JP2024047771A - Lighting device - Google Patents

Abstract

[Problem] To realize a compact lighting device capable of irradiating light from one light source in multiple directions and capable of arbitrarily changing the shape of each light spot. [Solution] To achieve this, the present invention has the following configuration. That is, the lighting device has a first hole 13 in which a light source 20 is arranged, a second hole 12 from which light is emitted, and a reflective curved surface 11 connecting the first hole 13 and the second hole 12, a line connecting the center of the first hole 13 and the center of the second hole 12 is a first direction, a first reflector 10 that emits light in the first direction, a polygonal pyramid 30 having a bottom surface and multiple inclined surfaces is arranged so that the multiple inclined surfaces face the second hole 12 of the first reflector 10, the multiple inclined surfaces of the polygonal pyramid 30 are reflective surfaces, and on the reflective surface, the light traveling in the first direction changes course to a second direction intersecting the first direction, and a liquid crystal lens 100 is arranged in the second direction. [Selected Figure] Fig. 4

Description

The present invention relates to a lighting device that can emit light spots of any shape in multiple azimuth directions.

Indoors, for example, there is a demand for lighting devices attached to the ceiling to emit light horizontally, i.e., toward the wall, rather than vertically, i.e., toward the floor, to provide indirect lighting. On the other hand, in parks and other places, there is a demand for lighting devices to emit light toward the side, to be used as lighting within the park.

Patent document 1 describes a configuration that uses one light source to uniformly irradiate the entire periphery of the lighting device. Patent document 2 describes a configuration that uses multiple light sources to uniformly irradiate the periphery of the lighting device.

JP 2006-12588 A JP 2015-167086 A

Conventional technology can emit light uniformly to the sides of the lighting device, but cannot accommodate a configuration that irradiates light spots of any shape in multiple lateral directions.

The objective of the present invention is to realize an illumination device that can form light spots of any shape in multiple azimuth directions using a single light source. Another objective of the present invention is to realize such an illumination device in a compact size.

The present invention aims to solve the above problems, and the main specific means are as follows:

(1) A lighting device comprising: a first hole in which a light source is disposed, a second hole from which light is emitted, and a reflective curved surface connecting the first hole and the second hole; a first reflector that emits light in the first direction, a polygonal pyramid having a base and multiple inclined surfaces that are disposed so that the multiple inclined surfaces face the second hole of the first reflector, the multiple inclined surfaces being reflective surfaces; light traveling in the first direction changes course on the reflective surface to a second direction that intersects with the first direction; and a liquid crystal lens is disposed in the second direction.

(2) The lighting device described in (1) is characterized in that the polygonal pyramid is a quadrangular pyramid.

(3) The lighting device described in (1), characterized in that the crossing angle between the first direction and the second direction is 90 degrees.

FIG. 2 is a side view of an illumination device that emits collimated light. 2 is a plan view of the lighting device of FIG. 1 for emitting light in four directions. FIG. FIG. 2 is a perspective view showing a part of the lighting device of the present invention. FIG. 1 is a perspective view showing a lighting device according to a first embodiment. 4 is a cross-sectional view showing the operation of the first embodiment. FIG. FIG. 2 is a plan view of the first embodiment. FIG. 2 is a perspective view of a funnel-type reflector. FIG. 2 is a perspective view of a square pyramid reflector. 1 is a cross-sectional view showing the relationship between a quadrangular pyramid reflector and a liquid crystal lens. 5A to 5C are cross-sectional views illustrating the operation of a liquid crystal lens. 11 is another cross-sectional view illustrating the operation of the liquid crystal lens. FIG. 11 is yet another cross-sectional view illustrating the operation of the liquid crystal lens. FIG. FIG. 2 is a cross-sectional view of a first liquid crystal lens. FIG. 4 is a plan view showing the electrode shape of the first liquid crystal lens. 4A and 4B are perspective views showing the operation of a first liquid crystal lens and a second liquid crystal lens. 4 is a cross-sectional view showing a state in which a first liquid crystal lens and a second liquid crystal lens are laminated. FIG. 4 is a perspective view showing the operation of a first liquid crystal lens, a second liquid crystal lens, a third liquid crystal lens, and a fourth liquid crystal lens. FIG. FIG. 1 is a diagram illustrating an operation of the first embodiment. This is the shape of the light spot projected onto the liquid crystal lens in the configuration of FIG. FIG. 11 is a diagram illustrating the operation of the second embodiment. This is the shape of the light spot projected onto the liquid crystal lens in the configuration of FIG. 4 is a table showing various functions of the liquid crystal lens according to the first embodiment. FIG. 11 is a plan view showing another example of the liquid crystal lens. FIG. 24 is a plan view of a lens element of the liquid crystal lens in FIG. 23. FIG. 24 is a cross-sectional view of the liquid crystal lens of FIG. 23. 13 is a chart showing a case where the liquid crystal lens is driven in a time-division manner. FIG. 13 is a diagram illustrating the operation of the third embodiment. This is the shape of the light spot projected onto the liquid crystal lens in the configuration of FIG. FIG. 2 is a cross-sectional view of a liquid crystal light valve. FIG. 11 is a perspective view of a funnel-type reflector according to a fourth embodiment. 31 is a plan view of the funnel-type reflector of FIG. 30 viewed from above. FIG. This is a cross-sectional view taken along the line CC of Figure 30. FIG. 13 is a diagram illustrating the operation of the fourth embodiment. This is the shape of the light spot projected onto the liquid crystal lens with the configuration of FIG. FIG. 13 is a diagram illustrating an operation when the fourth embodiment is combined with the second embodiment. This is the shape of the light spot projected onto the liquid crystal lens with the configuration of FIG.

