures, the G light reflecting surface reflects light of wavelengths in the G region and transmits light of other wavelength regions. Similarly, the B-light reflecting surface reflects light having a wavelength in the B region, and the R-light reflecting surface reflects light having a wavelength in the R region.

  Here, the photosynthesis unit 30 of FIG. 8 will be described as an example. First, the light source cells 40a and 40b emit light of G (green) color, the light source cell 40c emits light of B (blue), and the light source cell 40d emits light of R (red). In addition, the wavelength-selective optical surface (film) 33a is G light reflective / R light transmissive, and the wavelength selective optical surface (film) 33b is R light, B light reflective / G light transmissive, and wavelength selective. The optical surface (film) 33c is G light reflective / B light transmissive, and the wavelength-selective optical surface (film) 33d is B light and R light reflective / G light transmissive. As a result, the R light, the G light, and the B light can be separated and extracted from the emission surface 35 (see FIG. 5).

  Alternatively, by appropriately selecting the reflection / transmission characteristics of the wavelength selective optical surface (film) described above, white light in which R light, G light, and B light are mixed is extracted from the emission surface 35 (see FIG. 5). You can also do it.

  Next, the combination of light inside the light reflection combining unit 20 and inside the entire light reflection combining unit 20 and the light combining unit 30 will be described with reference to FIGS. 10 (A) and 10 (B). It should be noted that these figures are cut surfaces obtained by cutting the light reflection combining unit 20 and the entire light reflection combining unit 20 and the light combining unit 30 along the optical axis direction (see the alternate long and short dash line in FIG. 5). .. The case where the light source cell 40 is attached to the upper surface of the light reflection / synthesis unit 20 will be described here.

  Considering the heat dissipation of the light source cell, the light reflection / synthesis unit 20 is preferably made of a metal such as A liter having a high thermal conductivity and an excellent light reflection characteristic, and the inner surface thereof is, for example, an ellipse, a paraboloid, or a spherical surface. The light fluxes emitted from 40a to 40d are efficiently guided to the photosynthesis unit 30. FIG. 10A shows a light reflection combining section 20 as an embodiment of the present invention, which has a substantially parabolic outer shape as a whole, and is an optical axis direction (FIG. The cross section along the alternate long and short dash line) is substantially parabolic. Further, the cross section perpendicular to the optical axis direction has a substantially elliptical shape from the central portion to the tip portion, and has a square or rectangular shape from the central portion to the joint portion with the light synthesizing unit 30. The section 20 and the photosynthesis section 30 have a shape in which they are continuously connected to each other. Further, as described above, a reflection surface is formed on the outer peripheral surface of the light reflection synthesizing unit 20, and the light emitted from the light source cell 40 is reflected by the light synthesizing unit 30.

  That is, in FIG. 10A, arrows indicate the propagation directions of the light emitted from the light emitting points 401 to 405 of the light source cell 40 in the light reflection combining unit 20. By making the tip end portion of the light reflection / synthesis unit 20 substantially parabolic, the light from each of the light emitting points 401 to 405 is mixed by repeating reflection inside the light reflection / synthesis unit 20, and as a result, the light synthesis is performed. The part 30 emits a light beam which is substantially uniformized.

  FIG. 10B is a diagram showing the propagation of light rays in the entire light reflection synthesizing unit 20 and the light synthesizing unit 30, and the light flux incident on the light synthesizing unit 30 from the light reflection synthesizing unit 20 is the outer periphery of the light synthesizing unit 30. While being reflected by the surface, the light density of the light flux is made uniform toward the emission surface and emitted to the outside. At this time, the light having a specific wavelength is reflected by the wavelength-selective optical surfaces (films) 33a to 33d by passing through the dichroic prisms 31a to 31d forming the light combining unit 30. That is, by providing the wavelength-selective optical surfaces (films) 33a to 33d, the number of reflections inside the light combining unit is greater than that in the case where the light is reflected only by the reflecting surface formed on the outer peripheral surface of the light combining unit 30. Is increased, and the light utilization efficiency is improved. As an example, when an aluminum reflection film is formed on the outer peripheral surface of the light combining unit 30 and internal light is reflected only by the reflection film, the reflection loss is about 5% / one reflection). However, by providing the wavelength-selective optical surfaces (films) 33a to 33d, on the other hand, the light that is transmitted without being reflected can also be used as the outgoing light flux after that. There is little decline.

