JP5297107B2 - Lighting device and display device - Google Patents

Description

  The present invention relates to an optical component, and more particularly to an optical component that can be suitably used for viewing angle control. The present invention also relates to an illumination device and a display device using such an optical component.

  Optical parts that use viewing angle control technology are used in displays such as liquid crystal displays to prevent peeping on mobile phone displays and personal computer displays and to prevent reflection on the front panel of car navigation systems. Such an optical component allows light from the display to be emitted only within a certain viewing angle range.

As such an optical component, there is a louver disclosed in Non-Patent Document 1. In this louver, a plurality of light shielding plates are arranged in one direction with their main surfaces facing each other. According to such a louver, it is possible to block light incident on the louver at an angle or more.
"View control technology in Shin-Etsu VCF", Monthly Display May 2006, pages 62-69

  However, the louver described in Non-Patent Document 1 also blocks a part of the light having an angle to be transmitted. As a result, it is necessary to increase the output of the light source in order to increase the brightness of the display having this louver.

  Accordingly, an object of the present invention is to provide an optical component having a viewing angle control function and high light utilization efficiency. Another object of the present invention is to provide an illumination device and a display device using such an optical component.

  The optical component of the present invention includes a first lens array, a second lens array, and a light shielding portion array. The first lens array includes a plurality of first lens elements arranged in one direction. The second lens array includes a plurality of second lens elements arranged in one direction. The light-shielding part array has a plurality of light-shielding parts arranged so as to be spaced apart from each other in one direction. The plurality of first lens elements have a convex incident surface. The plurality of second lens elements have a convex emission surface. The first lens array condenses a part of incident light between the plurality of light shielding portions and couples the incident light to the second lens array, and the incident direction of the part of the incident light is a plurality of first lens elements. Another part of the incident light having an incident angle larger than the angle formed with respect to the optical axis is at least partially coupled to any of the plurality of light shielding portions.

  According to the optical component of the present invention, part of incident light having a small angle formed by the incident direction with respect to the optical axis of the first lens element is incident between the light shielding portions by the first lens array. And is emitted from the second lens array. On the other hand, incident light having a large angle formed by the incident direction with respect to the optical axis of the first lens element is blocked by the light blocking portion. Further, since the emission surface of the second lens element is a convex surface, the light coupled to the second lens array is emitted at a small angle with respect to the optical axis of the second lens element. Therefore, in this optical component, the viewing angle provided by the emitted light is small, and the use efficiency of light with a small angle formed by the emission direction with respect to the optical axis of the second lens element is enhanced.

  In the optical component of the present invention, it is preferable that the light shielding portion is not positioned on the optical axis of the plurality of first lens elements and on the optical axis of the second lens element. In the optical component according to the aspect of the invention, it is preferable that the light shielding portion is positioned between the boundary between the adjacent first lens elements and the boundary between the adjacent second lens elements. In addition, it is preferable that the optical axes of the plurality of first lens elements coincide with the optical axes of the plurality of second lens elements. Cylindrical lenses can be used as the plurality of first lens elements and the plurality of second lens elements.

  The present invention also relates to an illumination device, and the illumination device includes a light source and a light guide plate that guides light emitted from the light source to the optical component. In addition, if a light guide plate is a member which has the function to guide light, it will contain arbitrary members, for example, will contain a diffuser plate.

The present invention also relates to a display device, and the display device includes the illumination device described above,
A liquid crystal panel that receives and emits light emitted from the illumination device.

  As described above, according to the present invention, an optical component having a viewing angle control function and high light utilization efficiency is provided. Moreover, according to this invention, the illuminating device and display apparatus using this optical component are provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a diagram schematically showing an optical component according to an embodiment. Hereinafter, the arrangement direction of the plurality of first lens elements in the first lens array of the optical component may be referred to as the x direction. A direction from the first lens array to the second lens array is referred to as a z direction, and a direction orthogonal to the x direction and the z direction is referred to as a y direction. FIG. 1A shows an optical component viewed in the y direction, and FIG. 1B shows an optical component viewed in the x direction.