The present invention will be described in detail below using examples.

Figure 1 is a side view of a lighting device 1 that emits collimated light in a predetermined direction. In Figure 1, an optical component 2 such as a lens is disposed at the tip of the vertically elongated lighting device 1, and light is emitted from the optical component 2 such as a lens. The collimated light has a predetermined orientation angle θ.

Lighting devices 1 for obtaining collimated light often use parabolic curved mirrors. In such lighting devices 1, in order to reduce the light distribution angle θ of the emitted light 4, it is necessary to increase the length h1 of the lighting device 1. Also, in order to obtain a specified light spot, it is necessary to arrange optical components such as corresponding lenses.

Figure 2 is a plan view of the case where light having an arbitrary spot shape is emitted in four lateral directions. In Figure 2, the lighting device 1 shown in Figure 1 is placed horizontally with an azimuth angle of 90 degrees. With the lighting device set in Figure 2, an arbitrary light spot can be formed in four directions, but as shown in Figure 2, the planar diameters x1 and y1 of the lighting device set become large. Also, as described in Figure 1, if collimated light is to be obtained, the length h1 of the lighting device 1 becomes large, and as a result, the horizontal diameters x1 and y1 of the lighting device set become even larger.

Figure 3 is a perspective view showing a part of a lighting device according to the present invention that solves such problems. In Figure 3, a funnel-type reflector 10 that emits collimated light is placed on a base 3. The funnel-type reflector 10 has a rectangular parallelepiped exterior and a parabolic curved reflective surface 11 formed on the interior wall. An LED 20 is placed in a hole 13 formed in the bottom surface of the funnel-type reflector 10. Light from the LED 20 is reflected by the parabolic curved surface 11 and emitted from the emission hole 12.

Corresponding to the exit hole 12, the pyramidal reflector 30 is arranged with its reflective surface facing downward, i.e., facing the exit hole 12. The four reflective surfaces of the pyramidal reflector 30 are triangles with apex angles of 90 degrees. The apex of the pyramidal reflector 30 coincides with the central axis of the funnel-type reflector 10, i.e., the optical axis. Therefore, the collimated light emitted from the exit hole 12 of the funnel-type reflector 10 is reflected by the four faces of the pyramidal reflector 30 and emitted in four directions.

In FIG. 3, the outer shape of the funnel-type reflector 10 is a rectangular parallelepiped, with a height zf of about 20 mm and widths xf and yf of, for example, about 10 mm. The base 3 only needs to be tall enough to accommodate the LED board, so a height zb of, for example, about 3 mm is sufficient. On the other hand, if one side of a pyramidal reflector is 10 mm, then the height will be about 3.5 mm. Therefore, the structure in FIG. 3 has a very compact outer shape with a cross section of a square with one side of 10 mm and a height of 30 mm or less. Collimated light can be emitted in four directions from such a compact lighting device.

The structure in Figure 3 can emit a predetermined collimated light in four predetermined directions, but the shape of the emitted light cannot be changed. In Example 1, the structure in Figure 3 is configured such that a liquid crystal lens 100 acts on the light reflected by the pyramidal reflector 30. Figure 4 is a perspective view showing this configuration.

In FIG. 4, a liquid crystal lens 100 is arranged with a main surface perpendicular to the optical path of the light reflected by the quadrangular pyramid reflector 30. In FIG. 4, the liquid crystal lens 100 is depicted as being a transparent sheet in order to show the positional relationship. In reality, the liquid crystal lens 100 is composed of thin liquid crystal lenses stacked together, but in FIG. 4, it is depicted as being a single transparent sheet in order to avoid complicating the drawing.

Figure 5 is a cross-sectional view taken along line A-A in Figure 4. Figure 5 is a cross-sectional view showing the operation of Example 1. In Figure 5, a reflective surface 11 with a parabolic curved sidewall is formed inside a funnel-type reflector 10 whose external shape is a rectangular parallelepiped. An LED 20 is disposed in an LED hole 13 formed in the bottom surface of the funnel-type reflector 10. The LED 20 is disposed on an LED board 21, which is housed in a base 3.