  Further, by providing the wavelength selective optical surfaces (films) 33a to 33d, the number of reflections of light inside the light reflection / synthesis unit 20 increases, and the intensity distribution of the reflected light flux can be made more uniform. .. In other words, when the uniformity of the output light flux is constant, the length in the optical axis direction of the light reflection / synthesis unit 20 can be further shortened as compared with the reflection only on the outer peripheral surface. Furthermore, since the area of the entrance surface of the light combining section 30 (the exit surface of the light reflection combining section 20) is made larger than the area of the exit surface 35, the angle of the outgoing light beam approaches the direction of the optical axis, and The characteristics can be narrowed down.

  That is, according to the high-efficiency solid-state light source device described above, it is possible to realize a light source device that has high light utilization efficiency and can selectively extract light of a desired color with a narrowed diffusion angle of the light flux.

<< Light modulator (liquid crystal panel) >>
Next, the detailed structure of the light modulator (liquid crystal panel) when the above-described high-efficiency solid-state light source device is used will be described below with reference to a plurality of examples.

<Example 1>
As shown in FIG. 2 and FIG. 3 described above, the high-efficiency solid-state light source device described above is used as the light source unit 421, and white light from the light source is transmitted, for example, by a transmissive optical modulation including a TFT liquid crystal panel. The light enters the unit (liquid crystal panel) 422 and is converted into desired image light based on an image signal from the outside, and the converted image light is projected onto the Fresnel lens 425 via the projection lens 423.

  With such a configuration, it is possible to realize a head-up display device that displays desired information on the lower side of the windshield 400 with a relatively simple configuration.

<Example 2>
Next, another embodiment (Embodiment 2) of the light modulator (liquid crystal panel) will be described with reference to FIG. As shown in FIG. 11, in the second embodiment, in addition to the configuration shown in the first embodiment, the second image display is further performed so as to cover almost the entire area of the Fresnel lens 425 on the exit surface side. A liquid crystal panel 440 is attached and a second liquid crystal panel drive circuit 431 for driving the second image display liquid crystal panel 440 is provided.

  The second image display liquid crystal panel 440 performs optical modulation based on a video signal (common) from the outside via the second liquid crystal panel drive circuit 431. According to this configuration, the obtained contrast is the product of the contrast ratio of the second image display liquid crystal panel 440 and the contrast ratio of the first image display liquid crystal panel 422, and thus, in particular, due to external light. It is possible to significantly improve the contrast ratio of a display image, which is very important for a head-up display device that displays a projected image in the visual field. In other words, it is possible to obtain a sufficient contrast ratio while using relatively inexpensive panels as the first image display liquid crystal panel 422 and the second image display liquid crystal panel 440.

  Further, in such a configuration, the first image display liquid crystal panel 422 and the second image display liquid crystal panel 440 are optically modulated based on an external video signal (common) as shown by a solid line in the figure. However, as shown by a dashed arrow, by performing optical modulation based on mutually different video signals from a three-dimensional display device not shown here, it is possible to obtain the results shown in FIGS. As shown, the first image 155 displayed by the first image display liquid crystal panel 422 and the second image 175 displayed by the second image display liquid crystal panel 440 allow information to be displayed three-dimensionally (three-dimensionally). It is possible to realize a possible head-up display device.

<Example 3 and Example 4>
As shown in FIG. 13, on the emission surface side of the solid-state light source unit 421 including the above-described light reflection combining unit 20, light combining unit 30, and light source cell 40, for example, a phase difference generating unit 51 including a phase plate and the like are provided. A field lens 52 is provided, and light emitted from the solid-state light source unit 421 is converted into a first reflection type light modulation unit (for example, liquid crystal panel, reflection type liquid crystal panel, DLP) 422 by a polarization separation element 53 such as a polarization prism. After being guided upward, the reflected light modulated by the light modulator is projected by the projection lens 423 onto the Fresnel lens 425. In this example, the second light modulator 440 is also provided on the light emission side of the Fresnel lens 425.