  The optical component 10 shown in FIG. 1 includes a first lens array 12, a second lens array 14, and a light shielding portion array 16. The first lens array 12 and the second lens array 14 are, for example, cylindrical lens arrays, that is, so-called lenticular lenses. In the optical component 10, a light shielding unit array 16 is provided between the first lens array 12 and the second lens array 14.

  The first lens array 12 includes a plurality of first lens elements 12a. The plurality of first lens elements 12a are arranged in one direction, that is, in the x direction. Each of the first lens elements 12a includes a convex incident surface 12b. That is, the first lens element 12a has a convex surface on the side opposite to the boundary between the light-shielding portion array 16 and the first lens element 12a. In the present embodiment, each of the first lens elements 12a is a cylindrical lens.

  The second lens array 14 includes a plurality of second lens elements 14a. The plurality of second lens elements 14a are also arranged in one direction. In the present embodiment, the plurality of second lens elements 14a are also arranged in the x direction. That is, the second lens elements 14a are arranged in the same direction as the arrangement direction of the plurality of first lens elements 12a. Each of the second lens elements 14a includes a convex emission surface 14b. That is, the second lens element 14a has a convex surface on the side opposite to the boundary between the light-shielding portion array 16 and the second lens element 14a. In the present embodiment, each of the second lens elements 14a is also a cylindrical lens.

  The light-shielding part array 16 has a plurality of light-shielding parts 16a. In the present embodiment, each of the plurality of light shielding portions 16a has a plate shape. The plurality of light shielding portions 16a are arranged so as to be separated in one direction. In the present embodiment, the plurality of light shielding portions 16a are arranged in the same direction as the arrangement direction of the plurality of first lens elements 12a. The plurality of light shielding portions 16a extend along a plane that intersects the arrangement direction. In the light shielding part array 16 of the present embodiment, a member transparent to incident light, for example, resin is embedded in the space 16b between adjacent light shielding parts 16a.

  In the present embodiment, the period of the plurality of first lens elements 12a, the period of the plurality of second lens elements 14a, and the period of the plurality of light shielding portions 16a are all the same period. A light shielding portion 16a is provided between the boundary between the adjacent lens elements 12a and the boundary between the adjacent second lens elements 14a. Further, the position of the boundary between the adjacent first lens elements 12a in the arrangement direction of the first lens element 12a and the position of the boundary between the adjacent second lens elements 14a in the same direction coincide with each other. . That is, the optical axis of the first lens element 12a coincides with the optical axis of the second lens element 14a.

  Hereinafter, the locus of light incident on the optical component will be described in detail. FIG. 2 is a diagram illustrating a locus of light incident on the optical component according to the embodiment. In FIG. 2, the locus of the light L1 (light having an incident direction of 0 °) that enters the optical component 10 in parallel with the optical axis Z1 of the first lens element 12a is indicated by a solid line. Moreover, the locus | trajectory of the light L2 with a small angle which the incident direction makes with respect to the optical axis Z1 among the incident light to the optical component 10 is shown with the broken line. Further, among the incident light to the optical component 10, the locus of the light L3 having a large angle formed by the incident direction with respect to the optical axis of the first lens element 12a is indicated by a dotted line.

  As shown in FIG. 2, light L1 and L2 having a small angle formed by the incident direction with respect to the optical axis Z1 among the incident light to the optical component 10 are condensed in the space 16b by the first lens element 12a. And coupled to the second lens element 14a. The light that reaches the second lens element 14a is emitted so that the angle formed with respect to the optical axis Z2 of the second lens element 14a is small.

  On the other hand, of the incident light to the optical component 10, the light L3 having an angle formed with respect to the optical axis Z1 that is larger than the light L1 and the light L2 is coupled to the light shielding portion 16a. Therefore, the light L3 is shielded by the light shielding part 16a and is not coupled to the second lens element 14a.

