JP4619248B2 - LIGHTING DEVICE AND DISPLAY DEVICE USING THE LIGHTING DEVICE - Google Patents

Description

  The present invention mainly relates to an illuminating device, and more particularly, the present invention relates to an illuminating device and a display device that vary an irradiation angle of an emitted light beam using an optical structure and an operating device.

  In many scenes such as the illumination field, the display field, and the optical communication field, there is a demand for brightness control and directivity control of emitted light. For example, it is necessary to control the viewing angle by controlling the brightness of the display of the liquid crystal display by adjusting the brightness of the backlight used in the liquid crystal display, or by controlling the light directivity of the backlight. There is a demand for making it possible to see the display of the liquid crystal display in a wide range, making it possible to see the display of the liquid crystal display only in a narrow range, and preventing peeping.

  In addition to the requirement to control the brightness characteristics and viewing angle of lighting / display devices, it is possible to use only low beams and high beams for automobile headlights, and to change only the display direction at a certain viewing angle. There is a demand for controlling the irradiation angle of the emitted light, such as a liquid crystal display that can be used, depending on the situation.

  Such a requirement is that one or more optical sheets for controlling the light beam having the function of aligning incident light in a predetermined direction are stacked on the irradiation angle of a light source such as a backlight and on the exit opening of the housing surrounding the light source. Thus, an optical sheet that can control the luminance characteristics and viewing angle of the light beam is used. By using this optical sheet, it is possible to contribute to thinning of the illumination / display device.

In recent years, normally used optical sheets have incorporated a brightness enhancement effect and a viewing angle enhancement effect, but do not have the function of controlling the irradiation angle of the emitted light beam according to the present invention. (Patent Document 1)
Japanese Patent Publication No. 7-7162

  In order to control the irradiation angle of the emitted light, there is a method of directly changing the irradiation angle of illumination, such as directly moving a light source. However, particularly for a display / illumination device that is desired to be thin and light, such as a liquid crystal display, it is desired that the illumination angle of the illumination / display device can be controlled by other means without directly moving a light source such as a backlight.

  Therefore, an illumination / display device that can control the irradiation angle by using the following optical sheet as an optical sheet for controlling the irradiation angle of the emitted light was manufactured.

  In an illumination / display device including a light source and an optical sheet to which an optical structure having a light beam direction control function is added to light from the light source, at least light from the light source passes through the optical sheet. A first optical sheet having an opening, a region where light from the light source is blocked, and a second lens effect that transmits light that has passed through the opening and aligns the light beam direction of the transmitted light. In the optical sheet that is arranged so that the first optical sheet always includes the focal point or the focal region formed by the second optical sheet, the opening of the first optical sheet is Similarly to the state in which the focal position is substantially coincident when parallel light is incident from a certain direction on the second optical sheet side, it is flat from a direction different from the direction on the second optical sheet side. And a state in which substantially coincides with the focal position when the light is incident, as able to produce each have a means for relatively horizontally moving the first optical sheet and the second optical sheet.

The focal point (20) is a point where an incident line parallel to the optical axis forms an image in the optical system, and if it is a microlens array (FIG. 5) in which a large number of hemispherical lenses are gathered, each hemispherical lens. , Each point where the incident line parallel to the optical axis forms an image becomes the focal point (20).
The focal point collection region (21) indicates, for example, a region where focal points are continuously gathered in a lenticular lens (FIG. 3) in which the lens continuously extends like a kamaboko shape.

  FIG. 1 shows a typical configuration example of a lighting device of the present invention. The inner surface of the housing (2) that covers the light source (1) is made of a high reflectance member. A first optical sheet (4) and a second optical sheet (5) are provided at the light exit (3) portion of the housing (2). The first optical sheet (4) has, on the light incident side, a portion (6) that does not transmit light and exhibits a reflection effect, and an opening (7) that transmits light is provided in a part thereof. The light emitted from the light source enters the second optical sheet (5) through this opening. The second optical sheet (5) has a portion (8) showing a lens effect, and is designed so that its focal point is in the vicinity of the back surface of the sheet. In addition, the second optical sheet (5) and the first optical sheet (4) are collimated from one direction in which the opening of the first optical sheet is on the second optical sheet side by the actuator (9). It is possible to move between two points with respect to the focal position when parallel light is incident from a direction different from the above-mentioned direction on the second optical sheet side in the same manner as the focal position when the light is incident. The moving direction needs to be substantially horizontal with respect to the sheet surface.