In FIG. 5, the light emitted from the LED 20 is reflected by the parabolic curved surface 11 and travels from the exit hole 12 toward the pyramid reflector 30, where its optical path is bent by 90 degrees at the reflecting surface of the pyramid reflector 30 and travels horizontally (in the x direction). The light that has changed course horizontally enters the liquid crystal lens 100 and is subjected to the lens action.

When liquid crystal lens 100 does not act as a lens, the light travels straight in the horizontal direction. However, when liquid crystal lens 100 acts as a diverging light, the light diverges as shown by the dotted lines in Figure 5. As will be described later, liquid crystal lens 100 can electrically perform lens functions of various shapes, so it is easy to obtain light spots of various shapes.

Figure 6 is a plan view of Figure 4 viewed from above. In Figure 10, a pyramidal reflector 30 is placed with its convex portion facing downwards on top of a funnel-type reflector 10 whose outer planar shape is a square and which has a circular emission hole 12 formed inside. In a plan view, four liquid crystal lenses 100 are placed on either side of the pyramidal reflector 30. In Figure 6, the light emitted from the funnel-type reflector 10 is emitted horizontally with an azimuth angle of 90 degrees to each other. The diameters x2 and y2 of the plane in Figure 6 can be made smaller than x1 and y1 in Figure 2.

Figure 7 is a perspective view of the funnel-type reflector 10. The outer shape of the funnel-type reflector 10 is a rectangular parallelepiped. Inside the rectangular parallelepiped, a funnel-shaped recess is formed, and the wall surface of the recess is a parabolic curved surface 11. The shape of this recess is a circle on the x-y plane, and the cross section in the z-axis direction is a parabolic curved surface. The parabolic curved surface collimates the light in a direction parallel to the z-axis. Note that the wall surface of the recess may be partially configured as a parabolic curved surface.

In FIG. 7, a hole 13 for an LED 20 is formed on the bottom surface of the rectangular parallelepiped. Small LEDs measuring approximately 1.5 mm square in plan view are also commercially available. The LED hole 13 only needs to have enough space to accommodate such a small LED. An emission hole 12 is formed on the top surface of the rectangular parallelepiped. The emission hole 12 is, for example, a circle with a diameter dd of approximately 6.5 mm.

The LED hole 13 and the emission hole 12 are connected by a parabolic curved surface 11. The light emitted from the LED 20 is collimated by the parabolic curved surface 11 and emitted from the emission hole 12. In FIG. 6, the larger the ratio (hf/dd) of the diameter dd of the emission hole 12 to the height of the funnel-type reflector 10, the more collimated the light, that is, the smaller the emission angle of the emitted light, can be obtained. (hf/dd) is sometimes called the aspect ratio.

The aspect ratio is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. In the configuration of the present invention shown in Figure 4, the funnel-type reflector 10 is used in a vertical orientation, so even if the aspect ratio is increased, it does not affect the horizontal width of the lighting device.

Figure 8 is a perspective view of the pyramidal reflector 30. In Figures 3, 4, and 5, the pyramidal reflector 30 is depicted as if it is floating in the air in order to avoid complicating the figures, but in reality, it is supported by supports 31 placed at the corners of the pyramidal reflector 30. Each support 31 is placed near a corner on the light output surface side of the funnel-type reflector 10. Since light does not enter the corners of the pyramidal reflector 10, there is space to place the supports 31 as shown in Figure 8.

Figure 9 is a cross-sectional view showing the path of light near the pyramidal reflector 30 and the liquid crystal lens 100. In Figure 9, light from the funnel-type reflector 10 side is reflected by the reflecting surface of the pyramidal reflector 30 and enters the liquid crystal lens 100. In Figure 9, the light that enters the liquid crystal lens 100 is subjected to a diverging effect and exits from the liquid crystal lens.

In FIG. 9, liquid crystal lens 100 is composed of four liquid crystal lenses 110, 120, 130, and 140. Each liquid crystal lens acts on light with a different polarization. Each liquid crystal lens is composed of a TFT substrate on which wiring is formed and an opposing substrate, but since the thickness of the TFT substrate and the opposing substrate is about 0.5 mm each, the thickness of each liquid crystal lens is about 1 mm. Therefore, even if four lenses are used, the total thickness of the liquid crystal lenses is about 4 mm. In addition, since the light spot incident on the liquid crystal lens is very small, it is sufficient for the outer shape of the liquid crystal lens to be about 10 mm on one side.

Figure 10 is a cross-sectional view showing the principle of the liquid crystal lens 100. In Figure 10, collimated light is incident from the left side of the liquid crystal layer 300. P in Figure 10 means the deflection direction of the incident light. The deflection direction of normal light is randomly distributed, but since liquid crystal has anisotropy in the refractive index, Figure 7 shows the effect on light deflected in the P direction.