  As described above, the optical component 10 is coupled to the second lens array 14 without shielding the incident light whose incident direction is small with respect to the optical axis Z1 of the first lens element 12a by the light shielding portion 16a. can do. Further, the light incident on the second lens array 14 is emitted so that the angle formed by the emission direction with respect to the optical axis Z2 is small. Therefore, the optical component 10 can reduce the unnecessary light loss due to the light shielding portion 16a and increase the light utilization efficiency while realizing a narrow viewing angle.

  FIG. 3 is a diagram illustrating a relationship between the light emission angle and the transmittance of the optical component according to the embodiment. In FIG. 3, the horizontal axis indicates the light emission angle, and the vertical axis indicates the ratio of the light power emitted at a certain emission angle and the incident power of the light to the optical component. In FIG. 3, the characteristic indicated by the solid line is the characteristic of the optical component having the lens array, that is, the optical component of this embodiment, and the characteristic indicated by the dotted line is the characteristic of the conventional optical component without the lens array.

The characteristics for the optical component of the present embodiment shown in FIG. 3 are obtained for optical components having the following parameters.
Thickness on the optical axis of the first lens element: 0.3 mm
First lens element and second lens element: cylindrical lens Curvature of incident surface of first lens element and exit surface of second lens element: 0.5 mm
Shapes of the exit surface of the first lens element and the entrance surface of the second lens element: Period of the flat first lens element and the second lens element: 0.6 mm
Distance between the first lens element and the second lens element: 1.2 mm
First lens element material: polycarbonate (refractive index: 1.59).
Second lens element material: polycarbonate (refractive index: 1.59)
Light-shielding part thickness: 50 μm
Shading length: 1mm
Period of light shielding part: 0.6 mm
Material of the light shielding part: Silicone rubber colored in black Material of the space between the light shielding parts: Silicone rubber (refractive index: 1.43)

  As is clear from FIG. 3, in the optical component in the present embodiment, the transmittance of the emitted light having a large angle formed by the emission direction with respect to the optical axis of the second lens element is small, and the emission direction is the second value. The transmittance of the emitted light with a small angle formed with respect to the optical axis of the lens element is large. Therefore, this optical component can improve the utilization efficiency of light having a smaller emission angle than conventional optical components.

  The preferred embodiments of the present invention have been described above. In the optical component of the present invention, it is preferable that the interval between the adjacent light shielding portions, the interval between the adjacent first lens elements, and the interval between the adjacent second lens elements are equal. Further, it is preferable that the first lens element and the second lens element have positive power in the zx plane.

  Moreover, it is preferable that the boundary position in the arrangement direction of the adjacent first lens elements coincides with the position in the same arrangement direction of the light shielding portions. The configuration in which the light shielding portion is positioned on the optical axis of the first lens element is not preferable because light having a small incident angle with respect to the optical axis of the first lens element is shielded. The boundary position in the arrangement direction of the matching first lens elements and the position in the same arrangement direction of the light shielding parts may be slightly shifted.

  Further, the shape of the first lens element and the shape of the second lens element may be the same or different from each other. The length of the light shielding part in the z direction may be equal to or shorter than the distance from the first lens array to the second lens array. However, the length of the light shielding portion in the z direction is from the first lens array to efficiently shield light incident at a large angle with respect to the optical axis of the first lens element. About 1/2 of the distance to the lens array of 2 is necessary.

  The light-shielding part preferably has a transmittance of 0% at the wavelength of incident light (for example, 400 to 700 nm), but the desired effect of the present optical component can be obtained even with a transmittance of about 10%.

  Further, the period of the plurality of light shielding portions may be N times (N is an integer of 1 or more) the period of the plurality of first lens elements and the period of the plurality of second lens elements. FIG. 4 is a diagram schematically showing an optical component according to another embodiment. In the optical component 10A shown in FIG. 4, in a part of the light-shielding part array 16, the period (interval) between two adjacent light-shielding parts 16a is equal to the period of the plurality of first lens elements 12a and the plurality of second lens elements. It is twice the period of 14a. In such an optical component 10A, the light L having a large angle formed by the incident direction with respect to the optical axis Z1 of the first lens element 12a passes through the space 16b having a double cycle, and the second lens element The light is emitted at a large angle with respect to the optical axis Z2, but the amount is negligible.