  The focal position of the lens structure part (8) of the second optical sheet (5) when the opening (7) of the first optical sheet (4) is irradiated with parallel light from a direction perpendicular to the optical sheet surface, for example. 2A, most of the light incident from the opening (7) of the second optical sheet (5) is incident on the lens structure (8) immediately above the second optical sheet (5), and enters the sheet. The optical axis is aligned in a direction perpendicular to the optical axis. The light applied to the portion other than the opening (7) is reflected by the reflecting member of the housing (2) having a high reflectance or the reflecting portion of the optical sheet, and after being reflected several times, the opening (6). To reach. As a result, an illuminating device that emits light having strong directivity is obtained.

  The lens structure (2) of the second optical sheet (5) when the opening (7) of the first optical sheet (4) is irradiated with parallel light from a direction inclined at an angle θ from the vertical direction with respect to the optical sheet surface ( 8) When moving from the focal position in the vicinity of the focal position in the vertical direction to a position separated by a distance S in the horizontal direction from the focal position when irradiated from the vertical direction, as shown in FIG. The direction can be changed to the angle θ direction.

  Strictly speaking, the focal position of the lens structure (8) of the second optical sheet (5) when the opening (4) of the first optical sheet is irradiated with parallel light from a direction perpendicular to the optical sheet surface. When the parallel light is irradiated from the angle θ direction, the focal position does not exist in the same plane (horizontal plane with the optical sheet) as the focal position in the vertical irradiation, and the second optical sheet It exists in the position which shifted | deviated slightly to the lens structure part (8) side. Therefore, when it is desired to precisely adjust the focal position, not only horizontal movement but also vertical movement is required. However, movement in the horizontal, vertical, and both directions complicates the actuating device (9), which makes the device large and costly. In practice, if the deviation is about 10% or less of the focal length, there is no significant influence, and it is desirable to substitute only the movement in the horizontal direction.

In addition, when it is desired to keep the central luminance from changing even if the illumination angle characteristic is changed, such as for display applications, it is necessary to provide a mechanism for adjusting the power supplied to the lighting device to keep it constant.
The actuating device may be any device that can control the positional relationship between the two optical sheets, and a piezoelectric element, an electromagnet, a motor, a spring, or the like is used.

  In this configuration example, only two optical sheets of the present invention are used at the light exit portion. For example, a commercially available diffusion plate is provided on the light incident side of the optical sheet, and a scattering sheet is provided on the light exit side. Thus, there is no problem even if a plurality of other optical sheets are used. Further, the surface in the text means an optical surface, and there is no problem even if a transparent protective film or the like is provided on the surface of the reflecting member.

According to the present invention, the second optical sheet side is the same as the state where the opening of the first optical sheet substantially coincides with the focal position when parallel light is incident from one direction on the second optical sheet side. The first optical sheet and the second optical sheet are moved relative to each other horizontally so that a state substantially coincident with the focal position when parallel light is incident from a direction different from the above direction can be created. As a result, the irradiation angle peak changes. By utilizing this change, it is possible to provide an illumination device and a display device that can control the irradiation angle characteristics.

  Hereinafter, although the illuminating device and display apparatus concerning this invention are demonstrated based on figures, this invention is not limited to these embodiment at all.

Example 1
First, a lenticular lens sheet having a structure shown in FIG. 3A was produced as a second optical sheet (5) by hot embossing. As the molding material, acrylic having a refractive index of 1.5 was used, the radius of curvature of the lenticular lens was 0.8 mm, the lens pitch was 1 mm, and the thickness from the lens apex position to the back of the sheet was 2.28 mm.

  In order to prevent light from passing through one side of a polyethylene terephthalate film having a thickness of 100 μm as the first optical sheet (4) separately from the sheet, silver was formed by sputtering and an opening was provided by a photolithography method. The shape of the opening was a slit and the opening width was 0.4 mm.

  The two optical sheets were placed above the light source as shown in FIG. The opening of the first optical sheet (4) can be varied using the actuator (9) at a focal position and a position shifted 0.3 mm horizontally from the focal position.

  As shown in FIG. 4A, the actuating device has a configuration in which an electromagnet (14) and a permanent magnet (11) are combined. A magnetic force is applied to the iron cores (12) and (13) by the electromagnet (14) to move the first optical sheet (4) horizontally from the focal position of the lens sheet as the second optical sheet (5). Once attached to one side, the position is held by the permanent magnet, so the power of the electromagnet may be turned off. The luminance characteristics of this lighting device were measured by changing the distance S. The measurement results are shown in FIG.