In FIG. 10, the liquid crystal molecules 301 in the liquid crystal layer 300 are aligned by the electrodes so that the inclination increases toward the periphery of the liquid crystal layer 300. The liquid crystal molecules 301 are elongated, and the effective refractive index in the long axis direction of the liquid crystal molecules 301 is greater than the effective refractive index in the short axis direction of the liquid crystal molecules 301. As a result, the refractive index increases toward the periphery of the liquid crystal layer 300, forming a convex lens. The dotted line in FIG. 10 represents the light wavefront WF, and f is the focus distance of the lens.

Since liquid crystals have anisotropic refractive index, to form a lens, a second lens is required that acts on light polarized in a direction perpendicular to the direction of polarization of the light that the first lens acts on. Figure 11 is an exploded perspective view showing this lens configuration. In Figure 11, the parallelogram on the left is the wavefront of the light. In other words, light polarized in the X and Y directions enters the liquid crystal layer 300. The first liquid crystal lens 110 is a lens that acts on X-polarized light, and the second liquid crystal lens 120 is a lens that acts on Y-polarized light.

In FIG. 11, the initial alignment directions of the liquid crystal molecules 301 differ by 90 degrees between the first liquid crystal lens 110 and the second liquid crystal lens 120. The initial alignment of the liquid crystal molecules 301 is determined by the alignment direction of the alignment film in the liquid crystal lens. In other words, in FIG. 11, the alignment directions of the alignment films on the substrates on the light-incident side of the two liquid crystal lenses 110 and 120 are perpendicular to each other.

Figure 12 shows the case where a concave lens is formed by a liquid crystal lens. In Figure 12, the wavefront WF is parallel to the liquid crystal layer 300, and light polarized in one direction enters the liquid crystal layer 300 from the left side. In Figure 12, the liquid crystal molecules 301 in the liquid crystal layer 300 are most strongly oriented near the optical axis by the electrodes, and the orientation angle becomes smaller toward the periphery. With this lens configuration based on liquid crystal orientation, the wavefront WF of the light that has passed through the liquid crystal layer 300 becomes a curve as shown by the dotted line in Figure 12, and a concave lens is formed. Note that in the case of a concave lens, two liquid crystal lenses are still required, as shown in Figure 11.

Figure 13 is a detailed cross-sectional view of the liquid crystal lens 110. In Figure 13, a first electrode 112 is formed on the TFT substrate 111, and a first alignment film 113 is formed covering the first electrode 112. The alignment direction of the first alignment film 113 determines which polarized light of the incident light is acted upon by the liquid crystal lens. A second electrode 116 is formed on the inner side of the counter substrate 115, and a second alignment film 117 is formed covering the second electrode 116. The relationship between the alignment direction of the first alignment film 113 and the alignment direction of the second alignment film 117 is determined by the type of liquid crystal used. A liquid crystal layer 300 is sandwiched between the TFT substrate 111 and the counter substrate 115.

The left side of FIG. 14 is a plan view of the first electrode 112 formed on the first substrate 111. The first electrodes 112 are concentric circles. An extraction wiring 114 for applying a voltage is connected to each circular electrode 112. The right side of FIG. 21 is a plan view showing the shape of the second electrode 116 formed on the opposing substrate 115. The second electrode 116 is a flat electrode, and is formed over almost the entire surface of the opposing substrate 115.

In FIG. 14, lenses of various strengths can be formed by changing the voltage between the first electrode 112 and the second electrode 116. The examples in FIG. 13 and FIG. 14 have the feature that circular lenses can be easily formed because the first electrode 111 is formed in a concentric circle.

The liquid crystal lens 110 described in Figures 13 and 14 is a lens that acts in one direction, for example polarized light PX. However, since the light from the LED 10 is polarized in all directions, a liquid crystal lens that acts at least on light PY polarized in a direction perpendicular to PX is required.

Figure 15 is a perspective view showing this configuration. In Figure 15, when light LL from the LED enters from the left side, light polarized in the PX direction by the first liquid crystal lens 110 is subjected to the action of the liquid crystal lens. Light polarized in the PY direction is not affected by the first liquid crystal lens 110. Light polarized in the PY direction is subjected to the action of the liquid crystal lens by the second liquid crystal lens 120. Light polarized in the PX direction is not subjected to the action of the second liquid crystal lens 120. This allows both light polarized in the x direction and light polarized in the y direction to be subjected to the action of the liquid crystal lens.

Figure 16 is a cross-sectional view showing the state in which the first liquid crystal lens 110 and the second liquid crystal lens 120 are laminated. The first liquid crystal lens 110 and the second liquid crystal lens 120 are bonded with a transparent adhesive 200. In Figure 16, the electrode configuration of the second liquid crystal lens 120 is the same as that of the first liquid crystal lens 110. That is, in the second liquid crystal lens 120, a third electrode 122 is formed on the TFT substrate 121, and a third alignment film 123 is formed thereon. A fourth electrode 126 is formed on the opposing substrate 125, and a fourth alignment film 127 is formed thereon.