  In addition, the period of the plurality of light shielding units may be partially different from the period of the plurality of first lens elements and the period of the plurality of second lens elements. FIG. 5 is a diagram schematically showing an optical component according to another embodiment. In the optical component 10B shown in FIG. 5, one light-shielding part 16a is displaced toward one light-shielding part among two other light-shielding parts 16a adjacent to the light-shielding part 16a. In the optical component 10B, a part of the light L having a small angle formed by the incident direction with respect to the optical axis Z1 of the first lens element 12a is shielded by the light shielding portion 16a, but the amount is negligible. .

  Further, the arrangement direction of the plurality of second lens elements may be different from the arrangement direction of the plurality of first lens elements and the arrangement direction of the plurality of light shielding portions. FIG. 6 is a diagram schematically showing an optical component according to another embodiment. In the optical component 10C shown in FIG. 6, the arrangement direction of the plurality of second lens elements 14a is inclined with respect to the arrangement direction of the plurality of first lens elements 12a and the arrangement direction of the plurality of light shielding portions 16a. Even in the optical component 10C, the light L1 incident at a small angle with respect to the optical axis of the first lens element 12a can be coupled to the second lens array. On the other hand, the light L3 incident at a large angle with respect to the optical axis of the first lens element 12a can be blocked by the light blocking portion 16a.

  Further, the light shielding portion may be inclined with respect to the optical axis of the first lens element. FIG. 7 is a diagram schematically showing an optical component according to another embodiment. In the optical component 10D shown in FIG. 7, the light shielding portion 16a is inclined with respect to the optical axis Z1 of the first lens element 12a. This inclination angle is acceptable up to about 2 °. Also in the optical component 10D, most of the light L1 having a small angle formed by the incident direction with respect to the optical axis Z1 can be coupled to the second lens array 14. On the other hand, most of the light L3 having a large angle formed by the incident direction with respect to the optical axis Z1 can be shielded by the light shielding portion 16a.

  Further, the boundary position between the adjacent second lens elements and the boundary position between the adjacent first lens elements may not coincide with each other in the arrangement direction. FIG. 8 is a diagram schematically showing an optical component according to another embodiment. In the optical component 10E shown in FIG. 8, the boundary position of the adjacent first lens elements 12a in the arrangement direction x and the position of the light shielding portion 16a in the direction x coincide with each other. On the other hand, the boundary position in the arrangement direction x of the adjacent first lens elements 12a does not match the boundary position in the arrangement direction x of the adjacent second lens elements 14a. Even in such an optical component 10E, if the deviation between the two boundary positions is slight, most of the light L1 having a small angle formed by the incident direction with respect to the optical axis Z1 of the first lens element 12a is second. On the other hand, most of the light L3 having a large incident angle with respect to the optical axis Z1 of the first lens element 12a can be shielded by the light shielding portion 16a. On the other hand, if there is a boundary position between the adjacent second lens elements 14a on the optical axis of the first lens element 12a, the emission angle of the emitted light from the second lens array becomes large. Absent.

  Hereinafter, a display device using the above-described optical component will be described. FIG. 9 is a diagram schematically illustrating a display device according to an embodiment. The display device 20 illustrated in FIG. 9 includes a lighting device 22 and a liquid crystal panel 24. The illumination device 22 includes the optical component 10, the light guide plate 26, the light source 28, and the reflection plate 30. In addition, the illuminating device 22 does not need to have the reflecting plate 30. In the display device 20, light incident on the end face of the light guide plate 26 enters the optical component 10. Part of the light incident on the optical component 10 enters the back surface of the liquid crystal panel 24 and is emitted from the surface of the liquid crystal panel 24. Since the display device 20 includes the optical component 10, the viewing angle is small. In addition, since the display device 20 includes the optical component 10, the light use efficiency is excellent.