  Alternatively, as shown in FIG. 14, the light emitted from the solid-state light source unit 421 and transmitted through the phase difference generating unit 51 and the field lens 52 is made of, for example, a resin such as acrylic, polystyrene, polycarbonate, or PET. It is also possible to employ a configuration in which a light guide 55 formed by forming a large number of sawtooth-shaped projections on the surface guides it onto a transmissive light modulator (liquid crystal panel) 422.

  In the first to fourth embodiments described above, white light in which R light, G light, and B light are mixed is extracted from the light emitting surface 35 (see FIG. 5) of the solid-state light source unit 421. Therefore, the light source cells 40a to 40d forming the light source unit are always driven by the power supply circuit (not shown).

  According to the high efficiency solid state light source device of the present invention described above, in addition to white light, R (red) light, G (green) light, and B (blue) light can be time-divided and selectively extracted. Therefore, it is also possible to employ the modulation method described in detail below, that is, the light color cyclic modulation method.

<< Light Color Circulation Modulation Method >>
It should be noted that this light color cyclic modulation method can be realized by the configuration shown in FIGS. 2 and 3, but, as shown in FIG. 15, based on an external video signal, The light from the solid-state light source unit 421 is sequentially and selectively switched to R light, G light, and B light, and the video signal to the light modulation unit 422 is changed to an R light video signal, a G light video signal, The video signal for B light is sequentially switched.

  For example, as shown in FIG. 15, the liquid crystal panel drive circuit 430 includes conversion circuits 431, 432, 433 that generate an R light video signal, a G light video signal, and a B light video signal from an input video signal. A light source cell driving power supply circuit 434 for driving the light source cell 40 is provided.

  Then, according to the configuration of the light modulator drive circuit 430 described above, as shown in FIGS. 16A to 16D, the switch circuits 435 and 436 working in synchronization with each other operate as follows. To do. That is, when the drive current from the light source cell drive power supply circuit 434 is supplied to the light source cell 40R, which is the light source of R light, through the switch circuit 436 (see FIG. 16A), the image for R light is used. The signal is output to the light modulator 422 through the switch circuit 435 (see FIG. 16D). Similarly, when the drive current from the light source cell drive power supply circuit 434 is supplied to the light source cell 40G which is the light source of G light (see FIG. 16B), the video signal for G light is switched to the switch circuit 435. It is output to the optical modulator 422 via (see FIG. 16D). Then, when the drive current from the light source cell drive power supply circuit 434 is supplied to the light source cell 40B which is the light source of B light (see FIG. 16C), the B light image signal is transmitted through the switch circuit 435. It is output to the optical modulator 422 via the light source (see FIG. 16D). The switching of the light emission color of the light source cell and the video signal for each color is performed, for example, at a cycle of 120 to 480 Hz. According to this, the light from each pixel of the liquid crystal panel is perceived by the human eye as a natural color obtained by mixing the color lights.

According to the configuration described above, the following effects can be obtained as compared with the conventional modulation method for modulating white light. That is, as shown in FIG. 17A, in the conventional modulation method for modulating white light, white light from a light source is separated and converted into R light, G light, and B light through a color filter F, for example. After that, each of them is incident on each of the corresponding liquid crystal cells C _R , C _G , and C _B of the liquid crystal panel driven by the R light image signal, the G light image signal, and the B light image signal for modulation. As a result, a desired color image is projected by the modulated R light, G light, and B light.

  On the other hand, according to the above-described light color cyclic modulation method according to the present invention, as shown in FIG. 17B, the light from the solid-state light source unit 421, which is a light source, is R light, G light, B light. Since light and light can be sequentially and selectively switched, these color lights may be sequentially incident on the liquid crystal cells C constituting the liquid crystal panel to perform modulation, and as a result, they are sequentially obtained. By projecting the image light for R light, the image light for G light, and the image light for B light, a desired color image can be obtained.

  As described above, according to the light color cyclic modulation method according to the present invention, first, white light is separated and converted into R light, G light, and B light as compared with the conventional modulation method for modulating white light. The color filter F for this purpose is unnecessary, and the absorption of light by the color filter F can be avoided. As a result, it is possible to significantly improve the utilization efficiency of the light from the light source.