The second liquid crystal lens 120 differs from the first liquid crystal lens 110 in the orientation direction of the orientation film 123. In FIG. 16, AL indicates the orientation direction of the orientation film 113. In FIG. 16, the orientation direction of the first orientation film 113 formed on the TFT substrate 111 of the first liquid crystal lens 110 is, for example, the x direction. The orientation direction of the third orientation film 123 formed on the TFT substrate 121 of the second liquid crystal lens 120 is, for example, the y direction. In other words, both light polarized in the x direction and light polarized in the y direction can be acted upon by the two liquid crystal lenses 110 and 120.

The orientation direction of the second alignment film 117 formed on the opposing substrate 115 of the first liquid crystal lens 110 and the orientation direction of the fourth alignment film 127 formed on the opposing substrate 125 of the second liquid crystal lens 120 are determined by the type of liquid crystal used as the liquid crystal 300. In other words, the second alignment film 117 of the first liquid crystal lens 110 may be oriented in the same direction as the first alignment film 113, or may be oriented at a right angle. The relationship between the third alignment film 123 and the fourth alignment film 127 of the second liquid crystal lens 120 is also the same.

However, since the light from the LED 10 is polarized in all directions, the liquid crystal lens may not be effective enough if it acts only on PX or PY polarized light. In this case, as shown in Figure 17, for example, it is sufficient to add a liquid crystal lens 130 that acts on light P45 that is polarized at 45 degrees to the x direction, and a liquid crystal lens 140 that acts on light P135 that is polarized at 135 degrees to the x direction.

As described above, the configuration of Example 1 makes it possible to emit collimated light in four directions using a very compact lighting device. Furthermore, the shape of the irradiated light can be changed as desired.

Figure 18 is a cross-sectional view and a plan view for explaining the shape of the light spot in the lighting device described in Example 1. The top left diagram in Figure 18 is a view of the pyramidal reflector 30 as seen from the bottom. That is, on the top left side, the pyramidal reflector 30 is placed so that its apex is at the top of the page. The shaded circle 4 above the pyramidal reflector 30 shows the state in which a circular light spot from the funnel-type reflector 10 is irradiated onto the triangular reflecting surface of the pyramidal reflector 10. In Figure 18, a cross-sectional view of the funnel-type reflector 10 that emits light with a circular cross section is shown below the pyramidal reflector 30.

When viewed in a plan view, the spot irradiated onto the entire pyramidal reflector 30 is circular, but the shape of the light spot reflected from the reflective surface of each pyramidal reflector 30 is irregular. The shape of the light spot projected onto the liquid crystal lens 110 in FIG. 18, i.e., the light spot viewed from direction A in FIG. 18, is fan-shaped as shown in FIG. 19. If the liquid crystal lens 100 were a diffusing lens, the shape of the light spot irradiated onto the irradiation surface would be an enlarged fan shape as shown in FIG. 19.

Depending on the application of the lighting device, there are many cases where the light irradiation shape shown in FIG. 19 is not a problem. On the other hand, there are cases where a simple shape such as a rectangle is required for the irradiation spot. Although the liquid crystal lens 100 can diverge the light beam, it is difficult to change the light spot shape from an irregular shape to a simple shape such as a rectangle. Therefore, in the second embodiment, a stop (also called an aperture) 40 is placed before the light reflected from the pyramidal reflector 30 enters the liquid crystal lens 100, and the light spot shape is shaped, for example, into a rectangle before it enters. If the light spot shape is simple such as a rectangle, it is possible to change the light spot shape using the liquid crystal lens 100.

Figure 20 is a diagram showing the operation of such an illumination device. Figure 20 is a diagram for explaining the shape of the light spot, but differs from Figure 18 in that an aperture 40 is placed in front of the liquid crystal lens 100, making it possible to shape the light entering the liquid crystal lens 100 into, for example, a rectangle. In Figure 20, the aperture 40 is placed at a distance from the liquid crystal lens 110, but it may also be attached to the liquid crystal lens.

Figure 21 is a diagram showing the shape of the light spot when light from the square pyramid reflector 30 enters the aperture 40 and liquid crystal lens 100. In Figure 21, the spot shape 5 of the light entering the aperture 40 is fan-shaped, the same as in Figure 19. The incident light is shaped by the aperture 40 into a rectangle 6 shown by a solid line. This rectangular light spot 6 is formed on the liquid crystal lens 100.

Figure 22 shows examples of when a rectangular light spot 6 incident on a liquid crystal lens is changed into various shapes to become illumination light 7. 22A shows the case where the rectangular light spot 6 is diffused as a whole. 22B shows an example where the rectangular light spot 6 is expanded only in the horizontal direction. 22C shows an example where the rectangular light spot 6 is expanded only in the vertical direction. 22D shows an example where the rectangular light spot 6 is expanded to have a cross shape.