  FIG. 10 is a diagram schematically illustrating a display device according to another embodiment. A display device 20A illustrated in FIG. 10 includes a lighting device 22A and a liquid crystal panel 24. The lighting device 22 </ b> A includes the optical component 10, the light source 28, and the diffusion plate 32. In the display device 20 </ b> A, light from the light source is diffused by the diffusion plate 32 and enters the optical component 10. Part of the light incident on the optical component 10 enters the back surface of the liquid crystal panel 24 and is emitted from the surface of the liquid crystal panel 24. Similarly to the display device 20, the display device 20A includes the optical component 10, and thus has a small viewing angle. The display device 20A is also excellent in light utilization efficiency. The display devices 20 and 20A may use any one of the optical components 10A to 10E instead of the optical component 10.

It is a figure which shows schematically the optical component which concerns on one Embodiment. It is a figure which shows the locus | trajectory of the light which injects into the optical component which concerns on one Embodiment. It is a figure which shows the relationship between the light emission angle of the optical component which concerns on one Embodiment, and the transmittance | permeability. It is a figure which shows schematically the optical component which concerns on another embodiment. It is a figure which shows schematically the optical component which concerns on another embodiment. It is a figure which shows schematically the optical component which concerns on another embodiment. It is a figure which shows schematically the optical component which concerns on another embodiment. It is a figure which shows schematically the optical component which concerns on another embodiment. It is a figure which shows schematically the display apparatus which concerns on one Embodiment. It is a figure which shows schematically the display apparatus which concerns on another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical component, 12 ... 1st lens array, 12a ... 1st lens element, 12b ... Incident surface, 14 ... 2nd lens array, 14a ... 2nd lens element, 14b ... Output surface, 16 ... Light-shielding Part array, 16a ... light-shielding part, 16b ... space, 20, 20A ... display device, 24 ... liquid crystal panel, 26 ... light guide plate, 28 ... light source, 30 ... reflecting plate, 32 ... diffusing plate.

Claims (6)

A light source;
A light guide plate for guiding light emitted from the light source;
An optical component that narrows the viewing angle of light incident from the light source via the light guide plate;
With
The optical component is
A first lens array having a plurality of first lens elements arranged in one direction;
A second lens array having a plurality of second lens elements arranged in one direction;
A light-shielding part array having a plurality of light-shielding parts arranged apart from each other in one direction;
With
The plurality of first lens elements have a convex incident surface,
The plurality of second lens elements have a convex exit surface,
The light-shielding part array is provided between the first lens array and the second lens array, and the first lens array is in contact with the light-shielding part array on the side opposite to the incident surface, The second lens array is in contact with the light-shielding part array on the side opposite to the exit surface,
The plurality of light-shielding portions extend across the middle between the first lens array and the second lens array,
The first lens array condenses a part of incident light between the plurality of light shielding portions and couples the incident light to the second lens array, and an incident direction of the part of the incident light is the plurality of incident light. Any one of the plurality of light-shielding portions at least partly with another part of incident light whose incident direction is greater than the angle formed with respect to the optical axis of the first lens element. To join,
Lighting device.   2. The illumination device according to claim 1, wherein the light shielding unit is not positioned on an optical axis of the plurality of first lens elements and on an optical axis of the plurality of second lenses.   The lighting device according to claim 2, wherein the light shielding unit is located between a boundary between the adjacent first lens elements and a boundary between the adjacent second lens elements.   The illumination device according to any one of claims 1 to 3, wherein an optical axis of each of the plurality of first lens elements and an optical axis of the plurality of second lens elements coincide with each other.   The lighting device according to any one of claims 1 to 4, wherein the plurality of first lens elements and the plurality of second lens elements are cylindrical lenses. The lighting device according to any one of claims 1 to 5,
A liquid crystal panel that receives and emits light emitted from the illumination device; and
A display device.

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