In addition, in the conventional modulation method for modulating white light, three liquid crystal cells C _R , C _G , and C _B adjacent to each other in the horizontal direction of the liquid crystal panel are handled as one image unit. In the light color circulation modulation method, it is possible to handle only one liquid crystal cell C as one image unit, and therefore, it is possible to triple the resolution of the obtained image, particularly in the horizontal direction. It will be possible.

  That is, by adopting the above-described light color circulation type modulation method according to the present invention, it is possible to obtain a projected image with high light utilization efficiency and high resolution. This is very advantageous for a head-up display device that displays a projected image. Furthermore, for example, as in the second embodiment described above, a second image display liquid crystal panel may be attached to improve the contrast ratio of a display image and display a stereoscopic (three-dimensional) image. Is.

<< Specific configuration of projection lens >>
Next, a specific configuration of the so-called projection lens 423, which projects the image light from the light modulator in a tilted direction while reducing the trapezoidal distortion and enlarging it, will be described in detail below.

  18A and 18B are configuration diagrams of the projection optical system 1 that is the projection lens 423, and FIG. 19 is a ray diagram thereof. Image light emitted from the liquid crystal panel 422, which is an image display element, passes through filters as necessary, and is subjected to refraction by the coaxial lens system 2 and the free-form surface lens system 3 and reflected by the free-form surface mirror 4. After that, it is projected on the light redirecting section 424 made of a Fresnel lens sheet.

The coaxial lens system 2 is a retrofocus type including a first lens group G ₁ having a positive refractive power and a second lens group G ₂ having a negative refractive power.

The first lens group G ₁ is made of glass and has a positive refractive power, and has a lens L ₁ having a small radius of curvature toward the reduction side, a plastic aspherical lens L _2, and a glass having a positive refractive power. A biconvex lens L ₃ , a biconcave lens L ₄ made of glass and having a negative refracting power, a biconvex lens L ₅ made of glass, having a positive refracting power, and a glass The lens L ₆ is made of a biconvex lens having a positive refracting power and a small radius of curvature toward the magnifying side, and the lenses L ₃ to L ₅ form a triplet lens that is laminated.

Further, the refractive index of the lens L ₁ is larger than 1.8, a glass material having an Abbe number larger than 70 is applied to the lenses L ₃ and L ₅ , and a glass material having an Abbe number smaller than 25 is applied to the lens L _4. However, a glass material having an Abbe number smaller than 35 is applied to the lens L ₆ .

The second lens group G ₂ is made of plastic and has a negative refractive power and a meniscus-shaped aspherical lens L ₇ having a convex surface facing the reduction side, and a glass-made biconcave lens L ₇ having a negative refractive power. _8, a lens L ₉ biconvex shape with its small radius of curvature the magnification side has a positive refractive power made of glass, meniscus shape with a convex surface on the enlargement side has a negative refractive power in a plastic It is composed of the aspherical lens L ₁₀ .

Further, a glass material having an Abbe number larger than 70 is applied to the lens L _8, and a glass material having an Abbe number smaller than 35 is applied to the lens L ₉ .

The free-form surface lens system 3 is composed of a plastic meniscus lens-shaped free-form surface lens L ₁₁ having a convex surface facing the magnifying side and a plastic-made meniscus lens-shaped free-form surface lens L ₁₂ having a convex surface facing the magnifying side. is doing.

  The lens data is shown in Table 1 below, and the radius of curvature is represented by a positive sign when the center position of the radius of curvature is in the traveling direction. The surface relation distance represents the distance on the optical axis from the vertex position of each surface to the vertex position of the next surface.

  Eccentricity is the value in the Y-axis direction, tilting is rotation around the X-axis in the YZ plane, and eccentricity / tilt acts in the order of eccentricity and tilting on the relevant surface. With "normal eccentricity", eccentricity / tilt The next surface is placed at the position of the surface distance on the new coordinate system that was operated by. On the other hand, "DAR" means decenter and return, and the eccentricity and the tilt act only on that surface and do not affect the surface next.

  The glass material name PMMA is plastic acrylic.

  Table 2 below shows the free-form surface coefficients defined by Equation 1 below.