22A can be handled by the lens configuration in FIG. 14, but 22B, 22C, 2D, etc. cannot be handled by the lens configuration in FIG. 14. FIG. 23 is a plan view of a liquid crystal lens 110 that can have such an effect. In FIG. 23, the TFT substrate 111 and the opposing substrate 115 are bonded at their peripheries with a sealant 150, and liquid crystal is sealed inside. The area where the TFT substrate 111 and the opposing substrate 115 overlap becomes the lens area 170.

The TFT substrate 111 is formed to be larger than the opposing substrate 115, and the portion of the TFT substrate 111 that does not overlap with the opposing substrate 115 is the terminal region 160. The driver IC 165 that drives the liquid crystal lens and other components are arranged in the terminal region 160.

In the lens region 170 in FIG. 23, the scanning lines 151 extend in the horizontal direction (x direction) and are arranged in the vertical direction (y direction). Furthermore, the signal lines 152 extend in the vertical direction and are arranged in the horizontal direction. A lens element 153 including a lens element electrode (hereinafter simply referred to as an element electrode) is formed in the region surrounded by the scanning lines 151 and the signal lines 152. A voltage is applied between the element electrode and a common electrode formed on the opposing substrate to orient the liquid crystal molecules in the required direction and refract light.

Figure 24 is a plan view of the lens element 153. In Figure 24, an element electrode 154 is formed in an area surrounded by a scanning line 151 and a signal line 152. A TFT (Thin Film Transistor) that is switched by a scanning signal is formed between the element electrode 154 and the signal line 152. The TFT is formed of a gate electrode 210 branched from the scanning line 151, a semiconductor film 211, a drain electrode 212 branched from the signal line 153, and a source electrode 123, and the source electrode 213 is connected to the element electrode 154 via a through hole 214. The other liquid crystal lenses 120, 130, and 140 have a similar configuration.

Figure 25 is a cross-sectional view of a liquid crystal lens. In Figure 25, a liquid crystal layer 300 is sandwiched between a TFT substrate 111 on which an element electrode 154 is formed and a counter substrate 115 on which a common electrode 155 is formed. The TFT substrate 111 and the counter substrate 115 are bonded with a sealant 150. A liquid crystal lens element 153 is formed between the element electrode 154 and the common electrode 155. The TFT substrate 111 is formed larger than the counter substrate 115, and the portion of the TFT substrate 111 that does not overlap with the counter substrate 115 is a terminal region 160, in which a driver IC 165 is arranged.

The liquid crystal lens shown in Figures 23 to 25 has lens elements 153 arranged in a matrix, so it can expand the incident light in any direction. In other words, if the light incident on the liquid crystal lens is diverged only in the horizontal direction, a light spot like that shown in 22B of Figure 22 is obtained, and if the light incident on the liquid crystal lens is diverged only in the vertical direction, a light spot like that shown in 23B of Figure 22 is obtained.

However, it is difficult to obtain a cross-shaped light spot as shown in FIG. 22D using the liquid crystal lens 100 using a similar method. Therefore, to obtain a light spot as shown in FIG. 15, the horizontally elongated light spot of FIG. 22B and the vertically elongated light spot of FIG. 22C can be displayed in a time-division manner. FIG. 26 is an example of time-division driving for obtaining a cross-shaped light spot. As shown in FIG. 26, a horizontally elongated spot is displayed during the first T1, and a vertically elongated spot is displayed during the following T1. T1 can be selected so that flicker is not noticeable. On the other hand, if the aperture shape is made cross-shaped, a light spot of 26D can be easily obtained with the lens configuration of FIG. 14.

The liquid crystal lenses of Figures 23 to 25 can be used to form not only divergent or convergent lenses, but also lenses that deflect light in one direction. For example, by increasing the orientation direction of the liquid crystal molecules in each element 153 of Figure 23 from left to right or from right to left, incident light can be deflected in the left and right directions.

In the second embodiment, the light spot incident on the liquid crystal lens 100 is shaped by the diaphragm 40. However, when changing the light spot shape, the diaphragm 40 must be replaced. Also, it is necessary to prepare diaphragms 40 with various openings according to the light spot shape.

In the third embodiment, the shape of the light spot incident on the liquid crystal lens 100 is shaped by the liquid crystal light valve 400. By using the liquid crystal light valve 400, the shape of the light spot incident on the liquid crystal lens 100 can be made to be any shape. The liquid crystal light valve 400 has the same basic configuration as the liquid crystal display device. Alternatively, it can be said that it is the same as the liquid crystal lens described in Figures 23 to 25.

Figure 27 is a diagram for explaining the shape of the light spot in Example 3, but differs from Figure 20 in that a liquid crystal light valve 400 is placed in front of the liquid crystal lens 100 instead of an aperture 40. In Figure 27, the liquid crystal light valve 400 is placed at a distance from the liquid crystal lens 110, but it may be attached to the liquid crystal lens 100.