(Example 2)
As the second optical sheet (5), a lenticular lens sheet having a structure shown in FIG. 3B was produced by a hot embossing method. The molding material is acrylic with a refractive index of 1.5, the radius of curvature of the lenticular lens is 80 μm, the lens pitch is 200 μm, the flat part width between the lenses is 49.6 μm, and the thickness from the lens apex position to the back of the sheet is 210 μm. .

  Separately from the sheet, silver was formed by sputtering on one side of a 50 μm-thick polyethylene terephthalate film as the first optical sheet (4), and an opening was provided by photolithography. The shape of the opening was a slit, and the opening width was 40 μm.

  These two optical sheets were installed in the opening of the housing as shown in FIG. Also on the inner surface of the housing, silver was formed by sputtering, and titanium oxide particles were dispersed and applied to the binder so as to diffusely reflect on the sputtered silver layer. The reflectance measured with an integrating sphere was 96%. The opening can be varied by using the actuator (9) at a focal position and a position shifted by 76 μm in the horizontal direction.

  The actuating device moved the first optical sheet (4) left and right using a piezoelectric (piezo) element (16) as shown in FIG. 4 (b). The luminance characteristics of this lighting device were measured by changing the distance S. The measurement results are shown in FIG.

(Example 3)
First, as a second optical sheet (5), a microlens array sheet having a structure shown in FIG. As the molding material, acrylic having a refractive index of 1.5 was used, the radius of curvature of the microlens was 20 μm, and the thickness from the lens apex position to the sheet back surface was 55 μm. The arrangement of the lenses was a hexagonal close-packed arrangement, and the shortest distance between the lens apexes (lens pitch) was 35 μm.

  Separately from the sheet, silver was formed by sputtering on one side of the sheet as the first optical sheet (4), and the opening shown in FIG. 6 was provided by photolithography. The shape of the opening was circular, and the opening diameter was 10 μm.

  These two optical sheets were installed in the opening of the housing as shown in FIG. Also on the inner surface of the housing, silver was formed by sputtering, and titanium oxide particles were dispersed and applied to the binder so as to diffusely reflect on the sputtered silver layer. The reflectance measured with an integrating sphere was 96%. The opening can be varied by using the actuator (9) at a focal position and a position shifted by 18 μm in the horizontal direction.

  The actuating device was configured to be manually actuated as shown in FIG. When the button (18) is pushed and turned, it leaves the focal position, and when the button (18) is turned, it returns to the focal position by the leaf spring (17). The luminance characteristics of this lighting device were measured by changing the distance S. The measurement results are shown in FIG.

Example 4
First, a lenticular lens sheet having a structure shown in FIG. 3B was prepared as a second optical sheet (5) by hot embossing. The molding material is acrylic with a refractive index of 1.5, the radius of curvature of the lenticular lens is 80 μm, the lens pitch is 200 μm, the flat part width between the lenses is 49.6 μm, and the thickness from the lens apex position to the back of the sheet is 210 μm. .

  Separately from the sheet, silver was formed by sputtering on one side of a 50 μm-thick polyethylene terephthalate film as the first optical sheet (4), and an opening was provided by photolithography. The shape of the opening was a slit, and the opening width was 40 μm.

  These two optical sheets were installed in the opening of the housing as shown in FIG. Also on the inner surface of the housing, silver was formed by sputtering, and titanium oxide particles were dispersed and applied to the binder so as to diffusely reflect on the sputtered silver layer. The reflectance measured with an integrating sphere was 96%. The opening can be varied by using the actuator (9) at a focal position and a position shifted by 76 μm in the horizontal direction.

  The drawing unit (19) in FIG. 12 may be any unit that is generally used as a display device that displays an image or video by irradiating light from a light source. Examples thereof include a liquid crystal panel. Here, a liquid crystal panel was installed on the optical sheet as a drawing unit (19).

The actuating device moved the first optical sheet (4) left and right using a piezoelectric (piezo) element (16) as shown in FIG. 4 (b). The luminance characteristics of this display device were measured by changing the distance S. The measurement results are shown in FIG.

