Liquid crystal display combined with signal input tablet

• US 4,945,348 A
• Filed: 04/19/1988
• Issued: 07/31/1990
• Est. Priority Date: 04/22/1987
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sato, Manabu, Ibamoto, Masahiko, Shimada, Satoshi, Kano, Mitsunari, Kuzunuki, Soshiro, Ohyama, Shinji
• Primary Examiner(s): Moore, David K.
• Assistant Examiner(s): Fatahiyar, M.
• Application Number:
  US07/183,225
• Time in Patent Office: 833 Days
• Field of Search: 340/707, 340/712, 340/784, 340/805, 178/18, 178/19, 350/330, 350/339 D, 350/334, 358/247, 358/250
• US Class Current: 345/104
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment

Abstract

In a liquid crystal display combined with a signal input tablet of the type which includes a light source, a liquid crystal display disposed on the light source and a transparent tablet for detecting a planar write position by a hand-writing pen which tablet is disposed on the liquid crystal display, the present invention is characterized in that a two-dimensional lens array is disposed as one-to-one erect imaging optical system between the liquid crystal display and the transparent tablet so that the display image of the liquid crystal display is projected as the same size erect image on the surface of the transparent tablet having a light diffusion operation.

Claims

1. In a liquid crystal display combined with a signal imput tablet comprising a tablet for detecting a planar write position by a hand-writing input pen, a liquid crystal display disposed on said table and a transparent protective plate disposed on said liquid crystal display and having a light diffusion operation, the improvement comprising a two-dimensional lens array disposed as one-to-one erect imaging optical system between said liquid crystal display and said transparent protective plate so that the display image can be projected as the same size erect image on the surface of said transparent protective plate thereby elementating parallax otherwise existing between the liquid crystal display and the input panel.

2. A liquid crystal display combined with a signal input tablet according to claim 1, wherein two stages of two-dimensional microlens arrays are used as said one-to-one erect imaging optical system.

3. A liquid crystal display combined with a signal input tablet according to claim 1, wherein said two stages of microlens arrays are formed integrally on the front and reverse of said transparent protective plate.

4. A liquid crystal display combined with a signal input tablet according to claim 2, wherein one stage of said two stages of microlens arrays is formed integrally on the reverse of said transparent protective plate while the other is formed integrally on the front surface of said liquid crystal display.

5. A liquid crystal display combined with a signal input tablet according to claim 1, wherein three stages of two-dimensional microlens arrays are used as said one-to-one erect imaging optical system.

6. A liquid crystal display combined with a signal input tablet according to claim 5, wherein two stages of said three stages of two-dimensional microlens arrays are formed integrally on the front and reverse- of one transparent plate.

7. In a liquid crystal display combined with a signal imput tablet comprising a light source, a crystsl display disposed on said light source and a transparent tablet for detecting a planar write position by a hand-writing pen, disposed on said liquid crystal display, the improvement comprising a two-dimensional lens array dispoded as one-to-one erect imaging optical system between said liquid crystal display and said transparent tablet so that the display image of said liquid crystal display is projected as the same size erect image on the surface of said transparent tablet having a light diffusion operation thereby eliminating parallax otherwise existing between the liquid crystal and the input panel.

8. A liquid crystal display combined with a signal input tablet according to claim 7, wherein two stages of two-dimensional microlens arrays are used as said one-to-one erect imaging optical system.

9. A liquid crystal display combined with a signal input tablet according to claim 8, wherein said two stages of two-dimensional microlens arrays are formed integrally on the front and reverse of a transparent plate.

10. A liquid crystal display combined with a signal input tablet according to claim 8, wherein one stage of said two stages of two-dimensional microlens arrays is formed integrally on the reverse of said transparent tablet while the other is formed integrally on the front surface of said liquid crystal display.

11. A liquid crystal display combined with a signal input tablet according to claim 7, wherein three stages of two-dimensional microlens arrays are used as said one-to-one erect imaging optical system.

12. A liquid crystal display combined with a signal input tablet according to claim 11, wherein two stages of said three stages of two-dimensional microlens arrays are formed integrally on the front and reverse of one transparent plate.

13. A liquid crystal display combined with a signal input tablet according to claim 7, wherein a two-dimensional rod lens array is used as said one-to-one erect imaging optical system.

14. A liquid crystal display combined with a signal input tablet according to claim 11, wherein the focal length and diameter of each lens of the intermediate two-dimensional microlens array among said three stages of two-dimensional microlens arrays are smaller than those of the lenses of the other two-dimensional microlens arrays and the spacing between the individual lenses is buried by a shading mask.