The free-form surface coefficient has a shape that is rotationally asymmetric with respect to each optical axis 9 (Z axis), and has a shape defined by a conical term component and an XY polynomial term component. For example, when X is quadratic (m = 2) and Y is cubic (n = 3), the coefficient of C ₁₉ corresponding to j = {(2 + 3) ² + 2 + 3 × 3} / 2 + 1 = 19 corresponds. The position of each optical axis of the free-form surface is determined by the amount of eccentricity / tilt in the lens data in Table 1 above.

  Table 3 below shows the aspherical surface coefficients defined by the following Expression 2.

  The aspherical coefficient has a shape that is rotationally symmetric with respect to each optical axis (Z axis), and uses the components of the conical term and the components of the 4th to 20th even degrees of the height h from the optical axis. There is.

  The odd-order polynomial aspherical coefficients shown in Table 4 below have a shape obtained by adding an odd-order component to the aspherical surface in Table 3 above. Since the height h is a positive value, it has a rotationally symmetrical shape.

In the projection optical system described above, the flange back adjustment can be performed by moving the free-form surface lens 3 which is the focusing lens, but (1) the original range of movement (adjustment range) of the focusing lens is deviated. Further, (2) it is desirable for optical performance to correct the component error of the coaxial lens system 2 with the same coaxial lens system 2. For these reasons, the first lens unit G ₁ having a positive refractive power of the coaxial lens system 2 is separated into two refractive power components. Specifically, in FIGS. 18A and 18B, by separating the lens L ₁ to the lens L ₅ and the lens L _6, and moving the lenses L ₁ to L ₅ on the optical axis. The flange back adjustment was performed.

Here, between the lens L ₅ and the lens L _6, since the arranged aperture stop 7, the lens L ₅ and the lens L _6, the sign of the ray height of the principal ray is positive and negative reversed.

Therefore, regarding the chromatic aberration of magnification, since the lens L ₅ and the lens L ₆ have different actions, the lens L ₅ has an Abbe number of 70 or more, but the lens L ₆ has an Abbe number of 35 or less.

Next, the lens configuration of the lenses L ₇ to L ₁₀ will be described.

The lenses L ₇ to L ₁₀ are lens groups having a negative refractive power in the coaxial lens system ₂ and constitute a second lens group G ₂ . Therefore, the basic structure is a concave lens and a convex lens.

The lens L ₇ is made of plastic and is an aspherical lens having a negative refracting power and a convex surface facing the reduction side, and the lens L ₈ is a biconcave glass lens having a negative refracting power and a concave surface facing the reduction side. The lens L ₉ is a biconvex glass lens having a positive refracting power and a small radius of curvature on the magnification side, and the lens L ₁₀ is a plastic lens having a negative refracting power and having a meniscus shape with a convex surface facing the magnification side. It was a spherical lens.

  That is, by applying the projection optical system described in detail above to the projection lens 423, even if the image light from the light modulator is projected in the inclined direction, the trapezoidal distortion is reduced and enlarged. Can be projected.

<< transparent screen >>
Next, the transparent screen 410, which is attached to the lower side of the windshield 400 along the inner surface thereof and is a means for displaying information by the light projected from the image display device 420, will be described below.

  Although the transparent screen 410 made of the antireflection film has been described above, other transparent screens 410 'will be described below.

FIG. 20A is a perspective view in which a part of the transparent screen 410 ′ is taken out and enlarged, and as is apparent from this figure, for example, a substrate sheet 500 made of a polyethylene terephthalate (PET) film. A large number of fine protrusions 510 each having a triangular cross section and a rectangular overall shape are formed on the surface of. Each of these protrusions 510 is set to have the following dimensions, for example, as shown in the enlarged cross section of FIG.
Length (L) = 5 to 10 μm: Horizontal (W) = 2 to 4 μm

Further, the cross-sectional shape (angle) of each protrusion 510 differs depending on the direction in which the reflected light is guided, but for example, in this example, it is set as follows.
Angle (θ _A ) = 25 to 65 degrees: Angle (θ _B ) = 65 to 25 degrees

  Furthermore, the above-mentioned protrusions 510 are formed on the surface of the substrate sheet 500 made of PET film by being arranged as shown in FIG. 21 (A) or (B) which is a front view of the screen. For example, FIG. 21A shows an example in which the protrusions 510 are arranged in a row in the horizontal direction and in the vertical direction at predetermined intervals. In some cases, unlike FIG. 21 (A), FIG. 21 (B) shows an example in which the protrusions 510 are vertically separated in a horizontal direction while being separated from each other by a predetermined distance. ..