(Explanation of measurement results)
10 to 13 show the viewing angle dependence of the luminance of the manufactured lighting device. Data in which the light source power is fixed to the same value at a position shifted from the focal position is shown. When there is an opening at the focal position when irradiating horizontal light from the vertical direction, there is a luminance peak in the irradiation direction perpendicular to the optical sheet surface (0 °), and the horizontal opening from the vertical irradiation focal position. It can be seen that when the part is separated, the irradiation direction also tilts from the vertical direction.

  Therefore, it was found that the irradiation direction can be controlled in the illumination device by following the modes of Examples 1 to 3 and the display device by following the mode of Example 4, respectively.

It is a schematic block diagram which shows an example of a structural example of the illuminating device of this invention. It is explanatory drawing which shows the effect of this invention. It is sectional drawing which shows an example of the lenticular lens sheet used for this invention. It is a schematic block diagram which shows an example of the operating device of the illuminating device used for this invention. It is the perspective view and sectional drawing which show an example of the micro lens array sheet used for this invention. It is sectional drawing which shows an example of the optical sheet used for this invention. It is a schematic block diagram which shows an example of a structural example of the illuminating device of this invention. It is a schematic block diagram which shows an example of a structural example of the illuminating device of this invention. It is a schematic diagram showing an example of a configuration example of a display device of the present invention. It is a characteristic view which shows an example of the luminance characteristic of the illuminating device of this invention. It is a characteristic view which shows an example of the luminance characteristic of the illuminating device of this invention. It is a characteristic view which shows an example of the luminance characteristic of the illuminating device of this invention. It is a characteristic view which shows an example of the luminance characteristic of the illuminating device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Housing 3 Light emission port 4 1st optical sheet 5 2nd optical sheet 6 Structure part which shows reflection effect 7 Opening part which permeate | transmits light 8 Part which shows lens effect 9 Actuator 10 Light source light 11 Permanent magnet 12 Iron core 13 Iron core 14 Electromagnet 16 Piezoelectric element 17 Slide switch 18 Button 19 Liquid crystal panel 20 Focus 21 Focus collection area

Claims (7)

In an illuminating device including a light source and an optical sheet to which an optical structure having a light beam direction control function is added to light from the light source, the optical sheet has an opening through which at least light from the light source passes. And a first optical sheet having a region where light from the light source is blocked, and a second optical having a lens effect that allows light that has passed through the opening to pass therethrough and aligns the light beam directions of the transmitted light. In the optical sheet that is composed of a sheet and is arranged so that the first optical sheet always includes a focal point or a focal region formed by the second optical sheet, the opening of the first optical sheet is the second. In the same manner as the focal position when parallel light is incident from one direction on the optical sheet side, the parallel light is emitted from a direction different from the direction on the second optical sheet side. And a state in which substantially coincides with the focal position when allowed Isa, as able to produce, respectively, the illumination device characterized in that it comprises a means for relatively horizontally moving the first optical sheet and the second optical sheet In a display device having a light source and an optical sheet to which an optical structure having a control function of a light beam direction is added to light from the light source, the optical sheet has an opening through which at least light from the light source passes. And a first optical sheet having a region where light from the light source is blocked, and a second optical having a lens effect that allows light that has passed through the opening to pass therethrough and aligns the light beam directions of the transmitted light. In the optical sheet that is composed of a sheet and is arranged so that the first optical sheet always includes a focal point or a focal region formed by the second optical sheet, the opening of the first optical sheet is the second. In the same manner as the focal position when parallel light is incident from one direction on the optical sheet side, the parallel light is emitted from a direction different from the direction on the second optical sheet side. And a state in which substantially coincides with the focal position when allowed Isa, as able to produce, respectively, a display device characterized in that it comprises a means for relatively horizontally moving the first optical sheet and the second optical sheet
3. An illumination device and a display device according to claim 1, wherein in the second optical sheet according to claim 1, a region having a flat surface with a small lens effect is present between the structural portions exhibiting the lens effect. 4. The display device and the illumination device according to claim 1, wherein the display device and the illumination device include a housing that covers the periphery of the light source, and a surface on the light source side reflects light from the light source. Display / lighting device 5. An illuminating device and a display device, wherein a piezoelectric element is used as the moving means of the first and second optical sheets according to claim 1. An illuminating device and a display device, wherein an electromagnet is used as the moving means of the first and second optical sheets according to claim 1. 5. A lighting device and a display device, wherein a spring is used as the moving means of the first and second optical sheets according to claim 1.

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