Figure 28 is a plan view showing the shape of the light spot when the liquid crystal light valve 400 is used. A sector-shaped light spot 4 is incident on the liquid crystal lens 100, which is narrowed down to a rectangle 6 by the liquid crystal light valve. In Figure 28, the reflected light from the square pyramid reflector 30 is incident on the liquid crystal light valve 400 as a sector-shaped light spot 4, but is reshaped by the liquid crystal light valve 400 into a rectangle 6 and is emitted toward the liquid crystal lens 100.

The liquid crystal light valve 400 has the same basic structure as the liquid crystal lens described in Figures 23 to 25. Figure 29 is a cross-sectional view of the liquid crystal light valve 400. Unlike the liquid crystal lens 100 described in Figures 23 to 25, the liquid crystal light valve 400 requires a lower polarizing plate 420 and an upper polarizing plate 430. This is because the liquid crystal in the liquid crystal light valve 400 acts only on polarized light.

In other words, the light that passes through the upper polarizing plate 430 in FIG. 29 is polarized. Therefore, by controlling the alignment film of the liquid crystal lens 100 so that it acts on the polarized light that passes through the upper polarizing plate 430, the liquid crystal lens 100 can exert a lens effect with just one liquid crystal lens.

The problem with the third embodiment is that the light transmittance is reduced to nearly half by the polarizing plates 420 and 430 attached to the liquid crystal light valve 400. However, the reduction in transmitted light can be mitigated by using a reflective polarizing plate as the polarizing plate.

In the funnel-type reflector 10 used in Examples 1 to 3, the cross section of the reflective surface 11 formed inside is a circle, as shown in FIG. 7. The circular light emitted from such a funnel-type reflector 10 has low utilization efficiency at each reflective surface of the square pyramid reflector 30, as shown in FIG. 18, etc. In particular, the utilization efficiency is low near the four corners when the square pyramid reflector 30 is viewed in a plane.

If the shape of the light from the funnel-type reflector 10 is rectangular, as shown in FIG. 33, the utilization efficiency of the reflecting surface of the pyramidal reflector 30 can be increased. In particular, the utilization efficiency can be increased near the four corners of the pyramidal reflector 30 when viewed in a plane.

Figure 30 is a perspective view of a funnel-type reflector 15 for supplying rectangular incident light to a square pyramid reflector 30. The funnel-type reflector 15 in Figure 30 differs from the funnel-type reflector 10 in Figure 7 in that the opening 17 and LED hole 18 of the funnel-type reflector 15 are rectangular. Furthermore, the cross section of the reflective curved surface 16 is also rectangular. This allows the shape of the light emitted from the funnel-type reflector 15 to be rectangular.

Figure 31 is a plan view of the funnel-type reflector 15 of Figure 30 viewed from above. As shown in Figure 31, the opening 17 of the funnel-type reflector 15 is rectangular, and the emitted light has a shape corresponding to this rectangle. Figure 32 is a CC cross-sectional view of the funnel-type reflector 15 of Figure 30. The LED hole 18 and the opening 17 are connected by a curved surface 16, at least a portion of whose cross section is parabolic. As a result, collimated light with a rectangular cross section is emitted from the emission hole 17.

The aspect ratio, which is the ratio of the height of the funnel-type reflector 15 to the diameter of the emission hole 17, can be defined as follows: if the emission hole 17 is a square, it is hf/(dx or dy); if the emission hole 17 is a rectangle, it is hf/(dx or dy, whichever is larger). The aspect ratio is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more.

Figure 33 shows how light 4 with a rectangular cross section is irradiated onto a pyramidal reflector 30 using a funnel-type reflector 15 like that shown in Figure 30, and how the light 4 is reflected from the reflective surface of the pyramidal reflector 30 towards the liquid crystal lens 100. Comparing Figure 33 with Figure 18, the utilization efficiency of the reflective surface of the pyramidal reflector 30 in Figure 33 is greater. As a result, more light is incident on the liquid crystal lens, resulting in a brighter light spot.

Figure 34 shows the spot shape of light reflected from the pyramidal reflector 30 and incident on the liquid crystal lens 100. That is, it is the shape of the light spot when viewed from the direction of the white arrow A in Figure 33. The shape of the light spot 5 is triangular, and corresponds approximately to the reflecting surface of the pyramidal reflector 30. The area of this triangle is larger than the area of the sector in Figure 19 in Example 1.

Figure 35 is a diagram of the present embodiment applied to Example 2. This embodiment can be used as is even when the aperture 40 is used. Figure 36 shows the shape of the light spot 5 incident on the aperture 40 and the diameter of the light spot 6 after passing through the aperture 40 when the aperture 40 is placed. This is as explained in Example 2. The same applies to the combination of Example 3 and this embodiment, and the configuration of Example 3 can be applied as is.