  As described above, according to the configuration in which a large number of protrusions 510 are dispersedly arranged on the surface of the substrate sheet 500, image light incident from a predetermined angle is selectively reflected in a desired direction. At the same time, it is possible to avoid the occurrence of so-called moire fringes, which is often a problem in such a configuration.

  As described above, according to the transparent screen 410 ′ having the above-described configuration, as shown in FIG. 22, the light from the outside is transmitted and the light incident from below (see FIG. 2) is reflected at a desired angle. It is easy for the eyes 409 of the driver 407 to recognize various information necessary for driving as well as the external visual field entering through the windshield 400 and the transparent screen 410 ′ attached to the lower part thereof. In this state, it is possible to simultaneously display the images.

  Finally, FIG. 23 shows a head-up display device according to another embodiment of the present invention. That is, in FIG. 1 described above, the head-up display device in which the transparent screen 410 is attached to the windshield in advance and the image display device 420 is mounted inside the dashboard 403 has been described. For example, a head-up display device that can be installed and used on a desk or a table in a train cockpit or a training room is shown. That is, as is apparent from the drawing, the transparent screen 410, which is the display unit, is tilted at a predetermined angle by, for example, a pair of stands 411 formed in a substantially “L” shape at both left and right ends thereof. Below the transparent screen 410, an image display device 420 that includes a light source unit and projects the image light upward at a wide angle is arranged below the transparent screen 410. By 410, the light is reflected in a predetermined direction (see FIG. 1, that is, in the direction projected on the eyes 409 of the driver 407) depending on its position (height).

  It should be noted that the present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments describe the entire system in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, with respect to a part of the configuration of each embodiment, other configurations can be added / deleted / replaced.

  Further, each of the above-mentioned configurations and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit, or each of the above-mentioned configurations, functions, etc. It may be realized by software by interpreting and executing a program that realizes. Information such as a program, a table, and a file that realizes each function can be placed in a memory, a hard disk, a recording device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, and a DVD.

  400 ... Windshield, 410 ... Transparent screen, 420 ... Image display device, 407 ... Driver (driver), 409 ... Eyes, 421 ... Light source part, 422 ... Light modulation part (liquid crystal panel, reflective liquid crystal panel, DLP, etc.) ) 423 ... Projection lens, 424 ... Light direction conversion unit, 430 ... Light modulation unit drive circuit, 20 ... Light reflection synthesis unit, 30 ... Light synthesis unit, 40 ... Light source cell, 31 ... Dichroic prism, 33 ... Wavelength selective optics Surface (film), 35 ... Emitting surface.

Claims (4)

A head-up display device for displaying information including an image in a part of a driver's field of view,
The image display device is disposed at a position out of the sight of the operator and generates and projects image light for projecting the information,
As a light source forming the image display device, a solid-state light source device that reflects and mixes light emitted from a plurality of light source cells and emits in a predetermined direction is used.
The solid-state light source device is formed of a light guide body whose outer peripheral surface is covered with a reflective film and which has a parabolic surface at its tip and which has a substantially quadrangular pyramid shape, and the outer peripheral surface of which is provided with the plurality of light source cells. A head-up display device characterized in that The head-up display device according to claim 1,
The solid-state light source device of the image display device emits white light,
The image display device further magnifies the image light from the light modulator that separates the white light from the solid-state light source device into R light, G light, and B light to generate image light. A head-up display device comprising a projection optical system for projecting. An information display method in a head-up display device for displaying information including an image in a part of a driver's field of view using the image display device,
The light source constituting the image display device,
A parabolic surface is formed at the tip and the outer peripheral surface of the light guide body having a substantially quadrangular pyramid shape is covered with a reflective film,
A plurality of light source cells are mounted on the outer peripheral surface of the light guide,
Which reflects and mixes the light emitted from the plurality of light source cells to emit the light in a predetermined direction,
An information display method characterized in that the image display device generates and projects image light for projecting the information from a position outside the field of view of the operator. In the information display method described in claim 3,
The image display device emits white light from the light source, separates the white light into R light, G light, and B light to generate image light, and magnifies and projects the image light. Information display method.

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