In the first to fourth embodiments, a quadrangular pyramid reflector is used, but the reflector does not have to be limited to a quadrangular pyramid. For example, a triangular pyramid, a pentagonal pyramid, a hexagonal pyramid, or other reflector can be used. A triangular pyramid has three reflecting surfaces, a pentagonal pyramid has five reflecting surfaces, and a hexagonal pyramid has six reflecting surfaces. The corresponding liquid crystal lenses are arranged corresponding to the reflecting surfaces. Therefore, the liquid crystal lenses are arranged at intervals of 120 degrees, 72 degrees, and 60 degrees in azimuth angle, respectively. In other words, if the number of angles of the polygonal pyramid is n, the liquid crystal lenses are arranged at intervals of 360/n degrees in azimuth angle. However, only one funnel-type reflector is required to supply light to the polygonal pyramid reflector. The operation of each reflecting surface is the same as that described in the first to fourth embodiments.

In Examples 1 to 4, the light emitted from the funnel-type reflector has its optical path bent by 90 degrees by the pyramid reflector, but depending on the requirements of the optical device, it may deviate slightly from 90 degrees. However, the basic operation is the same as that described in Examples 1 to 4.

1...Illumination device, 2...Optical component, 3...Base, 4...Light emitted from funnel-type reflector, 5...Light spot, 6...Light spot after diaphragm, 7...Light spot subjected to lens action, 10...Funnel-type reflector, 11...Parabolic reflecting surface, 12...Aperture, 13...LED hole, 15...Rectangular funnel-type reflector, 16...Parabolic reflecting surface, 17...Aperture, 18...LED hole, 20...LED, 21...LED substrate, 30...Square pyramid reflector, 31...Support, 35...Square pyramid frustum reflector, 36...Reflecting surface, 37...Flat portion, 40...Aperture, 100...Liquid crystal lens, 110...First liquid crystal lens, 111...TFT substrate, 112...First electrode, 113...First alignment film, 114...Lead wiring, 115...Counter substrate, 116: second electrode; 117: second alignment film; 120: second liquid crystal lens; 121: TFT substrate; 122: third electrode; 123: third alignment film; 125: opposing substrate; 126: fourth electrode; 127: fourth alignment film; 150: sealing material; 151: scanning line; 152: signal line; 153: lens element; 154: element electrode; 155: common electrode; 160: terminal area; 165: driver IC; 170: lens area; 210: gate electrode; 211: semiconductor film; 212: drain electrode; 213: source electrode; 214: through hole; 300: liquid crystal layer; 301: liquid crystal molecule; 400: liquid crystal light valve; 411: TFT substrate; 412: pixel electrode; 415: opposing substrate; 416...common electrode, 420...lower polarizing plate, 430...upper polarizing plate

Claims (13)

a first reflector having a first hole in which a light source is disposed, a second hole from which light is emitted, and a reflective curved surface connecting the first hole and the second hole, the first direction being a line connecting the center of the first hole and the center of the second hole, and emitting light in the first direction;
a polygonal pyramid having a base and a plurality of inclined surfaces is disposed so that the plurality of inclined surfaces face the second hole of the first reflector;
the plurality of inclined surfaces are reflective surfaces, and at the reflective surfaces, the light traveling in the first direction is changed in a direction to a second direction intersecting the first direction;
A lighting device, further comprising a liquid crystal lens disposed in the second direction. The lighting device according to claim 1, characterized in that the polygonal pyramid is a quadrangular pyramid. The lighting device according to claim 1, characterized in that the crossing angle between the first direction and the second direction is 90 degrees. The lighting device according to claim 1, characterized in that the liquid crystal lenses are arranged to correspond to all of the second inclined surfaces. The first reflector has a rectangular parallelepiped outer shape,
The first hole is formed in a first surface of the rectangular parallelepiped,
the second hole is formed in a second surface of the rectangular parallelepiped that faces the first surface,
the first hole is smaller than the second hole;
The lighting device according to claim 1 , wherein at least a part of a curved surface connecting the first hole and the second hole is a parabolic curved surface. The lighting device of claim 1, characterized in that the second hole of the first reflector is circular. The lighting device according to claim 1, characterized in that the second hole of the first reflector is rectangular. The lighting device according to claim 6, characterized in that in the first reflector, the ratio of the diameter of the second hole to the distance between the first surface and the second surface of the first reflector is 2 or more. the second hole in the first reflector is square;
8. The lighting device according to claim 7, wherein a ratio of a side length of the second hole to a distance between the first surface and the second surface of the first reflector is 2 or more. The lighting device according to claim 1, characterized in that an aperture is disposed between the liquid crystal lens and the second reflector. The lighting device according to claim 1, characterized in that a liquid crystal light valve is disposed between the liquid crystal lens and the second reflector. The lighting device according to claim 1, characterized in that the liquid crystal lens comprises a first liquid crystal lens, a second liquid crystal lens, a third liquid crystal lens, and a fourth liquid crystal lens. The lighting device according to claim 12, characterized in that the first liquid crystal lens, the second liquid crystal lens, the third liquid crystal lens, and the fourth liquid crystal lens act on different polarized light of the incident light.

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